Organization in the human body

 Our bodies are very organised, because without it, we would die.

There is a hierarchy of organisation for our bodies, and they are: the Cells, Tissues, Organs, and Organ systems. 

Cells are the smallest unit of life on this planet, being small and specialised to take on tasks.
Tissues are large groups of specialised cells and often coat large amounts of space on our bodies, like the tissues in our mouths, and the tissues that form when we hurt we hurt ourselves, named scar tissues.
Organs and Organ Systems, are for well what they are named. These are often known as Lungs, Kidneys, your Heart, and other organs. Organ systems are sytems by organs in order for you to breath, like the respitory system.

Acceleration

Acceleration is the speed gained over time; for example, a sports car is much faster than a normal car because of its acceleration.

The calculation is the change in Velocity divided by Time. The standard way of writing it is m/s, or meters per second.
If we simplify it, is it m/s^2 or meters per second squared, something to keep in mind is that both velocity and acceleration are different, as if we take a car and drive it on a road, and take photos every second and overlay them together, it looks like the car is getting further and further away each photo. 

This is an accurate depiction of what acceleration looks like. This style of diagram is named 'the oil-drop diagram' because it looks like an oil drop.

Another thing to keep in mind is that velocity is a vector, meaning that there is a direction the object is moving in.
But if the object is slowing down instead of speeding up, then it is decelerating, 

Plants and Animal cells

 Plants and animals are different, but the cells are very similar, with some subtle differences.

Plant and animal cells have a cell membrane, which is the protective wall around the cell, along with the Cytosol, which holds all of the small organelles. Such as the Nucleus and Mitochondria, which are in the fluid part of the cytoplasm.

There is also a big difference.
The plant cell has a 'cell wall' which is much bigger than the cell membrane and is what makes the plant rigid instead of floppy.

They also have these small green things, named Chloroplasts, which also come with the benefit that, making these plants green, they will convert sunlight into their own food and sugars for the mitochondria to break down for the plant. Mitochondria provide energy for the cell to move things in and out of the cell membrane, as it isn't a static wall and lets things go in and out while expending energy.

Hinduism, the ideas of Brahman, Atman, Samsara and Moksha.

Hinduism is one of the oldest religions in the world, dating back as far as 5,000 years ago or 1500 BCE.

There are some elements that come from the Vedic period and shape the core beliefs of modern Hinduism. It is believed that the roots of Hinduism come from an Indo-Aryan people native to central Asia.

Hinduism is a merged religion since there are many ways to practice Hinduism, such as the Sindhu in Sanskrit, and Hindus in Persian, and the Indus in Latin, this re

Position, Velocity, and Speed

 Position is a location, using references as a scale on where it is, if we were to put a toy car on a road, we don't really know where it is, but if we put say, a pole on it's left, then we can use the pole as 0, and any number afteer is is positive and any number before it is negitive. 

Location is a "vector", which is a direction of travel. 
If the car were to move, say 225 meters in 3 seconds, and it started at 10 meters, what would be the formula for it? First, we need to know the distance, which is a simple minus 25-10, which gives us 15.
Second, we need to have another value, which is something called velocity, meaning how fast something is going. We know that it travelled 15m in 3 seconds,  so we take the 15 and divide it by 3, which gives us '5'. So it we can confidently say that the car travelled 5m/s or 5 meters per second.

Now we can discuss speed, which is how fast an object is moving. Speed is the distance divided by time, which in this question is 15/3, which gives us 5m/s. 
Keep in mind that these equations are applicable when the object is moving at a constant rate. However, if the object is slowing down or speeding up, they depict the average speed of the object. 

One thing to keep in mind is that speed is just a value; it doesn't matter what direction the object is travelling, it only matters how fast. While distance is for calulating 'distance' and is for when it is travelling back and forth with positive and negative positions. 

Niger

 This country is Niger, not Nigeria, these are two different diferent African countries, and the males put on a beauty pagent for female judges that can choose the winner and the female judge will sleep with them.

Niger is bordered by 7 other countries, Algeria, Mali, Chad, Libya, Nigeria, Benin, Burkina Faso, and is landlocked and takes around 1.3millionn square kilometerrs or over 500,000 square miles, split into 7 regions with the captial Niamey in the south west, and the second largest city being Zinder in the southeast and Maradi in the central.

95% of the population lives in the south, where all the roads are, with only one road going into the mining town, Arlit. 
In the northeastern part is the Saharan Region, which only uses dirt roads, and there is a military outpost which patrols the border with Libya. 

The road from Libya into Niger passes by the Kouru Arkenne airstrip, with two airports the Diori Hamani International Airpot, and Agazes' Nano Dayak, they are working with Benin, to make a rail line.

During Colonial times Niger's borders were kind of weird because for a time, because unnti 1921, half off Chad's land because of the borders being drawn by the French and other Colonisers.

Their landmarks are very small and hard to find since the majority is in the Sahara desert, like the UTA flight 772 crash site monument in the sand, hundreds of kilometres from any buildings. And the Tenere tree, which is the only tree in around 400 kilometres, until a drunk driver strangely knocked it down in the 70s.

Other historical or interesting landmarks are: 
The Nguigmi desert caravan town, the Maradi palace and grand bazar, the National museum of Niger, the Djado and Djaba ruins, the Agadez grand Mosque, the Ayorou hippo tours, the Gobero cemetery site which is over than 10,000 years, the cave drawings of Tituidit and Dobous, the Tuareg festival, the Timia oasis town, Kaoure Giraffe reserve, the animal store of balleyara, the city of Zinder which is the cultural captial of Niger, the Berni corner and Sultan's palace.

Cell parts and their functions

There are many things built out of cells, and each cell is made of smaller functions that are necessary for it to carry out its functions.

First is the cell membrane, which is the cell's outer wall and is what separates the insides of the cell from the outside environment. Inside the cell is the cell's Cytoplasm, a jelly-like substance that holds all its contents very rigidly.

Inside the Cytoplasm are something called Organelles, which are small, organ-like structures that can carry out their functions. If you look at cells, there are small bean-like organelles, which are mitochondria, which are the "powerhouse of the cell". These organelles break down sugar molecules to help power the cell.

The Nucleus is what holds all the genes of the cell, and sort of like computer code to the cell on what to do to survive or to reproduce.

Cells and organisms

Cells are the building blocks of life. All organisms are built out of cells. Many cells can do things such as remove waste, use and produce energy, such as red blood cells that are in our bodies, or cells that cover mushrooms.

Our eyes are not strong enough to see the small cells in living things; instead, we use Microscopes to see things with a closer lens. Organisms that are built out of many cells are multicellular, while single-celled organisms are unicellular. 

An example of a unicellular organism is the E. coli bacteria. By itself, it is made to reproduce, make and use energy, and take in nutrients, and multicellular organisms use many cells to carry out their procedures.

All cells come from other cells, meaning that they are created or reproduced by cells.

States of Matter

 There are 3 states of matter: Solid, Liquid, and Gas. There is a theory named 'kinetic' or 'Particle theory' that explains these materials or particles are depicted as inelastic small balls.

