Science Around Atlanta: Physics & Roller Coasters
Hello girls and boys! Professor Labcoat here!
In my last blog post, I said, “No matter what you’re interested in or what question you have, there’s probably a scientist somewhere trying to figure it out.” That’s very true, because science is a way to learn about the world around us and everything that’s in it. There are all different kinds of scientists who are interested in all different kinds of things! You can learn more about almost anything that you’re interested in by using science.
The other day, my friend Cayce got to go to Six Flags Over Georgia to try out their Batman: The Ride roller coaster…backwards! She had a lot of fun, and even got a video of her on the ride! I decided that it’d be fun to use her video to talk about the science we can learn from roller coasters.
When I was a kid, I wasn’t a big fan of roller coasters, but I like them more and more these days. Roller coasters do some pretty cool things. They can go very fast, turn upside down, and make you dizzy very quickly. It seems pretty complicated at first, but science can help us to understand complicated things!
To figure out roller coasters, we need to think about things called “forces”. A force is a push or pull on something, and this can happen in a lot of different ways. When something pushes or pulls on something else, we say it’s “applying a force”. For example, if you push someone on a swing, you are applying a pushing force to them. If the wind blows your hair around, that’s a force the wind is applying to your hair. And you’re stuck to the ground because the earth’s gravity is applying a force pulling you downward!
Some kind of force is needed to make something start to move, slow down, or change direction. We might not always realize this is what’s going on, however, because forces can show up in places that we don’t always expect.
For example, if you throw a beanbag, you push on it with your hand to apply the force to get it to start moving. Once the beanbag leaves your hand, it’s not getting any more force from you. There are still forces on the beanbag, though, and these forces work against the force of your throw! One force is a push back from the air the beanbag is moving through. This slows the beanbag down a little bit. Another force is the force of gravity. This pulls the beanbag towards the ground. Finally, when the beanbag hits the ground, the ground applies a force that stops it from moving!
This all seems very normal to us because we deal with these kinds of forces in our everyday lives. It took scientists a long time to figure out all of these forces are happening, because everybody was so used to them! But, if you were an astronaut in space far away from the earth with no air around you, no ground under you, and no gravity to speak of, and you threw a beanbag, it would keep going in a straight line for thousands of years! It wouldn’t have any other forces around to change how it moved.
So, what does this have to do with roller coasters?
A person riding a roller coaster, such as my friend Cayce, moves in a lot of different directions at different speeds. All these changes in speed and direction mean that there are a lot of forces changing the way the person is moving. When we ride a roller coaster, we feel these forces as pushes and pulls from the straps on our seats.
One of the most important forces for roller coasters to work the way they do is the force of gravity. Just like our beanbag example, where the force from your hand gives the beanbag the push to get it started, gravity provides the force that moves you around on a roller coaster. You see, there are no motors or engines on roller coaster cars. What happens at the start of almost every roller coaster is the ride pulls you up a tall hill, and then pushes you off the edge. You can see this in Cayce’s video: at the beginning, she and her sister slowly move up a hill. The moment they start moving after that, the only force that’s making them move faster is the force of gravity pulling them down!
The first hill of a roller coaster is always the tallest part of a roller coaster, because after gravity starts to pull you around, it won’t be able to make you move to a taller place than where you started. In much the same way, if you drop a bouncy ball (without throwing it at the ground!), it will never bounce higher than where you dropped it.
Roller coasters are designed to make sure that the forces they apply to the riders aren’t enough to hurt them; this is a big part of the reason why you have to be a certain height to ride roller coasters! The seats are designed to make sure that they push and pull on the right parts of people. When roller coasters go upside down, the forces applied to the riders make sure that gravity can’t pull them out of their seats. And, sometimes on roller coasters, as the forces are changing around, you don’t feel any forces at all! This is called feeling “zero-g”. The “g” stands for “gravity”, and this means that you feel weightless. A feeling of weightlessness is what astronauts in the International Space Station experience! It’s only during special occasions that we get to have that sensation on the earth, which is one of the reasons roller coasters and other fun amusement park rides are so exciting!
I hope you enjoyed learning about roller coasters with me, and I look forward to talking about all sorts of other things with you in this space. Take care!