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A basic introduction to the three primary states of matter found on Earth.
Have you ever wondered why an ice cube stays like a little brick, but the water it melts into slips right through your fingers?
Everything you see, touch, and breathe is made of matter. Matter is anything that takes up space and has weight. On Earth, matter usually shows up in main forms called states. These are solids, liquids, and gases. Even though they look different, they are all made of tiny pieces called particles. Think of particles like tiny LEGO bricks that are either glued tight, sliding around, or flying through the air!
Quick Check
How many main states of matter are there on Earth?
Answer
There are 3 main states: solids, liquids, and gases.
A solid is matter that has its own fixed shape. If you put a wooden block in a bowl, it stays a block. It doesn't turn into the shape of the bowl! This is because the particles in a solid are packed very closely together. They are stuck in place and can only vibrate or wiggle a little bit. Common solids include your desk, your shoes, and even the bones inside your body.
1. Take a pencil (a solid). 2. Place it inside a round cup. 3. Notice that the pencil is still long and straight. It did not become round like the cup because it is a solid with a fixed shape.
Quick Check
Why doesn't a solid change shape when you move it to a different container?
Answer
Because its particles are packed tightly together and stuck in place.
A liquid is matter that does not have its own shape. Instead, it takes the shape of whatever container it is in. If you pour milk into a square glass, the milk becomes square! The particles in a liquid are close together, but they can flow and slide past each other. Even though the shape changes, the amount of liquid (the volume) stays the same. If you have cup of water, it is still cup whether it is in a tall bottle or a flat plate.
1. Imagine pouring mL of juice into a tall, thin glass. 2. Now, imagine pouring that same juice into a wide, flat pan. 3. The juice changes from a 'tower' shape to a 'puddle' shape, but you still have exactly mL of juice.
Quick Check
What happens to a liquid's shape when you pour it into a new bowl?
Answer
The liquid changes its shape to match the shape of the bowl.
A gas is matter that has no shape of its own and will spread out to fill up any space it can. The particles in a gas are very far apart and move very fast in all directions. Most gases, like the oxygen we breathe, are invisible. However, you can feel them when the wind blows or see them when they are trapped inside a balloon. Unlike solids and liquids, gases can be squeezed into smaller spaces or expand to fill huge rooms!
1. When you blow air into a balloon, the gas spreads out to fill the rubber skin. 2. If you squeeze the balloon, the gas particles move closer together. 3. If the balloon pops, the gas particles immediately fly out to fill the entire room!
Which state of matter has a fixed shape that does not change?
What do the particles in a liquid do?
A gas will expand to fill up any container it is put into.
Review Tomorrow
In 24 hours, look around your kitchen and try to find one example of a solid, a liquid, and a gas.
Practice Activity
Try this on your own: Fill a glove with water and freeze it. Watch how it changes from a liquid (taking the shape of the glove) to a solid (keeping the hand shape even when the glove is removed)!