For solids, the particles in a solid have a lot of attraction so that they don't get pulled apart easily. These particles can vibrate, but because of their strong attraction to each other, the particles are in a fixed position and don't move. 
But if we heat the solid up, it causes the particles inside the solid to vibrate quickly, causing them to reach their melting point, and then they break free of their bonds to turn into a liquid, which has very weak bonds between its particles and has the property of being able to change its shape to fit its container.
If we keep heating the liquid up, the particles' bonds will keep decreasing until there is no strength in the bonds and causing the liquid to turn into a gas.

These gases are strange because, since the bonds are very weak, the gas can occupy any container you put it in.
But if we heat up the gas in its container, it can either do one of two things. For example, if we use a balloon, it will expand the container, but if we use something rigid or fixed, like a metal can, it will cause the heat to build up into pressure.

If we cool the liquid, the weak forms of attraction will cause the bonds to be fixed in place, and if we cool it enough, it can cause the liquid to freeze.

If we are in a closed system, the change in states of matter will affect its density since the different states have different densities, but the mass stays constant as it is the same number of particles 

Sanskrit in English

Many languages' roots come from Sanskrit, as it serves as a baseline, and languages like Hindi, Bengali, and Punjabi, as well as other Indo-European languages like Italian and French, and Germanic languages such as English and German.

Sanskrit is the oldest source of a "Proto-Indo European language", in history.
Words like "Matr" (Sanskrit for mother) and "Pithr" (Sanskrit for father) are used in the English language as ways to address one's parents.

"Na" being "No", and "Dwar" meaning "door". 

Often, when a word goes from Sanskrit to a Latin or Germanic language, it turns the 'p' sounds into 'th' sounds, and the word 'matr' turns to 'mother'.

In the Vedas, there is a sky god named Dyauspitr, whose the word 'dayus' means sky, while the Greeks have Zeus Pater, which is eerily similar to each other in pronouciation, and the Roman god Jupiter (which is the Roman version of Zeus, is 'Jeu-piter', all of these words sound very similar when spoken, and the Vedas has Indra, which is dubed as the 'king of the gods' being the son of Dyauspitr.
Indra has many qualities that are not associated with Jupiter and Zeus. Indra is the god of the sky and is supposed to throw bolts of lightning, which is similar to the Norse god of lightning, Thor. Indra also has a hammer that can also throw lightning, similar to Thor.

Fuses & Earthing

 When we use electricity, there are dangers to using it as it can cause fires, causing a power surge, and sudden changes in current, which are all dangers when handling electrical appliances. 

Ways to mitigate these dangers are with circuit breakers, fuses, double insulation, and grounded or earth wires.
Circuit breakers and fuses work in similar ways, but they have differences as they both cut power to the rest of the circuit when too much current flows through it. 

How a fuse works is that a live wire is connected by a thin metal wire that, when too much current flows through the live wire and, the fuse melt,s cutting power from the circuit and potentially saving the appliance from breaking or getting overloaded, and these fuses come in different ratings for different applications.

If we take an appliance that needs a 3a or 3 amp current, to add a fuse to it we can add a fuse that is 5a or 5 amps so that it will shut off the current to it if the appliance gets affected by a power surge.
Or if an appliance runs at 10a, then using a 13 or 12 amp fuse is necessary.

The reason why we use fuses is that its cheep and simple to use, thats why when we have appliances such as toasters and microwaves often have built in fuses in their plugs, one downside is that fuses are a one time use, meaning that once the fuse stops a power surge, it is permenently distroyed has has to be replaced. 

The other way to stop a current from flowing during a surge is via a Circuit breaker. Instead of being perminently damaged when a power surge happens, it instead "trips" which disconects it from the circuit so that no fuse is spent and can be used, thats why in breaker boxes when the power in your house trips, you can just flip a switch and have your electricity restored to your house.

One of the dangers of a power surge is that the live wire (brown) touches the appliance directly or the appliance's casing, which causes the appliance to be charge with electricity, one way to stop the acsedental shocks from the live wire touching the appliance is via a "earth wire' which is a wire that provides another path for the current that was previously flowing though the appliance to instead be 'grounded' and even if the live wire would be touching the appliance directly, the ground wire should protect you from getting shocked.

Another way is to double insulate an appliance, which basically means to add a non-conductive outer layer, which is most commonly plastic. If a device like a smartphone, tablet or appliance has double insulation, most of the time it doesn't need an earth wire, two layers to protect the user from being shocked

Molecular & Empirical Formulas

A Molecular formula is a type of formula that displays the formula of a molecule with numbers and letters. This formula's depiction of the molecules is more precise, but it takes longer to write. An example of this formula is Glucose, which is C6H12O6, meaning there are 6 Carbon atoms, 12 Hydrogen atoms, and 6 Oxygen atoms.

The empirical formula it is much simplier to write but lacks in complexity and detail that writing it in the molecular formula would allow.
For example, CH2O means that for every Carbon and Oxygen, there are 2 Hydrogen atoms.

If you want to turn an molecular formula to an empirical formula, the first thing we need to know is the ratios of the atoms, so let's take a molecular formula of Ethane, which is C2H6. 

To make this simplier and into a empirical formula we must first make the numbers smaller, so we can devide the C2H6. And Divide it by 2 to get CH3, so it is an easier forumla.

Lets now convert CH3, which is a empirical formula into a chemical one.
We are given the MR or the Molar mass which is equal to 30, so in this MR = 30, and the empirical formula and  

The Vedic Period

As we know, the Indus Valley Civilisation, which is now in modern-day Pakistan and northwest India, then in the third millennium BCE and then in the second millennium BCE starts its decline. We still don't know why it declined. Maybe due to a natural disaster, maybe a river that was vital to them or maybe climate change. We still don't know. 

The Vedic period was the era of the Indo-Aryans in South Asia, who migrated into the Indus Valley during its decline.
We get the name Vedic from the literary works called the Vedas, which is a Sanskrit word meaning knowledge. These Vedic people are the baseline of modern Indian culture. 

The important Vedas are the Rigveda, Yajurveda, Samaveda, and Atharvaveda, with Rigveda being the oldest of the group. Rigveda first appeared at the start of the Vedic period, around 1500 BCE, and it continued until around 1200 BCE, which is around 3,000 - 3,500 years ago.

They were cattle herders, and they may have been nomadic and were expanding beyond the Indus River Valley, to the whole of what is now the Gangetic plain in north-east India and Bangladesh. 
They did become farmers around what is the late Vedic period and started becoming more like a kingdom.

Then, the Hindu stories or Epics of Mahabharata and Ramayana, these stories or poems were originally told verbally, but maybe during this late period or after the Vedic period, these stories would eventually be written down.

Sanskrit is one of the oldest Indo-European languages on earth, and it is related to languages like Greek and Latin, and some Germanic languages like Danish, Norwegian and Swedish. Sanskrit is as old as Mycenaean Greek and the Hittite Language.

The first documented piece of the Indus Valley Civilisation is from the Vedas, and they had a word which is Sindhu, which may  have been mispronounced and misspelt to the point that it may have turned into the word Hindu, then the word Indus may have turned into the word India.

