Steam Powered Can

Let off some steam with this fun activity! Use the power of steam to make a can perform amazing acrobatic moves. Who will get dizzy first, you or the can?

Australian Curriculum links

  • Science > Physical Sciences > Year 3 > ACSSU049
  • Science > Physical Sciences > Year 4 > ACSSU076
  • Science > Physical Sciences > Year 7 > ACSSU117
  • Science > Earth and Space Sciences > Year 7 > ACSSU116

You'll need

  • can of soft drink (full and unopened)
  • nail
  • bucket of water
  • string (1 metre in length)
  • lighter or matches
  • gas burner, Bunsen burner or candle

Try this

Safety precaution: This experiment should be performed with adult supervision. Objects will become very hot in steps 8 and 9 of the experiment.

  1. Holding the can over a bucket or sink, use the nail to make a small hole in the middle of the long side of the can.
  2. Push the nail into the hole. Turn the nail to the right until it lies flat against the can. In this way, the metal of the can is twisted to create a hole facing to the right.
  3. Make a second hole on the opposite side of the can. Again, turn the nail to the right until it lies flat against the can to create a hole facing to the right.
  4. Drain all of the soft drink from the can (it may help to blow through one of the holes to force the soft drink out of the other hole).
  5. Hold the can on its side with one of the holes facing up and lower the can into the bucket of water. Push the can into the water and quarter-fill the can with water. This will take some time as the water will enter through the small hole made using the nail.
  6. Remove the can from the bucket.
  7. Tie the string to the ring-pull at the top of the can to allow the can to hang vertically when suspended by the string.
  8. Use the lighter or matches to light the gas burner, Bunsen burner or candle.
  9. Hold the loose end of the string and hang the can over the flame until the water boils and the can spins.
  10. Place the can in the bucket of water or in a sink to allow it to cool.
  11. Turn off the gas burner/Bunsen burner or blow out the candle.

What's happening?

The flame heats the water inside the can until eventually the water starts to boil. When water boils it changes from liquid water into steam. The steam inside the can builds up pressure and starts to push out through the holes in the side of the can. When the steam is moving fast enough out of the holes, it causes the can to move in the opposite direction and the can starts to spin.

Water exists in three states, solid (ice), liquid (water) and gas (water vapour). When enough heat is added to or removed from water, it will change between these states. In this activity, heat is added to liquid water, causing it to boil and evaporate to form gas (water vapour). Water that has been turned into a gas by boiling is commonly known as steam.

Steam takes up a lot more space (it has a greater volume) than liquid water because water molecules in steam are more widely dispersed. There is a lot of empty space between the water molecules in steam and the molecules contain more energy and move more rapidly than do the molecules in liquid water.

As the water in the can turned into steam, the steam filled the can. The pressure inside the can increased as more and more steam was produced. The holes in the can were the only spaces through which the steam could escape. The holes were bent at an angle to direct the flow of the steam. According to Newton’s Third Law of Motion, every action has an equal and opposite reaction. When the steam pushed out of the can in one direction, the can was pushed in the opposite direction, so the can began to spin.

Real world links

The pressure created when water turns into steam can be harnessed to make something move. In the Industrial Revolution, early locomotives, steam-boats and factories were powered by steam. The ‘choo-choo’ sound associated with trains is made by steam-powered locomotives. When the exhaust valve of a steam-powered locomotive opened, it released the train’s steam exhaust under great pressure, making a ‘choo!’ sound.