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# Measuring Global Temperature

There’s nothing average about trying to find this mean

• Science > Science as a Human Endeavour > Year 2 > ACSHE035
• Science > Science Inquiry Skills > Year 7 > ACSIS130
• Mathematics > Measurement and Geometry > Year 4 > ACMMG084
• Mathematics > Statistics and Probability > Year 5 > ACMSP118

## You’ll need

• Classroom wall (away from air conditioning vents)
• Several thermometers (more than 20 if possible)
• Blu Tack
• Fan

## What to do

1. Imagine the wall is the world (flattened out) and your challenge is to measure the average temperature of the whole world.
2. Plan where you will place the thermometers to get a good representation of the whole wall area.
3. Use Blu Tack to attach the thermometers to the wall.
4. If needed use a ladder or stable chair to place some thermometers close to the ceiling.
5. After 10 minutes, record the temperatures from each of the thermometers.
6. Add all the temperatures and divide by the number of thermometers to get your ‘global’ average.
7. Now use a fan to cool an area of the wall (covering 1 or 2 thermometers) and after 10 minutes measure the temperature again. How does the fan affect the temperature in that area of the wall? How does the fan affect the global average temperature?

## What’s happening?

Temperature changes from day to day, season to season and year to year, but global average temperatures generally stay about the same over long periods of time.

The global average temperature is currently close to 15°C. It has risen by 0.76°C since 1850.

This may not sound like much, especially since the temperature outside your classroom can change by 10°C or more in one day. But the average temperature of the whole planet does not change like the temperature outside the classroom. In fact the global average temperature is very stable, and would not change 10°C over a day, month, year, decade or even hundreds of years.