There were also social structures and classes, named the Varnas, such as the Brahmins which are the teachers, scolars and the priests, the Kshatriyas which are the kings and the warriors, Vaishyas which are the farmers, merchants and the artisans and finally the Shudas which are the labourers.

 

Nutrients

 Nutrients are very important; without proper nutrients, we would not function properly.

The common nutrients are:
Carbohydrates, Lipids and Proteins.
Vitamins and Mineral ions.
Fibres and Water.

Nutrients are gathered from the foods that we eat, let's start off with the most common ones carbohydrates, lipids and proteins, these come from our pasta, potatoes and breads, these carbohydrates are often very starchy, these carbohydrates give us energy which is used for us to move around and conduct chemical reactions in our bodies.

Next are Lipids, which are the other name for 'fats', found in fatty foods and oils. These fats are commonly found in seeds, dairy products, and types of oily fish. The difference between these liquids and oils is that oils are liquid at room temperature, but fats are solid. 

They also provide energy to our bodies, but compared to carbohydrates, this energy source is more long-term since fat can be stored for longer compared to carbohydrates. Fats are also inside our bodies, with it being a layer of fat to keep us warm under our skin, and they also keep our organs safe.

Proteins are commonly found in seeds, fish and meats, and legumes like beans and lentils. These proteins are needed for growth and repairing damaged tissues, but the amount of energy that they can provide is much less compared to lipids or carbohydrates. If we don't have enough of either, the proteins can suffice.

Vitamins and Minerals are different as vitamins are from living organisms like while minerals are from inorganic sources, like iron, which is needed much less compared to vitamins.
Vitamin A are gathered from eating leafy vegetables and livers, other vitamins like vitamin C from oranges or other citrus fruits are meant to stop you from getting scurvy, which happens when you don't have enough vitamin C and can cause your gums to bleed. 
Vitamin D is gathered from standing in the sun, as, strangely enough, the body makes vitamin D from sunlight, which is the best way to get it.
Other sources, via eggs and oily fish, the purpose of vitamin D is that it helps your body absorb Calcium.

This is a good segue to what Calcium is, which is a mineral, and is commonly found in milk and leafy veggies. If you don't have enough Calcium, then your bones will deform from a disease named Rickets.
Last is iron. If you have done the experiment where you crush up cereal, you will find small magnetic chunks of iron in the cereal, which our bodies need for helping red blood cells transport oxygen throughout the body.
If you don't have enough iron, then you might get Anemia, which is when the body can't transport enough oxygen to your tissues, and is a vital part of haemoglobin. This is found in foods like red meats, beans and spinach.

Lastly is Fibre and Water are also nutrients with their own purposes. Fibre is considered to be a type of carbohydrate, but the key difference is that we don't absorb it into the body, its purpose is to help food move through our intestines, which helps us not get Diarrhea or be constipated.
Water is important since 70% of our bodies are made of water, and is found in all drinks. certain fruits also supply us with water, like strawberries and watermelons. We need it for chemical reactions in our bodies, along with making urine, which is waste and sweat, to keep our bodies cool. 

In order to keep a balanced diet, we need all of the nutrients. If we take too little, then we might contract certain diseases, or if we eat too much, then we might have too much excess fat, so that we would become obese.

Instead of using Joules for energy, we instead write the energy that food gives us with calories, so the more calories the more energy, as stated above the amount you need varies to what your doing, if your doing sports then you might need more food or energy to gain back the lost energy when doing activities, or if your growing as children need lots of energy to grow, while the elderly take less since they don't have to grow, and if your pregnant than you need to eat more since your body is forming an infant. 

Plugs and wires

One important thing about electricity is the plugs and wires, and when you need to repair them, you might notice that the different coloured wires are inside a plug.

The power that comes from the national grid is the main power supply; the current of the mains is an alternating current with around 240 volts flowing into households.
Keep in mind that the voltage may differ between which goes into our sockets in our homes.

Three wires are in a plug: the live one, the grounded or earth wire and the neutral one, all with an insulating plastic covering the copper wires.

Now, the way we differentiate the wires so that we don't shock ourselves is through the colours. brown is live, meaning all the voltage flowing through the plug is going through the brown one and has a potential difference of 230 volts. The blue one is the neutral one that will complete the circuit.
And lastly is the earth or ground wire, which is a stripped green wire that stops the plug housing from becoming live and shocking us when we grab the plug.
It does this by giving the electricity an alternative output so that the power flows out instead of into the plug housing.

The reason why the electricity from the live wire (brown) flows through the neutral wire (blue) is that they have a 0 potential difference compared to the live wire, which has, in this case, 240 volts.
Now, since humans also have 0 potential difference, we can act as a neutral wire and get shocked by electricity, too. This is why sticking forks into plug sockets even when they are "off" can still shock you, and in general, sticking things into sockets is bad.

AC & DC Current

An Alternating current which is commonly referered as AC, which is a type of current that will alternate between a positive and negitive charge, and this charge will fluctuate between voltages.
If your house is being supplied with 240 volts then the AC current will fluctuate between 240v to -240v, and it will aternate between the voltages on a set timer.

While a direct current or DC current is either a positive or negitive charge, since the positive charge is consistant, the most common use is in which makes it good for cells and batteries.

We can get graphs of the potental difference from the current is via a Oscilloscope, which measures the potental difference a current is producing by displaying it on a monitor, these monitors display the current in a wave.

How Temperature and PH levels affects the rate of reactions

Enzymes rely on temperature as the heat helps speed the reactivity, but for Enxymes to work efficiently they need to be at a stable temperature,
otherwise, if you keep increasing the heat it may break apart the bonds that hold the Enzyme together thus making the Enzyme change its active site which is where the Enzymes do their reactants if the shape change is too drastic then the Enzyme might not even help Catalyze by the Enzyme being unable to bind to the Substate.

The name of an Enzyme that has been hit with too much heat is called a Denatured Enzyme, if this does happen it is permanent and cannot be undone, Enzymes also have an optimal temperature and will work with high efficiency at a certain temperature, this is why our bodies always are 37.5 celsius.

Another deciding factor for Enzymes to be more efficient in catalysing is the PH level, which is a measurement of acidity in a substance, if the PH level is too high the rate the Enzyme can work decreases, and if the PH level too low, the Enzyme will also to be able to work at maximum efficiency. 
These changes in PH affect the Enzyme, since too low or high PH levels, change the active site of the Enzyme, sometimes it will still work but since the active site has been changed, how well the Enzyme can fit into the substrate will be worse.

Our bodies work best around 7 PH, but our stomachs work best around 2 PH since the insides of our stomachs are extremely acidic.

The National Grid

The National Grid is the network that distributes all the electricity in a city, usually the power comes from power stations, which normally produce lots of heat that then becomes thermal energy which then is turned into electricity.

The thing about power stations is that the amount of electricity they make is based on the amount of demand, the demand increases in the afternoon and evening, and since we use so much electricity in our daily lives, the power stations need to have extra capacity just in case, so often the stations run at much lower rate so that if there's a spike in electrical consumption they can output more power to satisfy the demand, which they can't do if they are running at high rates.

