Insulation

Objective:

The objective of this lab is to learn about Insulation and how it affects heat transfer between materials

Background on

Ever wondered why the inside of your house is warm and cozy when the outside may be covered in freezing snow? Or have you ever wondered why the house can feel so cool but when you step outside you feel like you are completely and utterly melting? The answer is that there is a temperature difference between the two areas due to the materials in the wall transferring heat very slowly from one side to the other. This material is commonly known as insulation.

Insulation helps to maintain the temperature in one area when the temperature outside of that area is very different. Animals utilize insulation in their bodies to help keep them warm during the winter or in cold waters. The insulation of animals is made up of fat. Fat is very slow to transfer heat from one side to another. The thicker the layer of fat the more heat that is retained inside the animal. For animals that live in freezing water this can be the difference between life and death. If for instance a seal is unable to build up enough fat stores in its body before the winter and then maintain those fat stores the seal will be unable to keep itself warm in the barely above freezing water that it lives in.

Materials

• 4 – 2-gallon buckets (smaller buckets are fine, just need buckets large enough to fit the kids hands in their insulated bags)
• Water (hot, room temperature, iced and dry iced)
• 2 Quart-sized Ziplocs
• Vegetable shortening

Method

Prepare Experiment

• Pass out all materials and make sure they are well organized in front of the kids

Run Experiment

1. Fill one bucket 2/3 of the way with room temperature water
2. Fill two buckets ½ of the way up with cold water
3. To one of the cold water buckets add enough ice to have it filled 2/3 of the way up
4. To the other cold water bucket add enough dry ice to have it filled 2/3 of the way up
5. Allow these buckets to sit and cool or acclimate to room temperature depending on the bucket while you make the next part of the lab.
6. Take the Ziploc bags
7. Open one bag and put close to two cups of vegetable shortening into the bag along one of the sides
8. Take the second bag and flip it inside out
9. Stick the second bag into the first bag making sure to line up the opposite sides of the Ziploc (same to same will not close opposite to opposite will seal)
10. Zip together the different parts along the side of the first bag the has the vegetable shortening
11. To the area between the other side of the bag containing the shortening and the second bag add another 2 cups of vegetable shortening
12. Zip together the different parts along the side of the first bag the has the vegetable shortening
13. Gently spread the vegetable shortening throughout the cavity created between the two bags so that it is evenly distributed
14. Boil enough water to fill your last bucket up 1/3 of the way
15. Add boiling water to the bucket
16. Add enough room temperature water to fill the bucket 2/3 of the way and set aside (you could fully use boiling water but need to be very careful that the kids do not burn themselves)
17. Stick your hand into the inside of the inner Ziploc bag of your shortening bag glove
18. Stick your hand into the dry ice bucket for 5-10 seconds
19. Now use your other hand to touch the outside of the bucket for 5-10 seconds
20. Do you notice a difference in how your hands feel?
21. Switch which hand is in the shortening glove
22. Now place your shortening hand into the ice bucket for 5-10 seconds
23. Now use your other hand to touch the outside of the bucket for 5-10 seconds
24. Do you notice a difference in how your hands feel?
25. Switch which hand is in the shortening glove
26. Now place your shortening hand into the room temperature bucket for 5-10 seconds
27. Now use your other hand to touch the outside of the bucket for 5-10 seconds
28. Do you notice a difference in how your hands feel?
29. Switch which hand is in the shortening glove
30. Now place your shortening hand into the boiling water bucket for 5-10 seconds
31. Now use your other hand to touch the outside of the bucket for 5-10 seconds
32. Do you notice a difference in how your hands feel?

Analyze Data

The vegetable shortening of the glove acts as a layer of insulation protecting the kids hands from both hot and cold. The hotter or the colder the material that the glove is stuck in the more the kids will feel the temperature change.

Conclusions

Insulation helps to limit the heat exchange between different materials. From the cold on the outside of the house to the warmth on the inside of the house, without insulation more heat would be transferred leaving us to constantly have to heat our homes when it is cold outside in order to stay warm which would not only be expensive it would be very wasteful. The same thing can be said for us, by using jackets that are insulated against the cold we are able to keep more of our body heat against our bodies instead of losing it to the environment, allowing us to stay warm in the cold and enjoy all the amazing things the winter has to offer.

Make It Your Own

Fat is an amazing insulator, as we have seen in this lab and as we know from whales and seals storing fat to stay warm in arctic and Antarctic waters. Knowing how great fat is an insulator can you think of other things to try to insulate your hands? What about using cotton in the glove? What if you tried a liquid fat instead of a solid fat? What if you used a fully reflective material such as that material used for a thermal bivvy?

Extension Activities to do at home

Using simple ice water and snow gloves try to test the insulation of the glove by putting it in a Ziploc bag (so it does not get wet) then place it into the ice water for 10 minutes, pull the glove out and put it on. Is the inside of the glove still warm? Try with another glove of a different size or thickness?