Materials:Luna, Projector, 16-ounce cup, 1/2 cup vinegar, 2 Tablespoons bakinsoda, raisins, tap water
Fill the cup with tap water. Place the Luna in front of the cup and connect it to the computer and projector. Discuss density with the students and explain how raisins have a greater density than the water.
Ask the students to predict if raisins will float or sink in the water. While recording the process with Luna, place the raisins in the water and observe what happens. [The raisins will sink.] Discuss this with students and empty the cup.
Explain how mixing vinegar, water, and baking soda creates a chemical reaction that produces carbon dioxide gas. our vinegar into the cup, fill to the top with water, then stir in the baking soda. Capture the process with Luna so students can see how the carbon dioxide is created.
Discuss what is happening in the glass. As students discuss the bubbles rising ask them to predict what will happen when the raisins are placed in the solution.
Place the raisins in the cup and capture what is happening with the raisins.
[First the raisins will sink, then carbon dioxide bubbles will adhere to the raisins and cause the raisins to float. At the surface the bubbles release and the raisins sink.]
Have the students form conclusions about the chemical reaction, the bubbles, and how the raisins behave as a result of this chemical reaction.
Have the students repeat the process on their own, using Luna to record it. Have them write a short paragraph using observations and science vocabulary.
Have the students identify other objects to place in the solution and make predictions about how they will respond to the carbon dioxide bubbles.