Blubber hand
Fat hands are better than frozen hands. Try your hand at this icy experience.
What you need
- large mixing bowl (or similar container)
- cold water
- ice
- 2 zip-lock bags
- soft margarine or lard
- spoon
What to do
- Fill the bowl with water and ice to make icy-cold water.
- Use the spoon to fill one of the zip-lock bags with soft margarine or lard.
- Cover your left hand with the empty zip-lock bag.
- Put your right hand in the first zip-lock bag, covering your hand with the margarine or lard.
- Place both hands in the icy water, being careful to keep the openings of the zip-lock bags above the water to prevent water from entering the bags.
- Keep your hands in the water for about 1 minute or until your hands feel uncomfortable.
- Which hand feels colder?
- Remove your hands from the icy cold water, take off the bags and wash your hands.
- If this is done as a classroom activity, keep a tally of the number of students who felt their left hand was colder, felt their right hand was colder or couldn’t tell the difference. Discuss the class’ results.
What's going on?
Did you know?
When southern humpback whales are first born they don’t have enough blubber to survive in cold Antarctic waters. Adult southern humpback whales migrate from Antarctica to the north-eastern coast of Australia to give birth to their calves in warmer water. The calves feed on their mother’s milk, grow quickly and develop a layer of blubber. Once the calves have enough blubber, they migrate south to their cold, Antarctic feeding grounds. Learn more...
In most cases, the left hand should feel colder than the right hand. Heat transfers from warmer objects to cooler objects. A human’s body temperature is 37°C and the temperature of the icy water is close to 0°C. The heat from the left hand transfers into the cold water. An insulator slows down the transfer of heat. The right hand feels warmer because the margarine or lard acts as an insulator to slow down the transfer of heat from the right hand to the cold water.
In this activity, the zip-lock bag represents the skin of a whale and the margarine or lard represents the blubber of a whale. Whales are mammals and all mammals are endothermic which means they produce body heat through metabolism. Whales maintain their body temperature at close to 37°C by controlling their rate of metabolic heat production.
Whales live in a marine environment which is colder than their body temperature. Amazingly, some whales live part of the year in the near-freezing Arctic or Antarctic waters. Whales are capable of surviving in cold ocean waters because they have many adaptations that help to reduce heat loss to keep their bodies warm. For example, they have a thick layer of fat, called blubber, just beneath their skin. The blubber acts as an insulator to slow down the transfer of heat from their warm bodies to the cold ocean water.
Investigate
Try other materials (Eg. cotton wool, tissues, vegetable oil, etc.) in zip-lock bags to determine if they are better or worse insulators than margarine or lard.
