Summary Feel how a layer of fur can stop your hands from getting cold. Science content Biology: Features, Adaptations of Living Things (K, 1, 3, 7) Lessons activity is in Bears and hibernation Fur and Feathers Materials pieces of cloth of varying thickness, including very thin and furry ice cubes small baggies, to double-bag ice cubes in optional: bear fur, or other skin of furry animal Procedure Hold the bag of ice cubes, to feel how cold they are. Then wrap them in each cloth in turn, and feel whether the cloth can keep your hand warmer. (Note that if your hands get very cold from the ice, it will be hard to tell what the cloth does, so encourage students to use each hand in turn to give them time to adjust between each test.) Students should find that the thicker, more furry, cloths keeps their hand warmer. The air trapped in the thicker fibres insulates from the cold (i.e. it prevents heat from moving away from your hand). Animal fur and feathers trap air to keep animals warm, sometimes from extreme cold. Local animals with thick fur include bears, otters. If available students can feel real animal fur. They can dig one hand into the bear fur and keep the other hand out of the fur, to compare, and feel how the hand in the fur becomes warmer (as the heat from the hand can't escape with the fur insulation surrounding it). More information on animal fur: Fur also keeps out other kinds of weather besides cold. (Wind and rain). Dig one hand into the fur and blow over it. Feel how protected from the wind it is. Dig one hand into the fur, and one not. Can you feel the drops of water in each case? Bear fur is made of two types: find the downy underfur, and the coarse guard hairs. Underfur is soft and dense and is the insulator. The outer guard hairs are thicker, longer and coarser. They do insulate, but have other purposed as well: They keep out dirt, debris and insects. They repel water (bears shake just like a dog when they come out of water). They can be used to communicate. Raised hackles indicate that the bear is angry or frightened. Bears molt annually in the early summer. They shed both their underfur and outer guard hairs, leaving only a short, sleek summer undercoat. Their new coat is growing in as the old one is being shed, so that by fall they have their thick, luxurious coats once again.www.americanbear.org Grades taught Gr K Gr 1 Gr 2
