MATTER IS THE STUFF AROUND YOU! Not very clear, but it's true. Anything that takes up space or has a mass of any kind is matter. Everything you can touch is made of matter. If it is made of anything, that anything is matter. Everything you will learn about Chemistry will all be based on how matter reacts and combines. Matter has many properties. It can have PHYSICAL properties like different densities, melting points, boiling points, freezing points, color or smells. There are also CHEMICAL properties that define matter. A good example of chemical properties is the way elements combine with each other in reactions. The big thing to remember... Matter can change in two major ways, physically and chemically.

There are four main STATES of matter. SOLIDS, LIQUIDS, GASES, and PLASMAS. Each of these states is also known as a PHASE. Elements and compounds can move from one phase to another phase when special physical forces are present (* physical, not chemical *). One example of those forces is TEMPERATURE. When temperature changes, the phase can change. Generally as the temperature rises, matter moves to a more active state.


Phase describes a PHYSICAL state of matter. The key word to notice is physical, because things only move from one phase to another by physical means. If energy is added (like increasing the temperature or increasing pressure) or if energy is taken away (like freezing something or decreasing pressure) those are physical changes. Those kinds of forces change states of matter.

One compound or element can move from phase to phase, but still be the same substance. You can see water vapor over a boiling pot of water. That vapor (or gas) can condense and become a drop of water. If you put that drop in the freezer, it would become a solid. No matter what phase it was in, it was always water. It always had the same chemical properties. On the other hand... A chemical change would change the way the water acted, eventually making it not water, but something completely new.

SOLID BASICS
Solids can be made up of many things. They can have ELEMENTS or compounds inside. They can also be made up of mixtures, or combinations of different elements and compounds. Most of the solids you see are mixtures. Most rocks are mixtures of many elements and compounds. Concrete is a good example of a man-made solid mixture.

CHARACTERISTICS OF SOLIDS
First let's explain that characteristics are the traits or features that something might have. One characteristic of a solid is that it might be hard. That idea is pretty straight forward. One of the main characteristics of solids is that they hold their own shape. So if you put a solid in a container it won't change its shape... No matter how much you move or slide it around. You can even grind a solid up so that it fills up a container. If you look at the powder under a microscope you will still see little tiny solids that you couldn't change. You Know that liquids are different because if you put a liquid into a container it will fill it up as much of the container as it can. In the same way that a solid holds its shape the atoms inside of a solid are not allowed to move around much. This is a physical characteristic of all solids. It happens no matter how small the pieces are. The atoms in liquids and gases move around in all directions. The solid atoms and molecules are trapped in their places. The atoms still spin and the electrons still move but the entire atom doesn't go anywhere. They just kind of jiggle in place.

SO YOU WANT TO BE A SOLID
Obviously not everything is a solid. If you look around you'll see solids, liquids, and especially gases (remember the air around you). Sometimes liquids feel a physical need to become a solid. Then look out! Phase changes are about to happen. Scientists use something called a FREEZING POINT to measure when a liquid turns into a solid. There are physical effects that can change the freezing point. Pressure is one of those effects. When the pressure surrounding a substance goes up the freezing point also goes up. That means it's easier to freeze the substance at higher pressures. When it gets colder, most solids shrink in size. There are a few which expand but most shrink. If a solid is made up of pure elements or compounds something special happens. It can freeze into a very specific structure. This structure is called a CRYSTAL LATTICE. A crystal lattice is a very exact organization of atoms which creates a specific place for every molecule or atom in the solid. It is very neat and very compact. A great example of a crystal lattice is a diamond.

LIQUIDS BASICS
Liquids are an in-between phase of matter. They are right between solids and gases. One characteristic of a liquid is that it fills the shape of any container. So you pour some water in a cup. It fills up the bottom of the cup first and then fills the rest. It also takes the shape of the inside of the cup. It starts filling at the bottom because of Gravity. When it is in that cup it also has a flat surface. That's because of gravity too. One other characteristic of liquids is that they are very hard to COMPRESS. When you compress something you take a certain amount and force it in a smaller space. Solids are tough to compress too but gases are easy. When you compress something you squeeze it so the atoms in the substance are closer together. When pressure goes up... Substances are compressed. Liquids already have their atoms close together so it's hard to push them even closer.

SO YOU WANT TO BE A LIQUID
If you want to be a liquid you could start out as two different things. You could be a solid or you could be a gas. Each of them has a different way of becoming a liquid. Let's say you're a solid. That's you. A handsome cube of ice sitting on a counter. All you do is dream of becoming liquid water. What you need is some ENERGY. Atoms in a liquid have more energy than the atoms in a solid. The easiest energy around is probably heat. There is a magic temperature for every substance called the MELTING POINT. When a solid reaches the temperature of its melting point... It can become a liquid. For water the temperature has to be a little over zero degrees Celsius. If you were salt, sugar or wood your melting point would be higher than water. So solids need more energy. The reverse is true if you are a gas. You need to lose some energy from your very excited gas atoms. The easy answer is to lower the surrounding temperature. When the temperature drops, energy will be sucked out of your gas atoms. When you get to the CONDENSATION POINT, that's the temperature when you become a liquid. If you were the steam of a boiling pot of water and you hit the wall, the wall would be so cool that you would quickly become a liquid.

