The Science of Gases
During the conduct of this activity, students observed the following properties.
- Gases take up space. Gases are one of the three basic states of matter (the other two are liquids and solids). Gases take up space, but unlike liquids or solids, they have no definite shape or volume unless they are placed into a container. In this activity, students observed that gases take up space (they saw the balloon inflate). The molecules in gases freely move randomly and are more or less evenly distributed. Changes in temperature and pressure can change the volume, or how much space, gases fill. For example, an increase in temperature will cause gases to expand and rise. However, an increase in pressure will cause gases to contract.
- We cannot see or smell many kinds of gases. For example, the air we breathe is made of a mixture of gases that we cannot see or smell. At the same time, some gases have odors.
- Gas can be produced by mixing two compounds. Vinegar is a weak acid (acetic acid) and baking soda also is known as sodium bicarbonate. In this activity, vinegar and baking soda were mixed together to produce a chemical reaction that released carbon dioxide. The carbon dioxide filled up the plastic bottle and inflated the balloon. Explain to students that living organisms, including humans, also release carbon dioxide, which is released from our bodies when we breathe out. The carbon dioxide produced in our bodies also comes from chemical reactions.
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Funded by the following grant(s)
The Environment as a Context for Opportunities in Schools
Grant Numbers: 5R25ES010698, R25ES06932
Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education