Testing Insulation

Students will be exposed to a cold environment. Limiting the exposure is the key for safety. Possible ways to do this is by limiting the number of thermometers that each student has to read. Pre-teaching thermometer reading can also shorten the time spent outside.

The water all ends up cold so have a plan to ensure that students will not have it spilled/poured on them. Glass thermometers are fragile so observe students when they are engaging with them.

Insulation should be created to surround your water container on all sides except for the top. The material can range from testing various snow mittens to building insulations (fiberglass, polystyrene, cellulose, spray foam) to traditional clothing materials (wool, fox fur, beaver fur, sod). This step will vary depending on what materials you use.

Depending on the grade levels, the insulation can be selected and designed in advance, students can design with pre-selected insulation materials, or students can select the materials and design with them.

Tests can be done with different materials or with different thicknesses of materials.

Containers should be filled with water to the same level. Water should be allowed to sit at room temperature until all containers are at the same temperature. Containers should not have insulation on them at this stage as it can keep the water from reaching the same level. Have one container prepared that will not have insulation. This is your control.

You can also test insulation with different starting temperatures. It is more difficult to ensure that all the hot/cold water is at the same temperature though.

This can be a good time to have students record their hypotheses of what will happen.

Record the temperature values of all your water containers. Depending on the accuracy of your thermometers there may be a few degrees of variance. Depending on your thermometers you may need to discuss methods for reading them and how to round to the nearest whole degree.

You should also determine if the readings will be in Fahrenheit or in Celsius.

Place the containers into a cold environment. The ambient air temperature should be below freezing and below zero helps to speed up the process.

Record the ambient air temperature.

Record the temperature of each container every 5 minutes. Continue this process until you run out of time, all the containers have reached freezing (do not let the container build up to much ice as it may damage your thermometers), or none of the temperatures are showing change.

How you approach this step will depend on your time constraints and on the level of students you are working with. It can range from you entering the data into a spreadsheet, each student graphing a particular container, or each student graphing all the containers. Graphs can be made by hand or electronically. If you have an empty graph with units printed onto overhead paper (and have an overhead or document camera) you can have each student make one graph and then layer them up to display all the data at once.

Give students time to observe the data and the graph. Use a method to have students write or talk about their observations. Some possible questions to ask are:

• Does the data match their hypotheses? Does anything surprise them?
• Do there appear to be any errors in the data or in the graph?
• Was an error made in implementing the experiment?
• What material was the best at insulating the water? Which was the worst?
• If they had the opportunity to run the experiment again, what would they change and why?
• How does the air temperature affect the cooling process of the water? What would the lines look like if the air was colder or warmer?
• Would the data look the same if a liquid other than water was used?
• How would the data be affected if an insulated lid was also used?