EVAPORATION
Sometimes a liquid can be sitting there and its molecules will become a gas. That's called EVAPORATION. You might be wondering how that can happen when the temperature is low. It turns out that all liquids can evaporate at room temperature and pressure. Evaporation is when there are atoms or molecules escaping from the liquid and turning into a vapor. You see... Not all of the molecules in a liquid actually have the same energy. The energy you can measure is really an AVERAGE of all the molecules. There are always a few molecules with a lot of energy and some with barely any energy at all. It is those with a lot of energy that build up enough power to become a gas and leave the liquid. When it leaves it has evaporated.

GAS BASICS
Gas is everywhere. There is something called the ATMOSPHERE. That's a big layer of gas that surrounds the Earth. Gases are random groups of atoms. There are solids where atoms and molecules are really compact. Liquids have them a little more spread out. But gases are really, really spread out and the atoms and molecules are full of ENERGY, bouncing around constantly. One of the physical characteristics is that a gas can fill a container of any size or shape. Think about a balloon for a minute. No matter what shape you make the balloon it will be completely filled with the gas. The atoms and molecules are spread equally throughout the entire balloon. Liquids can only fill the bottom of the container while gases can fill it entirely.

SO YOU WANT TO BE A GAS
We're betting that you want to be a gas right now. Actually you need energy to become a gas. The atoms in a gas have more energy than the atoms in solids and liquids. The easiest way to think of energy is to think of temperature. When you increase the temperature of a system you are pouring energy into that system. If you add energy to a liquid the atoms get all excited. When you boil water the steam you see is small water droplets being carried by the rising gas/water vapor. You can also find water vapor in fog and clouds. The special temperature when a liquid becomes a gas is called the BOILING POINT. When you cool a gas it liquefies. When a gas becomes a liquid the speed and energy in the molecules drop and ATTRACTION forces allow the molecules to group together. You might hear the term VAPOR. Vapor and gas mean the same thing. The word vapor is used to describe gases that are usually found as liquids (like water). A compound like CO2 is usually a gas, so it described that way. But water (H20) is usually found as a liquid at room temperature. So when it becomes a gas scientists use the term vapor.

PLASMA BASICS
Plasmas are a lot like gases but the atoms are different because they are made up of free ELECTRONS and IONS of the element. You don't really find plasmas too often when you walk around. They aren't something that happen regularly on Earth. If you have ever heard of the Northern Lights or Ball Lightning you might know that those are types of plasmas. It takes a very special ENVIRONMENT to keep plasmas going. Scientists say that they are the fourth state of matter. They are different and unique from the other states of matter.

SO YOU WANT TO BE A PLASMA
So imagine you're a gas. Floating around and you say "Hmmmm, I'd like to become a plasma. They are too cool!" You're already half-way there being a gas. But you need more. You need to tear off a bunch of electrons from your atoms. Eventually you'll have bunches of positively and negatively charged particles in almost equal CONCENTRATIONS. When the ions are in equal amounts the charge of the entire plasma is close to NEUTRAL. (A whole bunch of positive particles will cancel out the charge of an equal bunch of negatively charged particles.) Now you know what you need to have. The question is how do you make it happen? The answer is ENERGY! A plasma can be made from a gas if a lot of energy is pushed inside. All of this extra energy makes the neutral atoms break apart into positively and negatively charged ions and free electrons. The electrons are pulled off of neutral atoms. They leave ions and electrons in a big gaseous ball. And there you are. You are a big glowing ball of plasma running around and impressing your friends.

FINDING A PLASMA
We said you wouldn't find plasmas anywhere. But maybe there are some right in front of you. Think about a fluorescent light bulb. They are not like regular light bulbs. Inside the long tube is a gas. When the light is turned on ELECTRICITY flows through the tube. This electricity acts as that special energy and charges up the gas. This charging and exciting of the atoms creates a glowing plasma inside the bulb. Another example of plasma that you may have seen is a neon sign. Just like a fluorescent light, neon signs are glass tubes filled with gas. When turned on the electricity flows through the tube. The electricity charges the gas, possibly neon, and creates a plasma inside of the tube. The plasma glows a special color depending on what kind of gas is inside. You also see plasma when you look at stars. They aren't easy to find if you live in a big smoggy city. Look hard. Stars are big balls of gases at really high temperatures. The high temperatures charge up the atoms and create plasma. Stars are another good example of how the temperature of plasmas can be very different. Fluorescent lights are cold compared to really hot stars. But still... They are both forms of plasma.