As we know the equation P=VT is power = voltage multiplied by time, but when high amounts of current flow through a wire, it causes the wire to heat up, this heat is then lost power, but if we need to transport this power all around the city or even the whole country this loss of power is extremely decremental.
But if we run a very low current, which is more efficient that would mean our voltage is going to be very high, meaning when we want to move the electricity around the country via the power lines and pylons we would need a way of increasing the voltage.

This is where Step-up transformers come in, they take the voltage from the power station and then turn up the voltage up to 400,000 volts then the cables transport it around the country.
Then after that, we would need a step-down transformer since 400,000 volts flowing into your house is too much if we were to pump that amount of voltage into a civilian house, firstly it would be very dangerous as if our devices or appliances they would explode having a high chance of losing lives.
In order to keep us safe from the high voltages is that we use a step-down transformer, that turns the 400,000 volts to roughly 230 volts. 

Ionic Compounds

Ionic compounds are different from ionic-bonded atoms.

As normal ionicly bonded atoms, they will lose their electrons and another element will gain them, causing the two atoms to be electrostatically attracted to each other. However, ionic compounds, have more than two atoms bonded together.

When this happens, the atoms will form in a sort of checkerboard pattern. If many atoms bond like this, the compound will be cube-shaped, which we named 'regular lattice structures." These structures will often be drawn or depicted as the cube shape. Still, with small spheres on its surfaces, another way we can depict this is we use a diagram named the "ball and stick diagram", which are similar but they instead draw or model each atom connected via a stick.

Something interesting about ionic compounds is that they have very high melting and boiling points, and they can conduct electricity, but most of the time we have to dissolve them in water or melt them down for electric conductivity, like putting salt in water to make the water more conductive, but what matters is the amount of charged particles

The boiling and melting points change depending on the strength of the bonds of atoms held together, and if the bonds in ionic compounds are very strong, more energy is required to break apart the bonds.

But if you want the ionic compound to conduct electricity, it first needs to have charged particles, if you take any solid it will be tough because all the bonds are stagnant, but if it melted or dissolved then the ions in the solid are free to move and conduct. 

In ionic compounds, one element would have to lose and one would have to gain an electron, for example, if you wish to write aa Sodium bonding with a Chlorine atom, which the Sodium has a +1 charge while the Chlorine has a -1 charge. 
So to have them bond, the Sodium would lose the electron while the Chlorine would gain one, thus, you would write this equation as NaCl+.  

But what happens if the atoms need more electrons to bond, what about Magnesium and Chloride, Magnesium needs to lose 2 electrons since it is in group 2 of the periodic table.
So the Magnesium loses 2 electrons to be a 2+ ion, then we need to balance it out, so we must take two Chlorine ions since one ion is only a -1, so if we were to write this out it would be MgCl2. 

Complex compounds like Calcium Hydroxide or Aluminium Sulfate are, more complicated as these ions aren't single elements so their atomic numbers or electron amounts are not on the table.

Instead, we will have to memorise it, for the Calcium Hydroxide is OH-, while the Aluminium Sulfate is SO42-.
Now we can look at the elements by themselves, Calcium is group 2 of the periodic table which means that Calcium or Ca has a +2 charge, while hydrogen is a -1 charge. 

Similar to the Chlorine atom, a single Hydroxide has a -1 charge, which means we need to put two of them in the CaOH- equation instead of one, the written formula for this is:
Ca(OH)2.
The reason why we put the 2 outside the brackets is because it means whatever is inside the brackets there is 2 of them. 

Now to tackle the Aluminium Sulfate, the Aluminium has a +3 charge, while the Sulfide ion has a -2 charge, this makes it a little bit more complicated because when two compounds bond they need to have the same amount of electrons.

But the problem is we can't add another electron to the Sulfate, in order for this to work we would need to first find the lowest multiple of both of the charges, which 3*2 is 6, so six is the smallest multiple we can find. 

So in order for this to work out we need 3 * 2 to get us 6, which we will take two Aluminium both of which are +3 charge, and three Sulfate ions, which means we have our 3 * 2.

So we would write this as: Al2(SO4)3. 

That's how we would write it, as we need 2 Al atoms the smaller scale 2 is there, then there is the SO4, which means the chemical writing for Sulfide, then the small 3 at the end means that there are three of the Sulfate ions. 

Other ionically bonded compounds are: NO3- for a Nitrate ion, a carbonate ion which is CO3^2-, and lastly is the Ammonium ion which is NH4+. 

Enzymes

For living organisms to survive, they need to carry out chemical reactions, which are often very slow, so to speed them up we normally apply heat to quicken the reaction.

Now, using heat has its side effects. If we use too much heat, the cells might get damaged, and it might also speed up reactions that we don't want.

In chemical and biological applications, Catalysts are substances that increase the rate that something happens and are not used up or changed,
Enzymes are biological catalysts made by living organisms. They are proteins, which are long chains of amino acids that can bend and fold, making them unique.

Enzymes work by taking a large structure, which we call a substrate, and breaking it down into smaller structures named products.
They can also do it in reverse, where they convert products into structures.

They also have a special region in them, which they can specify what they want to catalyze, and if the substrate doesn't match the catalysts, then it won't help catalyze the substrate.

There are two ways scientists thought it worked one way is the lock and key model, and then the induced fit model.
Before we figured out the induced fit model, we thought the catalyst needed to fit perfectly to the substrate being a 100% perfect match both ways, similar to what a lock and key is where the key has to be the same in order for the lock to open.

We do know now what the Enzyme will slightly reshape itself in order to help the substrate fit better, the Enzyme 'compliments' the substrate by fitting better, 

Parallel Circuits

Parallel circuits are circuits that have more than one loop, unlike series circuits, and each loop only has one component, making it more stable, meaning that if one component breaks, the whole circuit won't stop working.
We can also mix and match parallel and series circuits to add more components, an example of this is adding an on/off switch in the series circuit, which is connected to a parallel circuit.

Somthing different about parallel circuits is that since that all the compdennts get the same amout of potemntal difference, if we have a a parallel circuit with two compodents  on two loops and if the total amount of voltage going through the circuit is 4a, then either both compodents have the same amount of voltage taken (2a & 2a) each or they have an odd number like 3 & 1, if we add all of the amps in a circuit it should total to 4 reguardless. 

Eletricity likes to take the path of least-resistance, thats why electrical currents are stronger the lower the resistance the compident is, and the more compodents you add to a parallel circuit the lower the total resistsance will be,.

Ionic Bonding

As we know, atoms can bond together via ionic bonds, which happen when two atoms share the Valence electrons, which are the electrons on the outermost shell. 

Ions are created when an atom loses or gains an electron, this helps the atom to become stable, by having a full outer shell.

If we take Chlorine, which has 17 electrons in its shells and needs only one electron to form a Chlorine ion, the Chlorine atom will take that electron from another atom for example a Sodium atom or Na , which we write like this Cl+e- = Cl-.

But these don't happen by themselves, as the elections need a type of

Levels of Organization

The level of organization on the human includes: Organelles, Cells, Tissues, Organs, Organ Systems and Organisms.

