Hello Explorer, welcome along. The Fun Kids Science Midweekly is here. My name is Dan. This is your quick bite-sized science special on a Wednesday. This week, you can find out why roller coasters are so fast at the start. Also, why your teeth chatter when you're cold. We'll search for the lost city of

Atlantis and discover how plants grow underwater. And we start in Scotland. Jack, thank you for this.

Jack wants to know, why do roller coasters get so much speed at the start? Well, roller coasters get speed

normally in two different ways. They either use gravity where you are winched, you are cranked

and dragged to the top of a huge hill by a chain and then let go and gravity takes over.

That's quite old school. You might have been on one.

You've got that slow start as it creeps up the hill. Over the last 10 years or so, there's been

another way of making coasters race. And that's using something called hydraulics, where a lot of gas

is squeezed into a tiny amount of space. Then it gets released to power a

motor. The force of the gas makes the motor turn. It makes the pistons move. And a cable is attached

from the motor to the car. When all that gas goes, it's at such a high force, it flings the car along the track

and it makes you get extremely fast right at the beginning. That's one way. There's also a method

that uses magnets, where it switches magnets on and off, alternatively, which gives you the power because the force of the magnet pulls you along

to creep up and to fly and to fling and to go really fast, Jack. Thank you so much for the question.

Let's go to Rowan who wants to know, why do teeth chatter when you're cold?

When you're chilly, your body does everything it can to try and raise your body temperature. It makes the muscles all over your body twitch and spasm,

which is why you shiver. Now you shiver to warm up your body temperature. It moves your muscles to warm up the

tissues, to lift your temperature, to make you a bit hotter, and your teeth chatter as a result of

that shivering. So your brain is saying, oh, I'm really cold right now. I need to get a bit warmer.

So it moves all your muscles, it moves the muscles around your jaw just to generate some heat energy. And because of that, your teeth end up chattering, Rowan.

Thank you very much. Proper sciencey, nice and simple. I love it. This is a kind of sciencey.

From her Simon, who wants to know, is the Lost City of Atlantis real?

...