3.7 based on 3 ratings

Updated on Feb 06, 2012

Grade Level: 7th - 9th; Type: Physics

Objective:

This science project determines whether a hot liquid cools off faster when liquid is added before or after a two minute wait.

• Which material is the best insulator?
• Which material creates the most static electricity?

Ah…a nice, hot cup of coffee. Until you add creamer, that is. If you know that you won’t be drinking your coffee for a couple of minutes, is it smarter to add your creamer right away, or to wait until right before you drink it? Knowing the answer to this question can mean the difference between a steaming drink and a lukewarm one.

Materials:

• Pitcher
• Water
• Refrigerator
• Kettle
• Stove
• Mug or foam cup
• Thermometer
• Stopwatch or watch with second hand
1. Put a pitcher of water into the refrigerator and a kettle of water on the stove. When the pitcher of water is completely cooled, boil the water in the kettle. The cold water will represent the creamer, and the warm water will represent the coffee.

2. Pour ½ cup of the boiled water into a mug or foam cup. Measure the temperature of the boiled water by placing a thermometer into the cup and stirring it around.

3. Pour ½ cup of cold water into the boiled water right after measuring its temperature.

4. Wait exactly two minutes.

5. Measure the temperature of the mixture. Record both measurements in a chart, such as the one below.

 Method Temperature Change Average Temperature Change Method 1 1. 2. 3. 4. 5. Method 2 1. 2. 3. 4. 5.

1. Reboil the water, and place the pitcher back in the refrigerator for a few minutes.

2. Repeat Steps 2-4 four more times, and record all data.

3. Pour ½ cup of the boiled water into a mug or foam cup. Measure the temperature of the boiled water by placing a thermometer into the cup and stirring it around.

4. Wait exactly two minutes.

5. Pour ½ cup of cold water into the boiled water.

6. Measure the temperature of the mixture. Record both measurements.

7. Reboil the water, and place the pitcher back in the refrigerator for a few minutes.

8. Repeat Steps 2-4 four more times, and record all data.

9. Analyze your data. Which method cooled off the boiled water the most? Why do you think that happened?

Terms/Concepts: Static electricity; Conductors and insulators; What are some examples of good insulating materials?

References:

First Place Science Fair Projects for Inquisitive Kids, by Elizabeth Snoke Harris. Pp. 66-67.

Keren Perles has worked as an educational writer, editor, teacher, and tutor of all ages. Her experience spans the subject areas, from science and math, to English and the Hebrew language.