Organelles are subcellular structures, things that are subcellular are Ribosomes, Mitochondria and the Nucleus.

And combined they make cells, which are all different, skin cells, blood cells, brain cells, these are specialised cells, which the scientific names of these cells are, Muscle cells, Glandular cells, and Epithelial cells. 

Next are tissues, these are groups of cells that work together to carry out functions like scar tissue, which is meant to cover up wounds to help them heal by shielding the wound from external sources, the epithelial cells combine together to make human skin along with the inside of our intestines.

The muscle tissue in our ligaments helps our body to move and flex, allowing us to grip things.

It also helps create chemicals and enzymes, like sweat, to cool our bodies and saliva, to help us digest food.

Next are our Organs. Once again, the tissues combine to make a larger structure, for example, the stomach, which breaks down food into proteins. Other things that tissues make are the lungs, teeth, bones, the digestive system and much more.

The organ's job is to 'carry out functions', which is similar to tissues, but can carry out larger processes compared to cells or tissues. These organs make systems like the Respiratory system, the Cardiovascular system, and the Reproductive system.

Then to make the whole organism, as you would need all of the organism's cells, tissues, organelles, organ systems and organs to make a functioning human body.

 

Foundation of ions.

Ions are charged particles, certain particles can form ions better than others, the reason why some elements want to become ions is because they want to have full outer shells to become stable molecules.

Elements need energy to lose or gain an Electron, so the fewer electrons an element has, the easier it is to lose them, for example, group 1 elements or the Alkali metals can lose their electrons very easily to become -2 ions.
Like group 6, which only needs to lose 2, and group 7, which only needs to gain one, groups 3-5 need to lose 3 electrons, making it harder for them.

We can depict these ions in equations, for example, an equation may look like this:
Na + e-.
This depicts a Sodium atom becoming a Sodium ion.

Cl + e- = Cl-.
This depicts a Chlorine atom becoming a Chlorine ion.

Now something to keep in mind is that when an atom is losing electrons and becoming a positive ion, then we put the electron on the right of the equation.
But if we put the electron on the left of the equation, it means the atom is combining with the electron to.

If an atom loses or gains multiple electrons, like an element like Magnesium, so we would write something like: Mg^2+ + 2e-, so this means Magnesium + 2 electrons.

Nicaragua

The country is named after the Nicaraguan tribe and Agua, which is the Spanish term for water.

Located in Central America, it is a bi-coastal nation with coasts on both the Caribbean Sea and the Pacific Ocean, located under Honduras and Costa Rica.

The border between Nicaragua and Costa Rica is just enough so that Costa Rica doesn't get access to lake Nicaragua, which is named after the countries named after, the narrowest corridor is only 2 miles wide or 3.2km, then on the border of Costa Rica they take the whole Portello lake even though it is fully enclaved in Costa Rica.

The whole country is split into 15 departments with 2 autonomous regions, their capital Managua, directly below Lake Managua or Xolotan, which is where the largest airport is, Managua's Augusto Cesar International.

Around 89% of the population lives in the south-western part of the country, the main highway, number 5, which ends in Puerto Cabezas, connecting to the Caribbean coast.

The port of Corinto, which is their largest port, often handles all the shipments. The west of the country is an uninterrupted coastline, with the east side being where all the offshore islands are.

Such as the Cayos Miskitos Biological Reserve, and the Corn Islands, strangely, the two islands beside the reserve, the Providencia and San Andes islands, belong to Colombia.

They also have territorial disputes with the USA over the island of Bajo Nuevo and the Serranilla Banks islands with Brazil.

There is also an island named Isla Calero that both Nicaragua and Costa Rica wanted to own. But then in 2016, the International Court of Justice ruled that the island belongs to Costa Rica.

Since Nicaragua doesn't have postal or street codes, they often describe where they live via landmarks and signs. And often the landmarks don't even exist anymore, so things can get confusing. They also have a unit of measurement named 'Vara', which is 84 centimetres.

They did make a rail system in 2001, but it was discontinued.

Some sites of interest include:

The National Museum, the Ruins of León Viejo, the León Cathedral, the historl city of Granada, the Masay craft market (they sell lots of hammocks), the cliff carving of El Tisey, the Revolution Museum, cigar factories, the Zapadera monoliths and petroglyphs, Apoyo lagoon, the Matagalpa chocolate factory, La Maison du Chocolat (a chocolate spa), the Casitta volcano memorial, the San Jacinto mud pools, the Cayos Miskitos stilt houses, the city of Esteli, and you can sand-board down Cerro Negro which is the youngest volcano in latin america.

They have a lot of volcanoes, as they are on the Ring of Fire, sandwiched between the North American plate and the Cocos plate, this gives Nicaragua a 'volcanic belt' which is a belt of volcanoes around the whole country, mainly dotting the south side with around 19 being active, the biggest being Sann Christobal.

Lake Managua or Xolotlan, which is the smaller one, and the largest lake, Lake Nicaragua or Cocibolca, which is the biggest lake in Nicaragua and in all of Central America.
There are many volcanoes between these lakes.

The largest two are Mototombo and Apoteque, situated near Managua, and there is Omotepe, which is an island made from the two volcanoes Maderas and Conception, situated in the middle of Lake Nicaragua.

Lake Nicaragua strangely drains to the east, flowing into the Caribbean via the San Juan river, even though the lake is roughly 10 miles from the Pacific Ocean on the west coast, while the Honduras Rio Grande De Matagalpa.

The county is divided by three regions, the Pacific lowlands which has all the volcanos and where Lake Nicaragua is, then the North Central highlands with tallest peak in the country, Mogoton, and the finally the Caribean lowlands which is near the Caribean sea and dense rainforests and near the coast is where there are swampy wetlands, and is where the most rain happens with around 635cm or 250 inces of rainfall.

Masaya volcano constantly has bubbling lava, Samoto canyon has lakes and small rivers flowing throughout the canyon, and unfortunately, Lake Managua has a pollution problem with the area around it covered in garbage.

The sad thing about Nicaragua is that it ranks as the second poorest nation in the Western hemisphere after Haiti, when you compare their nominal GDP and GDP per capita, around 40% of the population lives off a dollar a day, with 15% of their money is sent via family members that work abroad.

They are a part of the IMF, the indebted countries that help poorer countries, and they have the lowest energy generation in Central America, using oil and generators for electricity, which caused them to have an energy crisis in 2006.

But the World Energy Council has dubbed Nicaragua the world's most geothermal energy potential country, since 10% of its energy is made by volcanoes and heat.

They also have lots of animals here, including bats, jaguars, primates, along with the national bird, the Turquoise-browed Motmot.

Some food that is made and enjoyed here are: Frittinga (fried street food), Quesillo, Indio Viejo, Rondon, Chancho con yuca, Naca tamal, Vaho/Baho, Sopa mon Dongo, Pinolillo drink, Vigaron and Gallopinto.

In Central American states, they have nicknames: the Costa Ricans are Ticos, Salvadorians are Guanacos, Guatemalans are Chapin, Hondurans are Cathrachos, and Nicaraguans are Pinoleros.

