“Can anyone tell me the three states of matter?”
“Kansas, Oklahoma, and Missouri!” shouts a young boy in the small group third graders with whom I’m working. “They’re the ones that matter most!”
Solids, liquids, and gases are common concepts found in today’s state science standards for elementary children, but teachers often have difficulty finding fun, hands-on activities to teach these ideas. Teachers might have students watch an ice cube melt or boil water on the stove, but there are a variety of other activities that can be done. You can bring some of these ideas to life by conducting lab activities with a high-interest substance, such as dry ice.
Dry ice is actually frozen carbon dioxide, and, when handled properly, can provide hours of fun and learning in your classroom. You should begin by making sure all students understand the safety precautions necessary when using dry ice. This substance can easily cause injury if it comes in direct contact with bare skin, so it’s important to make sure all students are wearing leather gloves if you choose to allow them to work with dry ice directly. Once they understand how to work safely, you can give them two pieces of dry ice, of approximately the same size, and a piece of ice made from water. Students can use Venn diagrams to compare and contrast the two substances. They should quickly notice that the ice made from water melts to form a liquid, while the dry ice immediately turns to a gas. If students are not yet familiar with the terms solid, liquid, and gas, now is a great time to introduce these terms. Depending upon the age and ability of your students, you can also introduce the terms melting (changing from a solid to a liquid), sublimation (changing from a solid to a gas), and evaporation (changing from a liquid to a gas).
Allowing students to enjoy “free time” with the dry ice will enable them to make more observations about this mysterious substance. You can give them cups of water, metal items (metal will “squeal” due to sudden contraction when it touches the super-cold dry ice), some dishwashing liquid, and/or other materials. Once they have done some investigating, they can share their observations and begin conducting some guided inquiry experiments. For example, you might ask them to investigate whether dry ice sublimates faster in hot or cold water. They can design the investigation, record their data, and share their conclusions with the rest of the class. Later, they can develop their own question to investigate! For more exciting ways to teach the states of matter, try the following lesson plans.
States of Matter Lesson Plans:
In this lesson students learn about the three states of matter. They investigate how materials undergo physical changes when they change from a solid, liquid or gas. Students identify example of gases, liquids, and solids, and conduct an experiment with a balloon.
This lesson has students investigate how to change a liquid into a solid, and list questions about what they discover. Students are then given a scenario in which they have to identify the similarities and differences between solids and liquids.
In this lesson students delve into the world of Oobleck, and perform experiments with this interesting substance.