This 15min STEM activity is incredibly easy to resource; all you need are the helicopter templates, paperclips and scissors! Here’s our review of the activity…
We began the session by comparing the images of a helicopter and an aeroplane and discussing their differences. The children observed out that:
- aeroplanes have wheels but not all helicopters do
- helicopters are much noisier than aeroplanes
- aeroplanes have fixed wings but helicopters have spinning rotor blades
We then spent a few minutes focusing on answer three. I explained that aeroplanes have jet engines that are designed to move the plane forward at high speed. This speed makes air flow rapidly over the wings which push it down towards the ground, creating an upward force called ‘lift‘. Aeroplanes take off horizontally by moving along a runway at a very high speed until they create enough lift to take off. Meanwhile, helicopters take off and land vertically. The helicopters engine turns the rotor blades at a very high speed until the helicopter creates enough lift to take off. Whilst aeroplanes have to move quickly through the air to create lift, helicopters can create it by spinning their rotor blades fast, allowing them to move vertically straight up and down.
Sharing this ‘real-world’ context then led into our paper helicopter activity. Each child was given their template to cut out and drop from a height (we stood on chairs). They were then challenged to add a paperclip to the bottom of their helicopter, dropping it to see what happened. After each drop, the children should add another paperclip and observe the changes.
After needing a bit of assistance to cut and fold their helicopters correctly, the children loved dropping them and were impressed with how well the blades rotated. Some of the helicopters fell at an angle but this was soon corrected with a quick adjustment of the blades. In fact, by changing the position of the blades, we learnt that we could change the rotation of the spin to clockwise/anti-clockwise. The children quickly spotted the correlation between adding paperclips and increased speed. They also observed that once they had added lots of paperclips, the helicopter fell straight to the floor without spinning.
Then it was time to explain the science behind it. I explained that gravity is the force pulling the paper helicopters to the ground. As it falls, air resistance is the opposing upwards force. Air resistance happens when an object moves through a layer of air and collides with air molecules. We can feel air resistance when we stick our hand out the window of a moving car. The more air molecules an object collides with, the greater the air resistance.
In our paper helicopter experiment, adding more paperclips reduces the air resistance because the added weight of the helicopter pushes the air out of the way faster, causing it to fall quickly to the ground.
A common misconception that the children are likely to make is that heavier objects fall faster. However, this is not the case. A great way to extend this activity with older children is to ask them what they think would happen if there was no air resistance. The classic ‘bowling ball and feather’ experiment is a great example of this. Here’s a great video of this in action that could be used as a starting point. Click here to watch it.
If you’d like to try this for yourself then you can download our 15min STEM paper helicopter activity here.