What you need

Use ordinary paper first. Keep the materials the same while comparing designs.

  • A sheet of paper
  • Scissors
  • A ruler
  • A pencil
  • One or more paper clips

Build the helicopter

Cut a paper strip about 18 centimetres long and 5 centimetres wide. From the top, cut down the centre for about 7 centimetres to create two blades.

  • Fold one blade forward and the other backward
  • Fold the lower sides inward to make a narrow stem
  • Attach a paper clip to the bottom
  • Hold it above your head and release without pushing

Observe the fall

As the helicopter drops, air pushes against the two blades. Their opposite folds create a turning force, so the paper begins to spin. Air resistance slows the fall while gravity pulls it downward.

Turn it into an investigation

Choose one feature to change and keep everything else the same. Drop each design from the same height and time several trials.

  • Make the blades longer or shorter
  • Use wider or narrower blades
  • Add a second paper clip
  • Try lighter or heavier paper
  • Compare the average falling time

Safety note

Use scissors carefully and ask an adult for help when needed. Test in a clear indoor area away from fans, stairs and other people.