Fabulous Fat

Seals use a combination of fat and air to stay warm.

What can you do to stay warm when it is cold? We are not the only ones that want to stay warm.

Animals have four strategies for keeping warm.

1. Lizards and butterflies bask in the sun (external heat).
2. Some, such as the great white shark (and us humans), generate heat internally. ​
3. Others, like penguins, have trapped pockets of air in their fur or feathers that act as a buffer from the cold.
4. Finally, some are covered with a layer of natural insulation that greatly slows heat loss from the body, such as the blubber that protects seals and whales from the cold. ​

Researchers combined the latter two strategies to create an artificial blubber to create better wetsuits for diving. Why does a seal not freeze to death? ​Why are seals covered with quivering blubber? We can make a blubber glove to find out.

For this activity you will need to collect:

• Some thin plastic (sandwich) bags
• Soft margarine, room temperature
• Dish, washing bowl or bucket
• Ice cubes, spoons
• Hair elastics, or rope to put around your wrists
• Stopwatch or clock with second hand

Activity steps:

1. Use a spoon to scoop margarine (or shortening) into a plastic bag​
2. Put one hand in another plastic bag. Use your left hand if you are right-handed and your right hand if you are left-handed.​
3. Spread a thick layer of margarine over the bag. Now, put this hand in the bag that already contains margarine and ensure the margarine covers your hand. This is your 'blubber glove'.​
4. Ask a friend to secure the bags with elastics so they can't come off (not too tight!). Put 2 empty plastic bags on your other hand and secure as well​.
5. Fill the dish washing bowl (or bucket) with cold water and ice cubes.​
6. Put both hands in the ice water. Make sure water does not get into the bags.
7. Time how long you can keep each hand in the water before it becomes uncomfortable

You can also use a wool or padded glove for the hand that does not have the blubber glove on. Keep it dry with a plastic bag. Can you keep your hand in the water longer than with a bag alone? What is a better insulator, blubber or the glove made of cloth?​

Simple explanation

The margarine or shortening is a fat that insulates and keeps the heat from your hand in the bag. Animals that live in very cold environments have a thick layer of fat called 'blubber' under their skin to keep their bodies warm.​ A coat or blanket keeps your body warm by trapping the heat that your body makes. In the same way, blubber traps the heat that the animal’s body makes, and keeps the cold water from taking the heat away. In this way, the animal stays warm even when the water around is very cold.

More detailed explanation

Blubber is a specialised type of fat that is found in the skin of marine mammals, such as seals, whales, and dolphins. It serves as a critical insulator, enabling these animals to maintain a stable body temperature in cold ocean environments. Blubber provides insulation in several ways:

• Thermal conductivity: blubber is a poor conductor of heat, which means that it does not allow heat to escape easily. This property helps to trap heat inside the animal's body, preventing it from being lost to the surrounding water.
• Thickness: Blubber is typically several centimetres thick, which provides a substantial layer of insulation. The thickness of the blubber layer can vary depending on the species of animal, the environment in which it lives, and the time of year.
• Blood flow: Blood vessels in the blubber layer help to regulate the flow of heat in and out of the animal's body. In cold environments, blood vessels constrict, reducing blood flow and conserving heat. In warmer environments, blood vessels dilate, increasing blood flow and allowing heat to escape.

With these strategies, marine mammals are enable to survive in cold ocean environments.

Instead of surviving less than one hour in 10-degree Celsius (50 degree Fahrenheit) water, with a wetsuit inspired by seals, a person could survive two to three hours in this temperature. This is useful for people who carry out maintenance work in cold water, or for divers who need to rescue people.

Most wetsuits are made from neoprene, a synthetic rubber that resembles a dense foam with lots of little air pockets. These air pockets help slow the transfer of heat from your body into the colder water surrounding you. The researchers replaced the air in the neoprene holes with a heavy inert gas (xenon or krypton), making it denser so that it transfers far less heat than air does.

Some STEAM opportunities include:

• Understanding of materials by exploring and comparing their properties.
• Asking questions and making observations.
• Carrying out simple tests.
• Making predictions.
• Apply learning to real world problems.

Not exactly blubber, but many other animals use fat, especially brown fat for insulation.

Ground squirrels and bats for instance, can warm up within hours after hibernation, because of their brown fat (find out more).

The brown fat of bats inspired Dutch researcher Arno Vlooswijk to create the piggy bodywarmer, saving many piglets’ lifes in their first hours (find out more).