Teacher instructions

Work through this resource material in the following sequence:

20 minutes

Tune in: What will change?

20 minutes

Find out: Experiment time!

20 minutes

Reflection: What did we learn?

Tune in: What will change?

Step 1. Discuss:

what are clouds made from?
do you think it is hot or cold in the clouds?
what makes it rain?

Step 2.

Explain the experiment to your students. Explain that you are going to test your theories on what makes it rain.

Step 3.

Students write their predictions in the first section of the Student Worksheet.

Find out: Experiment time!

Step 1.

Make sure students observe you filling the saucepan with water.

Step 2.

Set the water to boil. As it does so, explain to students that when liquid water gets really hot (above 100 degrees Celsius), it changes state, turning into steam or water vapour, which is a gas. Make sure that students understand that the steam they can see rising from the saucepan is still droplets of water, just in a different form.

Step 3.

Using oven mitts, hold a tray of ice above the steam.

Step 4.

Make sure students observe very carefully! Drops will begin to fall like rain from the bottom of the ice tray!

Reflection: What did we learn?

We might at first think that the hot steam, applied to the ice cubes, is causing a change in state, and causing them to melt into rain.

However, if you look closely, the ice cubes are still solid, and still in their tray. The rain is coming from the bottom of the ice cube tray!

When warm, moist air rises and cools, the water vapor in the air condenses into liquid droplets, forming clouds. As the droplets continue to grow and become heavier, they eventually fall to the ground as rain. This process is called precipitation.

What is actually happening in this experiment is that the hot water vapour or steam from the saucepan is rising and hitting the cold surface of the ice-cube tray. This is cooling the steam, changing its state from a gas back into a liquid. The liquid water is falling back to the saucepan in the form of rain drops.

How Does Rain Occur?

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Summary

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