They also have a saying, "Soy puro Pinolero; ¡Nicaragüense por gracia de Dios", which means "I am totally Nicaraguan Pinalero by the grace of God".

With a population of 6.824 million people, and with one out of six Nicaraguans living in either Costa Rica or the USA, the population is around 69% Mestizos, with 17% whites with Spanish heritage, with around 9% being in the black community, and the last 5% being part of the Indigenous Ameradianian groups.

Their current is the Cordoba, they use the type A American style plug outlets and they drive on the right side of the road.

They have very diverse people groups, mainly due to their colonial past, from people like Christopher Columbus to French pirates.

They have the largest population of people of African descent in Central America and most live on the Caribbean coast, most of them were brought by the British during the colonial times when the Brits colonised what was then called the Miskito coast which is named after the Miskito tribe which inhabited the area, the people living there are now named the Garifuna tribe.

Their language is English or a type of English Creole, but their National language is Spanish.

Around 20 Indigenous groups with them being the Rama, Miskito or Sumo tribes, mainly coming of Aztec or Mayan descent, also cuss and use lots of curse words, strangely enough, they have the lowest homicide/murder rate in Central America (6-7 per 100k) and are very safe to travel around.

They are Roman Catholicism at around 58%, then about 1/3 are protestant and during conflicts are disrupted the Catholic church will act as a mediator, the religion of Nicaragua is a vital part of their identity along with their traditions like the colourful clothing of the Mestizaja costumes, they are good poets which they also have lots of folklore, some nice, some creepy like the La Carretangua.

Weirdly enough a lot of the stories incorporate women, mainly ghost women like the La Ceuga, La Llorona and La Mocuana, diverting from their folklore, they also have a celebration called El Güegüense, which is on the Unesco Heritage list as an intangible heritage performed with masks and large costumes, this celebration is celebrated at the feast of Saint Sebastian.

Nicaraguans also like baseball instead of football or soccer, and their national hero, Dennis Martínez, is the first Nicaraguan who played in the MLB, with many more following suit.

The rough history is: The Native tribes in the country, Chistopher columbbus arrives and then the Spanish empire, Francisco Hernandez de Cordoba founded the first city, September 15, 1821 which is their independence from Spain, annexation from the first 1st mexican empire, then in 1823 part of the Federal Republic of Central America then 5 years later it git disbanded, then Nicaragua becomes a full country without a coloniser, then small civil wars, then Americam William Walker tries to take over the country then gets execuited via firing squad, then the Britsh relenquish the mosquito coast, then the USA occupies Nicaragua which then creates Santino's Armty which causes the Americans to leave, the Somoza Dynasty, the Sandista revolution in the 1960s-70s, they become more communist, then in 1990 they allect the first Female presedent, then the ecomony starts to recover, then Sandista party returns thing become slighty heated due to theor past then after awhile the economy starts growing more, then protests agebst the government.

Some people of Nicaraguan descent or with Nicaraguan heritage are: Augusto Cesar Sandino, Arlen Sui, Violeta Chamorro, Ruben Dario, Daisy Zamora, Eddy Kühl Aráuz, Luiz Enrique Hernaldo Zuñiga, Tony Meléndez, Salvador and Katia Cardenal, Bianca Jagger (Mick Jagger's first wife), Michelle Richerson, Alexis Arguello, Michelle Richerson, Alexis Arguello, Román Chocolatito González and Claudia Poll.

Some countries that have close ties with Taiwan, South Ossetia, and Kasnia, Taiwan helped them by giving them a 100 million dollar loan during the protests, which the President Ortega accepted. 

Although the USA has some rough patches with Nicaragua, they are still the largest import and export partner, and the US has the largest community of Nicaraguans in Miami.

Cuba, Venezuela and Bolivia have an alliance with Nicaragua named the "Alianza Bolivariana Para Los Pueblos De Nuestra America" or the Bolivarian Alliance for the People of our America; they all support the ideas of Simón Bolívar and socialist based governments. Cuba provided grants and development funds during the 70s and 80s, Venezuela provided Nicaragua with Oil.

Other Central American countries share an Independence Day on September 15. In 2006, they signed the CA-4, the Central America 4 Free agreement, which allows free movement between Honduras, Guatemala, and El Salvador.

Specialised Exchange Surfaces

These types of exchange surfaces are parts of an organism that exchange substances with the exterior envorment. 

Our exchange cells in our bodies are the Villi, and the Alveoli.
Its job is to exchange Oxygen and Carbon dioxide in our blood, but the Villi, which are our intestines, help with absorbing glucose and amino acids.

The roots in the bottom of the plant have their root hair cells, which help absorb the water in the surrounding soil, along with the leaves, to help them absorb CO2  in the air.

Something to help with these exchange surfaces is a large surface area, so by having hundreds of millions of Alveoli in our lungs, it makes it a larger surface area, having a large surface area increases the amount of diffusion and can also help with the diffusion rates. 

Another thing about diffusion surfaces is that they are often very thin because it makes the substances diffuse over a short distance, for root hair cells, the water only has to diffuse through a thin cell wall and membrane,
this is known as a 'short diffusion distance', which increased the speed with which the plant can absorb. 

Other types of diffusion surfaces are blood, as the blood has to flow and diffuse throughout the body, so having glucose dissolve into the blood that gets taken away to the intestines to then be replaced by more blood.

Another good thing to keep in mind is a 'good supply of external mediums', a good example of this is keeping a good supply of Oxygen for your lungs, when you breathe the Oxygen mixed with the Alveoli, which helps keep a steady concentration gradient for your bloodstream.

Series Circuits

Learning the difference between Series and Parallel circuits is important. 

In series circuits, the components are added in 'series' or in one line, as if they were all on one wire. The thing about this type of circuit is that if the wires break, the whole circuit stops working.
This also means that the potential difference is shared throughout the circuit.

You might get an equation like this :
Vtotal = V1 + V2 + V3.

If we were to put a 12-volt cell or battery, and have two filament lamps on the circuit, both lamps have to add up to 12 volts

On the other hand, current is the same everywhere in the circuit. To measure it, we use ammeters, which are placed in series, and since they measure current, we can place them anywhere in the circuit.

Resistance is how much the component resists electricity, and the total resistance is a sum of how much all components resist, so to calculate the resistance in ohms, we need to know how much power our components resist. 

So, let's take a circuit and connect two filament lamps, one lamp requires 4 ohms, and the other requires 2 ohms.
The total amount of ohms is about 6 ohms, since it is 2 + 4.

Let's use the same 6 ohm circuit above and calculate the resistance of a single component.
We can use the equation "V=IR", which is named Ohm's law, the 'V' in the equation means voltage.
So, first we find the battery, which is 12v or 12 volts. 
We then divide the 12 volts by 6 because that's how many ohms are flowing into the circuit, to get 2A or two Ammeters, then which then means that the component had 2A of resistance, then we multiply the 2A by 2 ohms or 2*2 to get 4 volts. 

Something to keep in mind is that Ammeters do have resistances, it is such tiny resistances that we can practically ignore them, now if we want to get the voltage of the second component, we would need to do the equation again, or we could just do 12-4 to get us 8.

