Science and Technology K–6 · Year 5

Blubber glove: how a fat layer keeps a seal warm in cold water

Science understanding: Biological sciences

PracticalLow risk

The idea

A structural feature, a thick fat layer, slows heat loss and lets an animal survive in cold water, and the effect can be measured as the temperature a thermometer holds inside a fat-lined glove.

Safety card

Low riskAn adult supervises

Hazards

cold-water pain and numbness
slippery fat

Controls

hand test capped at 30 seconds and voluntary
adult supervises the iced water
paper towels for fat

Note

Risk assessment before the lesson using Primary RiskAssess or the school's own template.

What you need

4 zip bags about 18 cm by 20 cm (2 pairs)
250 g vegetable shortening or lard
a bowl of iced water at 2 to 5 degrees Celsius
2 digital thermometers
duct tape
timer

How to do it

Make the blubber glove: spread the shortening inside one bag, put a second bag inside it and tape the rims together so a hand or a thermometer sits in the inner bag surrounded by fat.
Make the control glove the same way with no shortening, pressing the air out from between the two bags before taping (a trapped air layer would insulate too).
Put a thermometer into each glove and lower both into the iced water to the same depth. Read both every 30 seconds for 5 minutes.
Graph the two temperature lines.
With adult permission, a learner puts one hand in each glove in the iced water and reports which stays comfortable, withdrawing as soon as either hand feels painful, at most 30 seconds.
Measure the thickness of the fat layer and relate the result to seals, whales and penguins.

What you should see

The thermometer in the control glove falls quickly toward the water temperature; the thermometer in the blubber glove falls more slowly and stays warmer through the 5 minutes. Fat has a thermal conductivity of about 0.2 W per metre kelvin, about a third that of water. 250 g of shortening (about 280 cubic centimetres) spread between bags about 18 cm by 20 cm makes a layer about 4 mm thick over both faces, or about 8 mm if it is spread over one face only, and that layer between the cold water and the inner bag lengthens the time to cool, so the two graph lines separate and stay apart.

What changes

What you change: fat layer present or absent
What you measure: temperature inside the glove over 5 minutes
What you keep the same: water temperature
depth
bag type
starting temperature

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

Fat makes heat.
Seals are warm because the sea is warm.
Fur works the same way as blubber in water (wet fur loses most of its insulation; blubber does not).

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science and Technology K-6 Syllabus (2017), current, taught until 2026; code read from the syllabus document on 22 September 2026ST3-4LW-S ST3-1WS-S
Science and Technology K-6 Syllabus (2024), implemented from 2027; NESA's timeline is 2026 plan and prepare and 2027 start teaching, and schools may choose to implement it during 2026; Stage 3 content: 'Observe behavioural and structural adaptations of plants and animals, and suggest how these may help them survive in their environments', which sits in the focus area whose knowledge outcome is this one; code read from the outcomes page and the content read from the Stage 3 content page on 23 September 2026ST3-SCI-01
Science and Technology K-6 Syllabus (2024), implemented from 2027; NESA's timeline is 2026 plan and prepare and 2027 start teaching, and schools may choose to implement it during 2026; code read from the outcomes page on 22 September 2026ST3-PQU-01
Australian Curriculum v9AC9S5U01AC9S5I02AC9S5I03AC9S5I05

Sources

The pages the author read to write this activity.

All Concept Studio activities