What you’ll need

  • Paper, e.g., from an old brochure, magazine or print paper
  • A ruler
  • Two coloring or felt-tipped pens
  • Scissors
  • Paper clips
  • Optional: sycamore seeds

How to do it

1. Using a pen and ruler, draw the template you see in the photo on a piece of paper. The numbers show you the length of the sides in centimeters.

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2. Cut the paper along the green lines.

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3. Now fold the paper along the red lines. First fold in the two strips at the bottom to make a narrow strip.

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4. Now fold the two strips at the top along the red lines in the opposite direction.

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5. Attach a paper clip to the end of the narrow strip. Your helicopter is now ready.

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6. Climb onto a small stool or your bed, hold your arm up high and let the helicopter fall, with the narrow strip and the paper clip pointing downwards. What happens? What happens if you let the helicopter drop upside down? What happens if you remove one of the wings?

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7. You could also try the following: Make several helicopters of different sizes and using different paper. Try out these helicopters and see which one flies the best.

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Well spotted!

Initially, the helicopter falls towards the floor. But suddenly it starts to rotate around its own axis and spirals slowly towards the floor. The double samaras of the maple tree also rotate the same way. If you have some, why not give it a try?

What's the secret?

A real helicopter flies because it has a motor that turns its rotor. Due to the shape and movement of the rotor blades, the air pressure above the rotor blades is lower than the pressure below them. When the helicopter’s rotor turns, this generates lift which allows the helicopter to fly.

Your helicopter does not have an engine to make the “paper rotor” rotate, so it works the other way around. It drops to the ground because of the force of gravity. As it falls, the air presses against the rotor blades. As the rotor blades are offset, this causes your helicopter to rotate around its longitudinal axis. In fact, a better word than helicopter would be “dropcopter.”

The way in which sycamore seeds* fly is similar: First, they fall downwards, seed first. Then suddenly they lie flat in the air and start to rotate around their own axis. How does this help the sycamore seed? Because it has such an ingenious design, it takes longer to fall to the ground and has more chance of being carried by the wind. The more places the seeds land on, the higher the probability that some of them will germinate and new trees will grow.