You’ll need

  • An empty, clean jar with a metal lid
  • A hammer and nail
  • A dark room – try doing this experiment at night so you can just turn the lights off to make the room dark
  • Warm tap water
  • Boiling water
  • Oven mitts
  • Ice cubes
  • A torch

 

What to do

Warning!

This activity uses a hammer and nails, boiling water and a glass jar. Adult supervision is needed, and they will have to do some parts of the experiment for you.

  1. Gather your materials on a flat surface. Make sure you use a room that you can make dark.
  2. Ask an adult to push small bumps into the upside down lid of the jar using the hammer and nail. The bumps should be sticking out from the top of the jar lid. Be careful not to poke holes through the lid!
  3. Add some warm tap water to the jar, swirl it around and then throw it out. You do this so the jar doesn’t crack during the next step.
  4. Pour about 5 cm of boiling water into the jar. Don’t touch the jar – it will be very hot! If you need to touch the jar, make sure you use oven mitts.
  5. Place the lid of the jar upside down on top of the jar. Make sure it’s completely covering the mouth of the jar. Allow it to sit for several minutes.
  6. Put the ice cubes in the upside-down lid.
  7. Turn off the lights. Shine a torch through the jar to watch what happens.

Questions to ask

Will the jar make rain if you don’t use boiling water? Try the experiment again, but put different temperatures of water in the jar.

How important is the ice on the jar? Try it again, but don’t put ice on the jar lid.

Can you make it rain without making bumps in the lid? Try it again with a jar lid without any bumps in it.

What's happening

Steam rises off the boiling water. It hits the cold lid, cools down, and turns back into water. This is called condensation. The water runs down the bumps in the lid and collects into drops at the tips of the bumps. As the drops get bigger and heavier, they fall, and it rains inside the jar.