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Changing Matter

Physical Changes

Physical changes begin and end with the same type of matter. Physical changes can be changes in size or shape, change in position or texture, and a change in state. The type of matter and properties do not change. Examples are an ice cube melting, cutting paper into different shapes or raking leaves. Water does not change its properties even if it is melted, frozen, or heated. Books and furniture cannot change state regardless of the amount of heat added to it.

Water can exist in more than one state. Water can exist as a solid, liquid, and gas. Taking away heat or losing heat causes matter to change from one state to another.
  • For solids, when heat is added to it, the particles vibrate more rapidly, and cause the solid to change to a liquid.
  • For liquids, adding more heat will cause the particles to move fast so that they break away from one another. Some particles may escape as gas.
  • For gas, particles move fast and adding heat makes them move farther and faster apart. An example is pond water that evaporates faster in summer because of the higher air temperature which adds heat energy to the surface water. This causes the particles to move farther apart and escape as gas.

Chemical Changes

Chemical changes are changes in matter. In a chemical change, matter has different properties from the one you started out with. A chemical change is also called a chemical reaction. Chemical changes involve taking in or giving off energy which maybe in the form of electricity, heat or light.
Some examples of chemical changes are the formation of table salt from sodium and chlorine. Also the formation of tarnish from a metal and oxygen. There are two products of a chemical change. The product is a compound or sometimes the product is the element making up a compound.
Chemical changes can be beneficial or harmful. Sugar is beneficial. Rust is harmful for a bridge especially when it can endanger cars and people from passing safely. To prevent some chemical changes, silver polish adds a protective layer to silver as it is cleaned.
There are some real-world chemical and physical changes. An example of a chemical change is toasted marshmallows. It occurs when oxygen combines with sugar, and carbon dioxide and water vapor is released. Another example of a chemical change is the browning of an apple. The oxygen in the air reacts with the exposed apple and results in browning. An example of a physical change is popcorn popping. The heat changes the popcorn kernel to gas and pressure builds up until the kernel pops.

Comparing Solids, Liquids and Gases

In this topic you will learn about three forms of matter: solids, liquids, and gases. Each of these three forms of matter takes up space and has mass.
A solid is matter that has a definite shape and volume. Definite means that it stays the same. If you put a sneaker in a container, it stays the same shape in the container as it had outside the container. Its volume stays the same, too. In a solid, the particles of matter are packed closely together. They form a certain pattern which gives the solid its definite shape.

Juice is an example of a liquid. A liquid is matter that has a definite volume, but not a definite shape. A liquid takes the shape of the container it is in. The particles in a liquid are close together but do not form a certain pattern. Particles in a liquid have more energy than particles in a solid. Particles in a liquid are able to slide past one another. That is why liquids change their shape.
Another form of matter is gas. A gas is matter that has no definite shape or volume. The particles in a gas spread out to fill a large container or squeeze together to fit into a smaller container. Gases take the shape of the container they are in. Air is made of gases.
Matter can change and still be the same type of matter. When you slice an orange, the orange may look different, but it is made from the same particles as before it was cut. Matter can also change form and still be the same type of matter. You can find water in the form of a solid, a liquid, or a gas.
When you mix different types of matter together, you may get a mixture. In a mixture, each part has the same properties in the mixture that it has outside the mixture. Air is a mixture of gases. Salad dressing is a mixture of oil and vinegar. One special type of mixture is a solution. A solution is formed when one or more types of matter are spread evenly throughout another kind of matter.

What is Matter?

Properties describe matter. A block of wood, milk, and air all have properties. All the material on earth is in three states-solid, liquid, and gas. The "state" of the matter refers to the group of matter with the same properties. In other words, you group the objects together according to their properties.

Solids
The wood block is solid. A solid has a certain size and shape. The wood block does not change size or shape. Other examples of solids are the computer, the desk, and the floor.
You can change the shape of solids. You change the shape of sheets of lumber by sawing it in half or burning it.
From wood to 
How might you change the shape of a piece of gum?


Liquids
Milk is a liquid. Milk is liquid matter. It has a size or volume. Volume means it takes up space. But milk doesn't have a definite shape. It takes the shape of its container.
Liquids can flow, be poured, and spilled. Did you ever spill juice? Did you notice how the liquid goes everywhere and you have to hurry and wipe it up? The liquid is taking the shape of the floor and the floor is expansive limitless boundary (until it hits the wall). You can't spill a wooden block. You can drop it and it still has the same shape.
What about jello and peanut butter?
You can spread peanut butter on bread, but peanut butter does not flow. It is not a liquid at room temperature. You have to heat peanut butter up to make it a liquid. When you or your mom makes jello, it is first a liquid. You have to put it in the refrigerator so that it becomes a solid. These are yummy forms of matter with properties of a liquid and a solid.

Gases
Run in place very fast for a minute. Do you notice how hard you are breathing? What you are breathing is oxygen? You need oxygen to live. That's why you can only hold your breath for a certain amount of time.
You can't see oxygen. It's invisible. It is a gas. A gas is matter that has no shape or size of its own. Gases have no color.
Gases are all around you. You can feel gas when the wind blows. The wind is moving air. Air is many gases mixed together.

Matter

Matter is anything that takes up space and has mass. Matter also has properties which can be observed. These properties are color, texture, shape, size, hardness, smell, temperature, magnetic attraction, dissolvability in liquid, and buoyancy. Buoyancy is the upward force of water or air that keeps things afloat. An example of buoyancy is a boat floating on top of water.

Mass is the amount of matter that makes up an object. It can be measured in kilograms and grams. A balance can be used to measure mass.

The three states of matter are solid, liquid, and gas. A solid has definite shape and amount of space. Examples of solids are a book, pencil, and desk. A liquid takes the shape of its container and takes up a definite amount of space. Orange juice, water, and oil are examples of liquids. A gas does not have a definite shape or take up a definite amount of space. Helium and oxygen are examples of gases.

Matter that is thrown away is buried in landfills, burned, or dumped in the ocean. Instead, we should be reducing the number of things that become garbage, reusing something instead of throwing it away, and recycling materials such as glass and boxes.

source: http://www.mhschool.com/science/2005/student/summary.php?isbn=0022812148&id=729&level1=E&level2=10&level3=1

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