Matter and its properties (grade 5) · lesson

Particles too small to see

💡 Matter is made of particles too small to see, so it can still be there even when you can't see it.

Matter is anything that takes up space and has weight. Air is matter. You can't see it, but it fills up a balloon.

All matter is made of tiny particles. They are far too small to see.

When sugar dissolves in water, it breaks into particles too small to see. The water still tastes sweet, so the sugar is still there.

When water boils, its particles spread far apart and become a gas called water vapor.

🧠 How to think about it

If you can't see something, look for another clue. Sweet taste shows the sugar. A growing balloon shows the air.

💡 When matter melts, dissolves, mixes, or changes shape, the total weight stays the same if nothing gets in or out.

When matter changes, the particles do not vanish. They just move around.

So ice that melts weighs the same as the water it becomes. A clay ball rolled into a snake weighs the same.

If you dissolve 10 grams of salt in 100 grams of water, you have 110 grams. Add up the weights.

This is true even when a gas forms, as long as the container is sealed. The gas is still matter, and it has weight.

🧠 Let's work it out

What do you think comes next?

💡 When two things mix and make something with new properties, like gas or solid bits, a new substance has formed.

Some changes only change shape or state. Cut paper is still paper. Melted ice is still water.

Other changes make a new substance. Baking soda and vinegar make bubbles of gas. Burning wood makes ash and smoke.

Signs of a new substance include bubbles, a new color, cloudiness, or new solid bits.

🧠 Let's work it out

What do you think comes next?

💡 We can tell materials apart by their properties, like what a magnet pulls or what carries electricity.

A property is something you can observe or measure about a material.

Iron is pulled by a magnet. Sand is not. So you can use a magnet to pull iron out of sand.

Metals like copper and aluminum carry electricity well. Wood and rubber do not.

Weight is a property too. We measure it with a scale, in grams.

🧠 How to think about it

To separate two things, find a property one has and the other does not. Then use it.