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Exploring the air around us and learning that gases are matter even if we cannot see them.
Imagine you are a fish swimming in a giant ocean of water. Did you know that right now, you are 'swimming' in a giant ocean of air?
Even though your bedroom might look empty, it is actually full! Everything in our world is made of matter. Matter is anything that takes up space. Air is a special kind of matter called a gas. Most gases are invisible, which means we cannot see them with our eyes. Even though we can't see air, it is tucked into every corner of the room, inside your lungs, and even inside an 'empty' cup!
Quick Check
If you have a box with no toys in it, is it truly empty?
Answer
No, it is full of air (a gas)!
Gases are like explorers! Unlike a solid rock that stays in one shape, a gas will expand. This means it spreads out to fill up every bit of space it can find. If you put a little bit of gas into a big jar, it won't just sit at the bottom. It will zoom around until it fills the entire jar from top to bottom. We can think of the volume of gas as being equal to the volume of its container .
1. Take a flat, rubber balloon. 2. Blow air from your lungs into the balloon. 3. Watch as the invisible gas pushes the walls of the balloon outward to make room for itself.
Quick Check
What does it mean when a gas 'expands'?
Answer
It means the gas spreads out to fill the whole space it is in.
We might not see gas, but we can definitely feel it! When air moves quickly, we call it wind. You can feel the wind pushing against your skin on a breezy day. We can also see how gas affects other things. When you see a flag waving or a kite flying, you are seeing the invisible gas pushing against those objects. It takes up space and has power!
1. Imagine someone bakes chocolate chip cookies in the kitchen. 2. The smell is actually tiny bits of gas. 3. Because gas expands, those 'smelly' particles travel from the kitchen all the way to your nose in the living room!
If you weigh a flat balloon and then weigh a balloon full of air, the full one is slightly heavier! 1. Empty balloon weight = 2. Full balloon weight = 3. Since , we know the gas inside has mass and is real matter.
What is air?
What happens to a gas when you put it in a bottle?
Even though we cannot see air, we can feel it when the wind blows.
Review Tomorrow
Tomorrow, try to explain to a friend why an 'empty' glass isn't actually empty.
Practice Activity
Next time you are outside, look for three things that prove invisible air is there (like moving leaves or a flying bird).