Elementary students are often limited in the ability to perform good science projects and often there are misunderstandings about what a science project is. Some teachers allow students to make models or posters, but true scientific investigation goes to the heart of science.
Cooling by Evaporation and Conduction
Heat energy is transferred from one place to another by various processes. This experiment investigates heat transfer by conduction and evaporation. The experiment requires simple materials and is easy to set up. Allow about an hour for the experiment. Completion of a poster will take longer.
Materials Needed for Experiment
- 1 pocket thermometer (these have a stem with a dial on top of the stem so they can be immersed in a fluid);
- 2 Paper or Styrofoam cups — 8 ounce capacity;
- 1 thin plastic, non-insulated cup — 8 ounce capacity;
- 1 cardboard square big enough to cover the top of one Styrofoam cup — approximate 4" X 4";
- poster for display — three panel poster is preferred.
Procedure
Safety note: Hot water is used from the tap. Parental supervision is advised to ensure careful handling of the water.
- Adjust tap water temperature to 120 to 125 degrees F.
- Carefully fill each cup to within one-half inch of the top.
- Place three cups side by side on a kitchen counter.
- Check temperature of each cup — they should be very close to the same temperature — record each temperature.
- Cover one Styrofoam cup with the cardboard square.
- Wait 30 minutes. Do not disturb the cups. Do not handle them or remove the cardboard square during this time.
- After 30 minutes has passed, record temperatures of water in all three containers.
Discussion of Science Fair Project
The results should indicate that water in the cup with the lid is the warmest. The thin-sided, non-insulated cup should be coolest. The cup with the lid lost the least heat by evaporation because the lid kept hot, fast water molecules inside. It lost heat slowly through the Styrofoam by conduction — Styrofoam is a poor conductor of heat.
The remaining Styrofoam cup — without the lid — lost heat rapidly by evaporation, but slowly by conduction. The thin-sided, non-insulated cup lost heat rapidly through its thin sides and by evaporation.
This experiment demonstrates why hot beverages are kept in insulated containers with lids. Also, it shows that the best way to cool a liquid that is too hot is too make sure it is not covered. This is why people blow on something that is too hot — it helps remove the molecules with the highest amount of heat energy — i.e., it hastens evaporation.
Displaying the Results of the Science Project
The display should have a title for the experiment. The arrangement of various steps in the scientific method will depend on grade level and instructions from the teacher. A review of the scientific method is a good idea.
For elementary students it is usually sufficient to state a hypothesis, describe the procedure, state a conclusion, and communicate results using the display poster. A bar graph should show the recorded temperature changes for each cup if the student has been introduced to bar graphs.
Otherwise three cups can be drawn, cut out, and pasted on the poster — the cups should have the temperature changes written on them. Neatness usually is part of a scoring rubric for a science project. The graph or drawing should be in the center panel.
A few photographs of the experiment help people understand what was done. These can be displayed on the right side of the panel.
Heat energy great for science projects because there are so many relevant ways to investigate it. This project is easy for a child to do and understand. The principles involved help prepare younger students for standards they will learn in later science courses.
Source:
- “Welcome to Science Fair Project World!” (Accessed October 24, 2011).
Harvey Craft - I am a retired educator with diverse experience. I read anything science, education, and history. I write to share what I learn.
