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Animals have some unique adaptations to stay warm. Discover what conduction of heat and insulation have to do with staying warm!
What You Need
● Containers (big enough to fit a hand inside)
● Ice water (or snow, if available)
● Plastic bags (sandwich bags) or wrap
● Wrapping materials - fake fur, cotton balls, polar fleece, wool sock, etc.
● Lard (or shortening, like Crisco)
● Balloons
● Straws
● Paper Towels
What to Do
- Fill a container with ice water or snow. Make sure there is enough water or snow to cover an entire finger - preferably a whole hand.
- Using your choice of materials, wrap each finger with a different material, cover it with plastic (cello wrap or sandwich bag), dip it in ice water/snow and see which material keeps your finger warmest. The wrapping materials may include fake fur, cotton balls, foil, polar fleece, a wool sock, or any other materials you would like to test as insulation. Which materials were the best at keeping your finger warm?
- To test the insulating properties of air, place a balloon on one finger without air in it. Then, insert the straw into the balloon (keep it on your finger) and blow some air into it. Test. Does the layer of air help keep your finger warmer? Can you think of any animals that have a layer of air around their body?
- To test the insulating properties of lard, put your hand into one inside-out plastic sandwich bag and scoop a small handful of lard, using the bag to keep your hands clean. Place the lard and plastic bag inside another plastic sandwich bag. If you turned the first bag inside out, you should be able to seal the two bags together, keeping the lard from coming out. Spread the lard around between the two bags, making a sort of “lard mitten”. Place your hand inside the “lard mitten” and test for insulation. What animals have a lot of fat on their body? What is the purpose of this fat (or blubber)?
What’s happening?
Insulator is another name for a material that is a poor conductor of heat. Insulators slow down the transfer of heat from an object or place that is warm (like your hand) to an object or place that is cooler. Heat always moves from hot areas to cold areas in an attempt to even out the temperature between the two places. Insulation is used to keep hot things hot and cold things cold.
Why does it matter?
Animals have a variety of different mechanisms to keep warm. Blubber (fat, like lard) and fur keep Arctic animals warm. Down feathers trap a layer of air next to the body to help keep birds warm.
Materials that insulate to keep heat in or cold out are very important in everyday life to keep us healthy and comfortable. A thermos will keep milk cold and fresh so that it is still safe to drink at lunchtime. Fleece-lined slippers keep our toes cozy and warm when the floors are cool in winter. Maintaining appropriate temperatures in buildings is important and the energy to provide heat can be expensive. Heating and cooling buildings is one of the greatest uses of energy worldwide. In order to reduce energy consumption, proper insulation is necessary to cut heating/cooling costs, while maintaining comfortable temperatures. Although covering a building in blubber would not be an effective way to insulate a building, trapping air in material, like birds do with their feathers, is a commonly-used strategy. Fibreglass, a material made from very fine fibres of glass, traps air in its fibres and is used to insulate buildings and homes.
Investigate further
● To complete this exploration with more precision, instead of using your finger, try filling a small water bottle with room-temperature water and placing a thermometer in the bottle. Pack plastic bags with insulating materials and place the bottle in the bags. Record the temperature of the bottle before placing it into the ice water/snow. Measure temperature changes every 5 minutes for 25-30 minutes. Repeat with different insulating materials. How do the different materials compare as insulators?
● Repeat the exploration using hot water instead of cold water. Be careful that you don’t use water that’s too hot. You don’t want to burn yourself. Are the same insulating materials still the best when hot water is used?
● Find examples around your home of insulators we use every day to keep hot things hot and cold things cold. Possible items: thermos, tea cozy for a teapot, insulated lunch bags and picnic totes, down-filled winter coats, fur-lined boots or gloves, foam tubes around hot water pipes, Styrofoam lining in the toilet tank, spray foam insulation on walls, etc.
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