This month at Ribbons & Robots we’re asking what, how, and why.
Today’s questions are:
What’s a parachute?
How does it work?
Why does it slow you down when you fall?
It might look like magic when you see a skydiver floating gently down to the ground, but it’s actually something a lot cooler than that. It’s physics.
To understand how a parachute works, there are a few words you’ll need to know:
Gravity: The force between two objects that have mass. Earth pulls everything toward it through the force of gravity.
Weight: The force of gravity on an object. This is how heavy something is.
Drag: The force of air molecules pushing against an object as it moves through them.
When you drop an object, gravity will speed it up as it falls at the same rate no matter how heavy it is. So you’d think that if you dropped two different objects at the same time that they would hit the ground together.
But is that what happens?
Test it out yourself…
They don’t hit the ground at the same time because of air resistance, or drag.
The more spread out an object is, the more air molecules it needs to push out of the way as it moves through the air, and the more it’s slowed down.
Without drag, gravity would do its thing and everything would fall at exactly the same rate.
Think of a feather and an arrow. An arrow speeds right through the air with little drag because it doesn’t catch much air. It cuts right through it.
Try throwing a feather, and you notice it just kind of floats there.
The same is true when falling. A feather will float softly down to the ground, whereas the arrow would drop straight down.
Drag is how parachutes get the job done.
They work so well that some people parachute just for fun!
A parachute is a lot more spread out than you are and will create more air resistance, which means they help you fall through the air much more softly and slowly (and safely) than you would all by yourself.
This is very important because when skydivers jump out of a plane, they’re falling faster than a race car drives!
It would definitely hurt you to fall to the ground at that speed, but did you know it would also hurt you if your parachute opened up and slowed you down too fast?
That’s why parachutes are designed to open up just right to keep you safe the whole way down. A parachute is made of 3 separate chutes packed together in a container designed to open in a controlled and safe way.
Watch these parachutes in action:
But parachutes are used for more than just fun.
NASA also uses parachutes on spacecrafts to help slow the landing and reduce wear and tear on brakes during shuttle landings.
This is a video of the chute testing for the Orion spacecraft:
Fun parachute fact:
Parachutes were technically invented by Sebastien Lenormand in 1783, but that wasn’t the first time they were thought of. Leonardo da Vinci made sketches of a parachute hundreds of years before and predicted that using it would keep a man safe when falling from any height. Da Vinci’s design wasn’t built or tested until 2000, but when it was, it worked great!
You can test out drag in your own home with objects you find around the house.
Just find two objects that are different shapes and sizes (and that won’t break if you drop them). Hold them up and let them go at the same time. Watch how they fall to the ground. The one that hits the ground first had less air resistance slowing it down.
We tried this out first with a control trial of two Legos.
A control trial is one where there are no experimental changes. It gives you something to compare everything else you test to.
On our control run, both Legos hit the ground together.
Next, we tried a Lego and a plastic bag.
And a flat sheet of paper and a balled up sheet of paper.
The plastic bag and flat sheet of paper worked the same way a parachute does – they gently floated to the ground thanks to drag.
Keep the innovation going at home with the free How to Build a Robot from A to Z digital picture book and printable paper robot building kit.