4. Staying Cool (Conduction)

The purpose of this simple experiment is for students to investigate the properties of materials:

Lots of materials can be used to help insulate (slow/stop melting) ice. Some materials work better than others at slowing down the speed that ice melts.

CURRICULUM LINK

Observe the effects of heat moving from one object to another,
Describe how people use scientific knowledge in their work and everyday life to control the movement of heat from one object to another

PROBLEM

Determine the relationship between how cold/warm different materials feel and how these properties might affect a melting ice block. What material would you choose to place an ice-block on to make sure it melts most slowly?

QUESTION

How could we design an experiment to find an answer to this 'melting ice block' problem?

EXPERIMENT

If nobody can come up with a better solution, here is one experiment to try…

METHOD

Choose some materials (see example) and place the materials close together on a desktop.
Allow long enough for the temperature of each item to stabilise before starting. While waiting:
1. Ask students to write down what materials they think feel coldest and which feel warmest.
2. Ask students to write down what materials they think will make an ice-block melt quickest.
After the temperature of each item has had time to stabilise, perform your experiment, writing down your results in table(s) similar to this:

Measure the following temperatures first (without ice)

Question	Paper plate	Wood block	Aluminium dish	Plastic block	Glass dish
Which of the materials feels warmest
Which of the materials feels coldest
What is the temperature of each item

MEASUREMENT

Set up a video camera or time-lapse camera system (time must be recorded on video and/or each time-lapse camera photo - you may need to include a clock on-screen)
1. Make sure all items that you will test are clearly visible in video/camera frame
2. Start your time-lapse camera recording
Quickly place a similar sized block of ice on top of each item
1. Review your video recording

Question	Paper plate	Wood block	Aluminium dish	Plastic block	Glass dish
How long does it take to melt one ice-block

Nothing works for an extended period of time, so you should move quickly!

Discuss the results for the materials that you tested and data you entered into your table(s).

Using your results, discuss the result that you observed and what they might show about heat.

Can you use your own/other evidence to help convince the class about why materials feel warmer/cooler and make ice-blocks melt slower/faster

How could this experiment be improved if someone wanted to run a similar test?

Video: WPS 3/4S Investigate Heat Transfer (0.5min)

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