Mix and Make New for Kids: Mixtures and Chemical Changes (Grades 4 to 7 Science)

Hi, I'm Luna from DoodleBeez. When you combine two substances, sometimes you just get a mix. Other times, something brand new is made! Today we will learn how to tell the difference.

In a mixture, the substances keep their own properties. Trail mix is a mixture. You can still pick out the nuts and raisins. Salt stirred into water is a mixture too.

Mixtures can be separated. You can sort trail mix by hand. You can use a magnet to pull iron filings out of sand. If you let salt water evaporate, the salt is left behind.

In a chemical change, substances react to make a new substance with new properties. Mix baking soda and vinegar and it fizzes. The bubbles are a new gas called carbon dioxide.

Look for signs of a chemical change. Gas bubbles, a color change, a new smell, light or heat, or a solid forming in a liquid. Rusting iron, burning wood and baking a cake are all chemical changes.

Here is something amazing. Whether you make a mixture or a new substance, the total mass stays the same. Atoms are rearranged, but none are created or destroyed. This is called conservation of mass.

Now it's your turn. You stir sugar into lemonade and it dissolves. Is that a mixture or a chemical change? Pause and try. It is a mixture. The sugar is still sugar, and you can taste it.

Great job! Remember, in a mixture each substance stays the same. In a chemical change, a new substance forms. Either way, mass is conserved. Practice mixtures and new substances in the Science Lab at doodlebeez.com. See you next time!