Why insulate an ice cube?
When you get ice cubes out of the freezer, or put them into a drink, they melt into water. This is because they warm up past their melting point of 0°C – insulating ice can slow this process down.
Heat energy is lost or transferred in three ways. Conduction — objects touching each other. Convection — movement of a group of molecules, such as a warm current of air rising. Radiation — electromagnetic waves. Ice melts when you take it out of the freezer because heat from the air is transferred to the molecules in the ice causing them to gain energy and the ice to change to liquid water.
Without insulation the ice cubes melt. Can you discover the best ways to stop that from happening?
Make sure you have some ice cubes to hand — make some and put them in the freezer if you don’t. You want to have a few that are all the same size.
Find several containers to do your insulation experiment in — these could be yoghurt pots, paper cups, plastic food containers or similar.
Now collect your potential insulating materials — the idea is to try a wide range to see which work best.
- Find materials in your home like: paper, fabric, tin foil, cotton wool, bubble wrap, a small towel or sponge.
- Look for natural materials in the garden or a park: leaves, straw or hay, wood shavings, tree bark, wool, soil, clay.
Decide on a selection of materials for each of your containers — keep one container within added insulation as your ‘control’. You could start by only putting your insulating material around the outside of your containers and run the experiment once like that. Alternatively, you can start by packing your containers with your chosen insulator, as well as wrapping it around the outside.
Once your containers are ready, take your ice cubes out of the freezer and place on into each container. Close them and place them all in the same area (inside or outside, it is up to you). Make sure your containers are not touching each other. Set a timer for ten minutes.
While you wait for your experiment to be ready, make a chart. Put each of your materials down one side and timings of ten minute intervals along the top.
Check on your ice cubes after ten minutes and record how each of them is doing. Has any melting happened yet? Can you see moisture on the surface of the ice cube? Has it melted completely? Once you have made your observations, close up your containers and set your timer again.
Check every ten minutes and record your findings until all the ice cubes are melted.
Did any of your materials slow down the speed the ice cube melted at? That means that they were effective insulators. Did any speed up the melting? If so, they may be good conductors of heat.
Were there any surprises? Which material gave you the most unexpected result?
Importance of Insulation
We don’t really need to insulate ice cubes, but insulation can be very important. Heating and cooling accounts for up to 50-70 percent of the energy used in an average home. Having a well insulated home can make a huge difference to this. We all need to radically reduce our energy use in order to prevent the Climate Emergency, and understanding insulation and using it efficiently can be a huge part of this. Find out more about the importance of insulation here and check out this article about insulating against the extreme cold in Antarctica.