Gas Matters

Kids love this dynamic demonstration. Easy and effective!

MATERIALS

Baby food jar
Carbonated water (or clear carbonated soda)
1 tsp table salt

PROCEDURE

1. Fill baby food jar ½ full with carbonated clear liquid.
2. Ask, “Do you think carbon dioxide gas is considered ‘matter’?” “How do you define ‘matter’?” (Has mass and takes up space.)
3. Ask, “What do you think will happen if we add some salt to this jar?”
4. Add 1 teaspoon of table salt to the jar. Observe. Ask, “Why do you think this happened?”

EXPLANATION

The bubbles in the carbonated liquid are full of carbon dioxide. Carbon dioxide gas takes up space. When you add the salt molecules, the salt molecules push the carbon dioxide molecules out of the way. When the carbon dioxide bubbles rise to the top, they bring small amounts of soda with them. Replacing a gas with another substance is called “effervescence.” Gas is considered ‘matter’ because it fulfills the two requirements: it takes up space, and, it has mass (weight).