Expansion and Contraction Activity

Teacher Notes

• Think about transporting water around the room. Devise a way for students to get water to their work space. You may need extra containers or pitchers for this purpose.
• Students will be carrying water around the room. Expect some spills and be prepared for students to clean them up by having paper or cloth towels on hand.
• Consider whether each group will be responsible for timing observations or if you will time them for the class.
• Once the balloon is on the bottle, this is a closed system. Discuss this with the students. Their drawings should each have an equal number of particles.

Materials suggestions

Provide a set of the following materials for each group of students. Suggest having students in partners or groups of three.

• Empty bottle - 16.9-20 ounce water or soda bottles
• Container large enough for bottles to fit inside, surrounded by water. Deli containers work well.
• Balloon: 7 or 9 inch balloons work best. Have extra balloons on hand. Some will break or tear as students stretch them over bottle opening.
• Room temperature water - enough for entire class, pitchers of tap water works well.
• Cold water or ice cubes to cool room temperature water - enough for entire class. A water cooler works well for keeping water cold.
• Hot water - enough for entire class, hot liquid pots or heating plates work well for this. Do not allow water to become hot enough to burn students or melt plastic containers.
• Towels (paper or fabric) to clean up water spills
• Timer or clock

Observations Key

Hot water observations

Balloon should expand slowly. Particles are moving faster. Drawing should show expanded balloon, particles spread throughout the bottle, and some particles in the balloon.

Cold water observations

Balloon should contract and may even be pulled into the bottle. Particles have slowed down. Drawing should show balloon tightly closed or pulled into bottle, particles closer together, and little or no particles inside balloon.

Room temperature water observations

Balloon should expand and return to its original position. Particles have sped up and returned to energy level they started with. Drawing should show balloon nearly flat, particles spread out into bottle, and a few particles in the balloon.

                                Fig 1. “Expand and

     Contract Key,” a drawing by

Mary Kurvers, 2014.

Expansion and Contraction Activity

Learning Objective

• I can demonstrate the expansion and contraction of a gas.

Materials

Provide a set of the following materials for each group of students.

• Empty bottle
• Container large enough for bottles to fit inside, surrounded by water.
• Balloon
• Room temperature water
• Cold water or ice cubes to cool room temperature water
• Hot water
• Towels (paper or fabric) to clean up water spills
• Timer or clock

Directions

• Place a balloon over the top of the empty bottle. The balloon should seal the bottle. Replace torn balloons.
• Place balloon inside container.
• Fill container surrounding bottle with hot water.
• Observe balloon for two minutes and record observations.
• Dispose of hot water and quickly fill container surrounding bottle with cold water. Cold water should be ready before disposing of hot water.
• Observe balloon for two minutes and record observations.
• Dispose of cold water and quickly fill container surrounding bottle with room temperature water. Room temperature water should be ready before disposing of cold water.
• Observe balloon for two minutes and record observations.

^{[1]     [2]}

     Materials                                                  Materials Assembled

Name _______________________

Expansion and Contraction Activity

Observations

Hot water observations

Cold water observations

Room temperature water observations

Drawings

Draw the balloon on each bottle below. Draw gas particles (air) to show their movement inside the bottle.

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   Hot water                                            Cold Water                          Room Temperature Water