NASA's Ingenuity, the Mars Helicopter, just flew for the first time on Mars! How amazingly cool is that?!
This may have you thinking - how do helicopters stay in the air? In this activity we will build a simple mechanical helicopter using a propeller and a rubber band.
What you'll need:
- Printed template
- 6" Plastic propeller (like this or purchase this kit)
- Popsicle stick
- Rubber band
- Paper clip
- Masking tape
First, build the base of your helicopter. Attach the propeller to one end of the popsicle stick by pushing it in place. In a helicopter, these are called rotor blades.
Bend the paperclip into an L shape.
Tape the paperclip to the bottom of the popsicle stick so that there is a hook sticking out the bottom of the helicopter.
Now it is time to decorate! Print out the template and choose which robot you would like to build into your helicopter. Cut it out along the dotted line. Or if you would prefer, you can also draw a flying robot yourself!
Tape your robot to the popsicle stick.
The last step is to stretch a rubber band from the hook on the rotor blades to the hook you created using the paper clip.
Your helicopter is complete! To use it, wind up the rotor blades so that the rubber band is twisted around and around (at least 50 times!). Hold your helicopter with two hands; one at the top and one at the bottom. Let go of the rotor blades at the top first, then let go with your bottom hand. Releasing in this way will allow you to direct which way the helicopter flies. It should be obvious, but make sure to direct it away from your face.
When you release the helicopter it should fly up into the sky!
How does the helicopter work? Like any object on Earth (or Mars for that matter!), the helicopter is pulled down by the force of gravity. To lift the helicopter, the rotor blades spin very quickly to push air downwards. This creates an upwards force called lift. The amount of lift will change based on the number of rotor blades, the shape of the rotor blades, and how quickly they are spinning.
If the force of lift is greater than the force of gravity, the helicopter will move up. If the force of lift is smaller than the force of gravity, the helicopter will move down. If the forces are equal the helicopter will hover in the air!
Mars is different from Earth. The force of gravity is smaller, which means there is less force pulling down. But the air is not as dense (it is more spread out), which means the rotor blades will create less lift each time they spin. Because of these differences, a helicopter designed to fly on Earth would need to be adjusted to fly on Mars. A huge congratulations to NASA for flying a helicopter on Mars for the first time in human history!
Try experimenting with your helicopter:
- What happens if you wind the rotor blades more times?
- What happens if you use a different rubber band (e.g. shorter, wider, more than one)?
- Can you aim your helicopter so that it lands on a target?
This activity is based on the book If: Ball, Then: Catch, available here!