have this huge turntable where you can

sit, and perform experiments. Like in the

middle of the turntable you can put some

water and then add liquid nitrogen, and

this creates a kind of fog these tiny

water droplets that spread out from the

middle, but because the actual linear

speed of this turntable is increasing

the further out you go well, the vapor

falls further and further behind

creating a swirl, that looks a little bit

like a Hurricane. And that analogy is not

by accident, the Earth is after all one

giant turntable, and the weather patterns

we get are a result of that. When you

study Physics in rotating frames of

reference, or even just rotating bodies.

You find some pretty mysterious and

counterintuitive phenomena, which is why

I'm dedicating this video to four

revolutionary riddles. Number one here I

have a ramp, or an inclined plane and

just to show you i'm not doing anything

funny with it, if I just let a roll of

tape go it will accelerate down the ramp.

But! Here I have a mystery cylinder, and

I'm going to place that on the ramp, and

we will see that it rolls, and then it

stops, and then rolls, and then stops. So my

question to you is. What is In the

mystery cylinder? What is this object?

Number two, take a bicycle and have

someone support it, so it doesn't fall

over or lean it up against something, and

then take a bit of string and tie it to

the bottom pedal. Now what I'm going to

do is pull backwards horizontally on

this string, and I want you to predict

what the bike will do. Will it go

backwards? Forwards? Or will it just stay

there and not move. My intuition would

tell me that it would go forward? I think it

might not move if you're going to be

pulling backwards from a stationary

point on the pedal, you're going to be

pulling it backwards just as the pedals are tying to

spin the wheels forward, so maybe

it might not move. Things gonna go

forward, I'll go forward. Sure? Yeah, I'm

sure. all right three, two, one.

Number three. I want you to think about running two laps of

this track now the first lap you can go

as slowly as you like, let's call that

speed V1. But on your second lap, I want

you to run faster. Such that the total

average speed for both laps combined is

twice V1, twice the speed of your first

lap so the question for you is. How fast

do you have to run that second lap, so that

your total average speed, is two V1?

Number four, any time a train is moving, either

slowly or very fast. There is a part of

the train which is actually moving

backwards with respect to the ground,

that is not backwards with respect to

the train, and it doesn't have to be

going so slowly that if you ran

backwards you would be going backwards

with respect to the ground. It is at any

speed, any normal train will have a part

of it, which is moving backwards with

respect to the ground. My question to you

is. Which part is it? now with these four

riddles, you can make me a video response

if you like to tell me about your

solutions to them. Or you can simply

leave your answers in the comments below

and number them 1 2 3 4 so we know which

ones you're talking about, and I will

post all of the answers up and next week

at the same time same place.

All of my videos are made possible by my Patrons

on Patreon, so if you are one of those

people. Thank you so much for your

ongoing support, and if you're not. Maybe

now is a good time to consider becoming

one, if you go to Patreon.com/Veritasium

you can support me there.

Otherwise, if you're interested in more

riddle-y puzzling things, you can check out

my Spinning tube trick, my 5 fun physics

phenomena, and say the spinning district

and if you haven't subscribed Veritasium

already I highly recommend you do that.

And since i'll be posting the answers

next week I would like for you to ring

the bell down below, and that will make

sure that you're notified

when my videos come out. So as always,

thanks for watching wait that's, that's

Michael's line.