Everything around you is matter. Matter is anything that has mass and takes
up space. Matter can be identified by its physical properties. Physical properties
are characteristics that you can observe and measure. Some physical properties
that can be measured include mass, volume, and density. The amount of matter in
an object is its mass. Volume is how much space an object takes up.
Density is how much matter is in a given amount of space. Very dense things
are packed closely together, where less dense things are more spread apart.
Objects that are less dense than water will float. Other physical properties of
matter can be observed with the five senses. How an object looks, smells, tastes,
sounds, and feels are all physical properties.
Matter exists in three states: solids, liquids, and gases. A solid has a definite
shape and a definite volume. A solid’s shape and volume stay the same no matter
what type of container it is put into. The particles in a solid are packed closely
together. A liquid has definite volume, but no definite shape. The particles in a
liquid are spread apart a little, and they slide around each other. This allows a
liquid to take the shape of its container; but its volume always stays the same. A
gas doesn’t have definite shape or volume. Its particles are spread very far apart
and move quickly in all directions. A gas will spread out and completely fill its
container.
There are ways that matter can be changed. One change in matter is a
physical change. In this type of change the object is altered but a new substance is
not formed. Another change is a chemical change where a new substance is
formed by some sort of chemical reaction. A piece of paper being shredded is a
physical change. Freezing, melting, and evaporating are also physical changes. A
log burning and turning into ash is a chemical change. The digestion of your food is
also a chemical change.
When different substances are combined they can form mixtures or
solutions. A mixture is a combination of items where each retains its physical
properties. Think of a fruit salad where you can easily pull out the piece of fruit
you want. A solution is when items are mixed so evenly that they cannot be
separated. Once you mix Kool-Aid with water, you cannot pull the Kool-Aid mix
back out to separate it from the water.