ARCHIMEDES PRINCIPLE
In the third century B.C., a Greek mathematician named Archimedes made a discovery that answers why some objects sink and other objects float. According to Archimedes, water exerts an upward push on all objects. Just how much upward push is determined by calculating the weight of the object versus the weight of the fluid displaced. If the weight of the object is more than the weight of the fluid moved out of the way, the ojbect will sink. If the weight of the object is less than the weight of the displaced fluid, the object will float.

p r e s s u r e

All matter is made of particles and these particles are in constant motion. As each particle moves, it pushes against something. The "push" or force the particle exerts is called pressure. Perhaps you are familiar with the word pressure as it is used to describe water, air, and even blood. Pressure is an outward force and scientist describe pressure as force per unit area.

You are probably familiar with some important consequences of pressure. Many devices must be inflated to a particular pressure before they can operate properly. For example, a car whose tires are not properly inflated may not ride correctly. Think of a basketball not inflated properly. How does pressure move? Pressure always flows from areas of high pressure to areas of low pressure. Air in the atmosphere exerts pressure. It might surprise you to learn that air exerts a pressure on your body equivalent to the weight of an automobile. What keeps this force from crushing you? The fluids inside your body exert pressure, enough pressure to balance the outside air pressure. Notice the two cans, if air is removed from the can to the right, what would happen? Outside air pressure would be greater than the pressure inside the can. Pressure would move from high to low and the can would be crushed. Imagine an aerosol can of hairspray. The contents inside the can are under extreme pressure. When you mash the nozzle you are releasing some of the pressure. The contents flow from inside the can to outside the can, that's high pressure to low pressure.

Pressure is also influenced by gravity. When a submarine submerges below sea level, the pressure water exerts on the vessel increases as the submarine increases its depth. If the vessel goes to low, the pressure the water exerts could literally crush the submarine. The pressure the water exerts on the submarine is because of gravity. Gravity affects pressure in other ways. Have you ever stopped to think about what causes water to come out of the faucet. Its because of gravity's affect on pressure. Look at the diagram below:


(A) Water is pumped from the water treatment plant, (B) water is pumped through the (C) water lines, (D) whenever the pumping station cannot keep up with the demand, gravity helps flood the water lines.

Suppose you poke your finger into a balloon filled with air. What happens to the pressure you applied to the balloon? The pressure is transmitted, or sent out, equally in all directions throughout the fluid. This means the pressure is increased in every direction. This concept was discovered by Blaise Pascal and is known as Pascal's Principle. We experience this concept all the time. Hydraulic devices operate on Pascal's Principle. Hydraulic machines are machines that move heavy loads in accordance with Pascal's principle. Maybe you've seen a car raised using a hydraulic lift. A pipe that is filled with fluid connects small and large cylinders, pressure applied to the small cylinder is transferred through the fluid to the large cylinder. Because pressure remains constant throughout the fluid, according to Pascal, more force is available to lift a heavy load by increasing the surface area of the large cylinder. Look at the image to the right, and notice the increase in surface area. Notice a small amount of effort can lift a heavy object. How do you stop a moving car? Brakes of course, but did you know that brakes are hydraulic devices? A small amount of effort at the brake pedal is increased inside the brake drum.

Bernoulli's Principle
Imagine a world without airplanes. Traveling across the country takes several days, but it takes even longer to travel between countries. Foreign aid arrives at its destination too late, and meetings between government officials or businesses from different nations are rare. Everything you find at the grocery store is grown nearby. Luckily for us, there are airplanes today. And a lot of the credit goes to a mathematician named Daniel Bernoulli. For a long time, people have tried to fly. Again and again, plans failed because they couldn't get their planes up in the air, or if they did they couldn't keep them up. This problem is solved by Bernoulli's Principle. Bernoulli's Principle states that if the velocity (speed) of a fluid increases, the pressure of the fluid or exerted by the fluid decreases. Airplane wings are made so that the top of the wing is more curved than the bottom. That makes the air go faster over the wing. Air travels quickly over the wing, but it travels slowly under the wing. That means that there is less pressure over the wing than below it, because air is a fluid. Take a look at the diagram below and notice how more wind is force over the top of the wing, instead o fthe bottom.


As the airplane speeds down the runway, air rushes over and under the wings. As the air going over the wings goes faster and faster, there is less and less pressure above the wings. Soon there is much more pressure below the wings than above. This pressure pushes up on the wings and the airplane is lifted into the sky.

THE GAS LAWS
An english scientist named Robert Boyle discovered an interesting relationship between gases, temperature, and pressure. According to Boyle, if you decrease the volume of a container of gas and hold the temperature at a constant, the pressure of the gas will increase. Look at the diagram below and notice the pressure gauge:


the temperature remains the same yet the pressure increases. Why? Because volume decreased. Another aspect of what has become known as Boyle's Law is the behavior of a weather balloon. As you know, temperature and pressure decreases as elevation increases. What happens to volume? As a balloon rises, its volume increases. That's right, volume increases. A weather balloon can expand 30 - 200 its original size.

A French scientist, Jacques Charles explained another relationship between volume, pressure and temperature. What happens to the size of a balloon if you place it in a refrigerator? Its volume decreases right? According to Charles's Law, the volume of a gas increases with increasing temperature, and decreases with a decrease in temperature. Take a look at the animation below and notice the relationship between volume and temperature.

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