Fun for Kids

EXPERIMENT #1: Which Insulation Keeps Water Hot or Cold the Longest?

Before doing any testing make sure your parents know what you are doing and ask for their help.  Be especially careful if you are using warm water from the sink and don’t heat anything on the stove or microwave without your parent’s help.

Suggestion: Read all the way through the directions first. Then do a practice run. Once you figure out how to do the experiment, you can try lots of different materials to see how effective they are at slowing heat movement.

1. Decide on some materials you want to test for their insulating ability. 

Keep in mind that all materials have some insulation value or ability to slow heat flow, and that materials that keep air from moving are typically better insulators. Many materials found around your home can be used for the test.  For example, you can use:

• Cotton towels
• Torn up paper
• Dirt
• Leaves

2. After you've decided on and collected your test materials, you will need the following:

• A thermometer (best to find an unbreakable type)
• A small paper or plastic cup with sealable lid (take-out drink cup, or yogurt container work)
• A box with lid. The box needs to be just large enough to hold your cup and at least an inch or two of insulation material. (A shoe box would work)
• Something to write with and a clock or watch to keep track of time with
• Note paper for recording time and temperatures
• Graph paper for plotting your result

3. Poke a hole in the center of the box lid and the center of the cup lid.

The size of the hole will depend on your thermometer. You will need to be able to insert the thermometer through both the box and cup lids and down inside the cup to measure the temperature of some water you will put in later.

4. Put some test insulation material into the bottom of your box. Then put the cup in near the middle of the box. Surround the sides of the cup with the same type of insulating material you've got on the bottom.

Try to get the same amount of insulation on opposing sides of the cup so it is as even as possible. This is because the heat will flow more rapidly where the insulation is thinnest.

5. Put some warm water from the sink or cold water from the refrigerator into pitcher. 

Be careful if you use warm water from the sink because it might be hot enough to burn you.

6. Fill up the cup to just below the top with water.

Put the lid on the cup, and then fill the rest of your box (covering the cup lid) with the same insulating material that is on the sides and bottom. Do your best not drop insulating material into or completely cover up the hole you made for the thermometer.

Insert the thermometer through the lid for a box. Then cover the box with its lid so that the thermometer is inserted into the lid of the cup and down into the water.

7. Read the temperature on the thermometer every 15 or 30 minutes depending on how fast the temperature changes.  Write down the temperature and the time on your note paper.

Continue the temperature readings until it stops changing. This will be when the room temperature equals the water temperature which is when the heat stops moving.

8. Graph the temperature versus time elapsed for your insulation material.

9. Repeat steps 4 through 8 for each of the materials you want to test.

You don't have to start with exactly the same temperature water each time (although it might be easier to interpret your results if you always use either warm or cold water). You'll be able to tell how slowly or quickly heat moves by the slope of the line on your graph for each material. The steeper the line, the less insulation value that test material has.