Because we know how many volts are flowing through the circuit, which is 12, we can just skip doing the math, so doing 12-4 gives us 8, so that means that the second component needs 8 volts.

There is another way to find out how much voltage each component uses in the circuit by using a Voltmeter, which is connected in parallel to the component which we want to check, so if we connect it to the 8 volt component, it would display 8v.

Keep in mind that even though the voltmeter is connected in parallel,
we still consider the circuit to be in series, also the components that have a higher resistance will require more voltage, than components that resist less.

 

Group 7 & Group 0 (Halogens & Noble Gases)

 Halogens are very dangerous, these are the Halogens:

Florine is a poisonous yellow gas and is very reactive.

Chlorine is less reactive than fluorine but is a poisonous green gas.

Bromine is a dark brown liquid, once again the odour and liquid are poisonous, and the vapour that it creates is heavy, so you can pour out its vapour from a glass ampule

Iodine is a dark purple solid that forms poisonous purple vapours, but it is also a commonly used antiseptic in medical applications. 

Tennessine.

Atatine.

But we will mainly talk about the elements starting from Florine to Iodine, but the elements Tennnessine and Atatine are still important to remember.

All halogens exist as pairs of atoms, referred to as diatomic molecules. This term indicates that these molecules consist of two atoms. They form these pairs by sharing electrons through covalent bonds. Additionally, halogens can bond with other non-metals, such as carbon or hydrogen, using the same covalent bonding mechanism.
Chlorine bonding with Carbon can get you Carbon Tetrachloride.

Unlike the Alkali metals, the Halogens increase their boiling and melting points the further down you go on the chart.
Along with the boiling points increasing, the reactivity decreases, making the elements less reactive.

The reason why they become less reactive is because the electrons get further from the positive nucleus.

When Halogen ionic bonds with metals and collects an electron to become a minus -1 electron, we call those Halides, so we change the 'ne' at the ends of the names of the Halogens so when Bromine bonds with a metal it becomes Bromide, Iodine becomes Iodide, Chlorine becomes Chloride, and Fluorine becomes Fluoride.

Most of the time they bond with the Alkali metals, an example is Sodium Chloride, the Sodium is an alkali metal while the Chloride is a Halogen.

Another thing that Halogens do is that they do something called 'Displacement Reactions', which means that the more reactive Halogen displace the less reactive ones.

So if we pumped some Chlorine gas into a solution of potassium bromide, so the chemical numbers would be Cl(g) + 2KBr (aq), since Chlorine is more reactive than Bromine, it will displace the Bromine causing the element to become 2kCl(aq).

Something to keep in mind is that more reactive Halogens will always displace less reactive ones.

Helium.

Neon.

Argon.

Krypton.

Xenon.

Radon.

They are named the Noble Gases, these are special because they have full outer shells, causing them to be inert and being unreactive, along with that, they are non-flammable and their boiling points increase the further you go down. 

 

Surface Area to Volume Ratio

If we take a look at smaller organisms, something to take notice of is that they can use diffusion to exchange substances with their environments.
If we look at humans, we need specialised systems for transport via the heart and blood vessels, like our intestines and lungs for breathing and expelling waste.

The single-celled organisms have to constantly be doing chemical reactions to survive, like gathering amino acids, glucose and Oxygen, and getting waste like carbon dioxide out.

Everything has a Surface area to Volume ratio, for example, a cell has a higher surface area to volume ratio than a cow, as when organisms increase in size, the surface area to volume ratio decreases.

Now calculating this kind of thing is a bit confusing for organisms, instead we will use a small 1cm by 1cm by 1cm cube.

To calculate the surface area, you must first get the length and the width of one face, and multiply them together, so 1cm*1cm is 1cm^2 or 1cm squared, then you multiply it by 6 because a cube is six-sided, to get 6cm^2.
To get the volume of the cube, you need to multiply three values, which in this case is 1cm*1cm*1cm, to get 1cm^3, or 1cm cubed.
So at the end it has a ratio of 6:1, because it is six times bigger than the volume of the cube.

Now if we take another cube and instead of it being 1cm*1cm*1cm, it is 2cm, first we take one face of the cube and multiply it by its height and width (2cm*2cm), then which gives us 2cm^2, then we multiply it by six because six-sided cube then we get 24.

Then the volume is 8, by multiplying all the values 2cm*2cm*2cm, giving us 8cm^3 or 8cm cubed, so putting it into an equation would give a ratio of 24:8, which we can simplify by dividing both equations by 8, which gives us a ratio of 3:1.

The Indus River Valley civilizations

The early civilization came from the river valleys, known as the Harappans, this civilization was in the area of modern-day Pakistan in the Indus Valley, dating as far back as 7,000 BCE.

Around 3,300 to 2,000 BCE, the early Indus Civilization appeared, and that's when the Acadians and the Sumerians began interacting, and then around the 3rd millennium was when the empire of Sargon the Great was established.

Then around the mature period, which is around 2600 BCE, is where most of the advanced structures were found, and if we go to Egypt, around 2500 BCE is roughly when the Pyramids were built.

Then around 1600 BCE is considered the late Indus Valley civilization, which is where the Babylonian empire was founded.

The Punjab region in Pakistan is where most of our archaeological dig sites are about the Indus Valley Civilization, found around Harappa, which is why it is known as the Harappan civilization too, the largest site is Mohenjo-Daro in the Sindh region.
We believe that over 40,000 people were living in that region alone, with around Harappa and Mohenjo-Daro, there are over 1000 sites scattered all around both regions.

The reason why we think that this is a civilization is because of the sheer size of it all, the standardization of measurement and weight, we have found them using a measurement of 1.6mm which is precise, we can speculate that there was some cultural interchange, sin they were using bricks that were a standard size so measurements were needed.

In Mohenjo-Daro, we found some sites that these people lived in, from citadels, to public baths, and what was impressive is that we found sewerage systems for carrying waste, along with houses with wells.
Their jewellery is intricate and complicated with shells gathered from the Arabian Peninsula, and the type of jewellery was not only found at these sites but also in Mesopotamia too, and we speculate that there were probably ships transporting cargo from Mesopotamia and the now modern-day Mohenjo-Daro region. 
Materials from what is now modern-day China and India, they also had their own writing system and they also made Symbols along with a wee known symbol of a Nazi Swastikas', before Hitler used in his campaigns it is a common symbol in Hinduism, often meaning good luck,.
But we don't really know much about them, other than the stuff we found at dig sites, and since we can't decipher their writing.

One of the strangest things about the Indus Valley Civilization is 'why did it end', they seemed to be thriving with good ties and imports from other civilizations, some ideas on why it ended were maybe they were invaded, some other theories are that it was because of climate change.

As one of the earliest civilizations on earth, with speculation that their whole population may reach 5 million, they used bricks and drainage systems for sewage, non-residential buildings, and water systems.
The civilisation started declining around 1800 BCE, and the drains and waterways started to become clogged, their writing started to fade, and the weights used in measuring were starting to fall out of use.   

