Blog

Paper helicopter with paper clip weights.

This spinning helicopter is great fun!

NASA’s Ingenuity helicopter has made history by flying on Mars. To celebrate the first flight of a copter on another planet, here’s a simple unpowered helicopter you can build at home!

You will need

    • A4 paper
    • Pencil or pen
    • Ruler
    • Scissors
    • Paperclips

    What to do

    1. Using a ruler and pencil to measure on a piece of paper.With a pencil and ruler, draw a line 4 cm in from one of the short sides of the paper.
    2. Cut along the line.Use scissors to cut along the line.
    3. Take the strip of paper you’ve cut, and check the length of its sides. It should be 4 cm wide and 21 cm long. Put it on the table so the short sides are top and bottom.
    4. Mark a line half way along the top edge.Measure halfway along the top edge, and rule a line running down to the middle of the paper – it should be about 10 cm long.
    5. cut along the linesAbout 2 centimetres below the middle of the paper, rule lines coming in from the two sides. Make these lines about 1.3 cm long.
    6. Cut along the lines you’ve drawn.
    7. Fold the paper inwards where you have cut..At the bottom of the paper, fold the two sides into the middle. Put a paperclip or two on the bottom to hold the flaps in place.
    8. Fold the top pieces in opposite directions.At the top, fold one strip towards you and one away.
    9. Paper helicopter in motion. Your copter is now finished! Hold it up above your head, with any paperclips at the bottom, and drop it. The copter will spin gracefully to the ground.

     

    What’s happening?

    This spinning helicopter is great fun, but how does it work? There are two competing forces involved – gravity and air resistance.

    When you let go of the copter, it’s pulled to the ground by gravity. However, the flaps at the top push lots of air out of the way on the way down. At the same time, the air is pushing against the flaps, slowing the copter’s fall.

    This air resistance also has other effects. First, it bends the flaps back, making the whole copter more streamlined, and letting it fall faster. It also spins the copter, because the flaps are bent in different directions.

    As the copter spins, the flaps are pulled outwards by the spinning. As they spread out, the copter starts falling more slowly, because the flaps are catching more air. Catching more air makes it spin faster too!

    If you watch carefully, you can see this entire process unfold in just a second or two.

    A thought experiment

    You might wonder what would happen if you dropped this spinning helicopter on Mars. The red planet only has one third the gravity of Earth, so the copter would fall slower at first. Then, Mars only has 1% of the density of Earth’s atmosphere. That means there wouldn’t be much air resistance slowing the copter or making it spin!

    If you’re after more science activities for kids, subscribe to Double Helix magazine!

    Subscribe now! button

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

By submitting this form, you give CSIRO permission to publish your comments on our websites. Please make sure the comments are your own. For more information please see our terms and conditions.

Why choose the Double Helix magazine for your students?

Perfect for ages 8 – 14

Developed by experienced editors

Engaging and motivating

*84% of readers are more interested in science

Engaging students voice