1. (15 Minutes) Watch the video Part(icles) of Your World: Crash Course Kids to introduce the concept of particles, phase changes, and thermal energy.
Ask the students the following questions:
Is the speed of water molecules different in hot and cold water?
Can we design a test to find out?
(One way of accessing prior knowledge at this point would be to ask students if they have ever watched or helped make iced tea. Ask what was done to the water before the tea bags were added.)
2. (20 Minutes) Explain the students will be using food coloring to test particle motion in water with different temperatures. Have the materials listed on the board so that the students will know what is available. Ask the students to help design an experiment to test the effects of temperature on particle motion. Guide the students by asking questions like: Should we use the same amount of water in each cup? Should we use the same size cups? Should we use the same amount of food coloring? Should we put the food coloring in at the same time? Allow the students to come up with a plan for testing the effects of temperature on particle motion. Have them write down their plan in science notebook before going to the next step.
3. (10 Minutes) Allow the students to get the materials needed for conducting the experiment in their groups (The teacher will need hot and cold water available for students. If boiling hot water is used, please stress safety).
4. (15 Minutes) Have students conduct the experiment as planned out in their groups. Remind the students to record the temperature of the hot and cold water prior to adding food coloring. Once they have recorded the temperatures, instruct them to add the food coloring at the same time and observe what happens. Note when changes occur. Note the time when they think the food coloring has sufficiently mixed.
5. (10 Minutes) Have students explain how temperature affected the motion of the particles and the speed at which the food coloring mixed with the water. Look back at your prediction from step one and explain why you were correct or how you would change your prediction. Summarize what you learned during this lesson.