Around 2600 BCE, is when the early Harrapan civilization started developing urban centres, the cities of Harappa, Ganeriwala and Mohenjo-Daro in what is now modern-day Pakistan.
And Dholaviva, Kalibangan, Rakhgarhi, Rupar and Lothal in modern-day India, in baths and the sewage systems they used, fire-baked bricks since they can hold up to moisture.

Around 23,000 people lived in Harappa, which we know was a fortified city along with the religious and government centres in what is modern-day Pakistan,
The houses were built of red sand and clay, spanning over 150 hectares, which is 370 acres.
The cities had citadels, which were at the centre of the civilization. Since the Indus River had elevated areas, the Harappans fortified them to have a large, bird's-eye view of the whole area. 

Along with the expansive sewage system they made, and the public baths, we also found they had garbage collection, and they also also had a high regard for spiritual piety and hygiene. 

With their advanced architecture, they built dockyards, warehouses, granaries for grain storage, and large walls to protect them from invasions and floods.
Strangely, unlike Ancient Egypt and Mesopotamia, they did not build large structures or monuments. 

Because the standardized bricks were all the same size, we assume that they did make a measurement system of sorts. Because the bricks were uniform, we can tell that their sphere of influence was big due to the spread of civilization.

They are the first civilization that we know of that made sewage and plumbing systems, what's interesting is these systems made during this time are more effective and advanced than some 3rd world countries.
Some homes drew water from wells, and all the houses were connected to the sewage system, even the houses on the outskirts of the city, this evidently means that they had high regard for themselves to be sanitary and clean.

The Harappans also did seal making, which was used in stamps to mark goods, carvings like water buffalos, tigers and elephants were artefacts found by archaeologists.
They also made strides in metalwork, with metals like Tin, Copper, Bronze lead, and others, they also used a semi-rare gemstone, Carnelian, which is dark orange in colour, which they used in jewellery.

The Harappans also traded maritimely with others and had a trading network spanning the Middle East to central Asia. They also may have been the first to use wheeled carts pulled by oxen, and they also did shell work with their maritime imports from what is now modern-day Oman.

The majority of their imports are from places like modern-day China for jade, and India for copper and lead, they mainly traded pottery like terracotta pots, sea shells, precious metals and coloured gemstones like lapis lazuli and turquoise, pearls and jade.

They were a part of the Chalcolithic period, also known as the Copper Age, which is around 4300 - 3200 BCE, which showed an uptake of making more pottery that was very similar to the pottery by the Harappans, Turkmenistan and northern Iran. 

Then there is the early Harappan period, which is around 3200 -2600 BCE, and there are many similarities with other civilizations in their culture, By way, they make their seals and use them to mark goods, along with mystical animals like unicorns.

We also found a seal depicting Mohinjo-Daro, a half-human, half-buffalo monster fighting a tiger. This might symbolise the fighting of Gilgamesh, a known folk hero in Mesopotamian poems, and Aruru, the Sumerian earth and fertility goddess.

When we excavated these sites in the Indus Valley, we saw the art and culture of the Indus Valley civilisation, sculptures, and figures made from bronze, terracotta, and steatite.
Along with gold jewellery and a head of what we presume to be a priest wearing a robe, we have also found another statue of what we have dubbed the dancing girl. It looks like a girl with one hand on her right hip. We have also found other terracotta sculptures, including animals like bears, cows, and monkeys. 

We also know they were very organised, due to their hierarchies, their evenly sized and spaced out bricks, their seals and weights are well balanced and were similar in weight, with everything so uniform and well balanced we know that there was a kind of central government or governing body making sure it all of them were correct and proper.

Several theories say what kind of governing body they had, some say it was a central governing state, and some say that the whole thing was similar to a state-controlled area.
Meaning that the whole thing was organised by one governing body, sign that this might be true was that there was evidence that there were settlements that were nearby raw materials and similar artefacts.

There is another theory that states that the Harappan civilization had a group of leaders each governing their respective region, instead, the theory is that there is no centralized state, other people have theorised that there was no central government and everyone was considered an equal. 

We have found some written materials that gave us great insight into the Anchent Mesopotamian and Egypt civilizations, but unfortunately, since the script is so difficult to decipher the script compared to the Egyptian script Hieroglyphs which we already figured out how to read, the Indus scripts are still a mystery to us, because we can't understand the script, other than finding artefacts, the majority of our knowledge on it is purely either guesswork or with deducting what they did via clues like the fact we know they traded with others, and were sea-faring people.

We also have not come across any elite burials, meaning no graves we have found that looked to be the tomb of a king or queen or someone with high status, maybe its because they believed in a different afterlife, or didn't believe in any at all.

But this doesn't rule out the social hierarchy, as we have found that there were differently sized houses, often meaning the bigger the house the more socially or economically the person was, along with the location of the house also symbolising the amount of wealth they had.

We also believe that the Harappans were not into much warfare as they were peaceful, at least we think so as we did find weapons at dig sites but we assume they did not involve themselves in war maybe because of their location or sheer population size.

The Indus Valley Civilization started its decline around 1800 BCE, some theories are that there was a great flood, climate change or the drying of the Sarawati river which hapened around 1900 BCE.
One other theory states that the large civilization broke  up into smaller communities  which we called them the late Harappan cultures. 

Another way they could had their decline was the moonsoons, which was maybe a detrement to their livestock and crops.

The theory that mkes the most sense is during 1800 BCE decline, the Indus Valley became cooler and dryer and a potental earthquake causing the rivers to be disrupted, and causing the Harappans to move since their form of water is non-existanent, they may have tried to go to the Ganges lake in the east, but since they had a large population and they wen't able to trade since of their lack of resourses, and slowly abandoned their civilization by 1700 BCE.

Components

Components are used in circuits for electricity to flow, and we write these components via symbols.

Firstly, we write multiple vertical lines to depict a Cell or Battery, which powers the circuit.

Wires are written as lines and normally straight, and they carry the current throughout the circuit.

A Fuse is a rectangle with a wire running through it. Its purpose is to prevent the device from being overloaded. When too much power flows through the circuit, the fuse breaks, cutting power.

For switches, it will look like two circles connected via a short line between them, when the line is connected it means the current can flow, but when the switch's line isn't it means the current can't flow.

Then a Diode is a component that only allows current to flow a certain way, a form of diode is a Light Admitting Diode or LED, which lights up when electricity flows through it.

Now, for measuring current, we have Ammeters, which are put in series or connected through the circuit, and Volumeters, which are used for measuring potential difference and are  added in parallel, usually outside the circuit.

Lastly, we have resistors, which 'resist' the current to a specified amount, certain components can only function at certain amounts of electricity, if we put too much power into a component it might fry the circuits and the components might smoke or catch on fire, for example, when you charge your phone, it has resistors in the plug to not take too much power so that the internals don't fry.
Along with normal basic resistors, there are also variable resistors that can be modified so that they resist more or less current based on the situation.

Light-dependent resistors use light as a way of varying the amount of resistance, if you put them in a bright environment will resist a lot less than in a dark one as the darker it gets the more they will resist an application many people use these LDR's is in automatic nightlights which turn on when the lights in the room are off.

Thermistors use heat to vary the resistance so the more heat the less resistant the resistor becomes, and the colder it gets the more resistant it becomes.