• Clear containers - 4
• Baking powder
• Baking soda
• Measuring spoons – 5 mL, 15 mL
• Vinegar
• Water

1. Place 15 mL of baking soda in each of two clear containers.
2. Add 30 mL water to one container and 30 mL vinegar to the other container. Write down your observations.
3. Using clean spoons , place 5 mL baking powder in each of two, clean, containers.
4. Add 30 mL water to one container and 30 mL vinegar to the other container. Write down your observations.

• Look at the ingredients on a commercial package of baking powder. Based on your observations what does baking powder contain?

• Why do you think it is necessary to add substances that produce a gas during baking?

To produce light, fluffy cakes and breads. a gas must be released during the cooking process. This gas is usually carbon dioxide, which is produced by both baking powder and baking soda; however, this simple experiment demonstrates that the two leavening agents do not act in the same way.

Baking soda contains only sodium bicarbonate and an acid must be added to release carbon dioxide gas. In this experiment, vinegar is the acid, but in baking, cream of tartar or buttermilk could also be used as a source of acid.

Unlike baking soda, baking powder will release carbon dioxide gas just on the addition of water. The ingredients on a package of the commercial product will show that baking powder is a mixture of baking soda (sodium bicarbonate) and one or more other chemicals. These chemicals are dry acids that are activated by the addition of water.