The first way people measured time was by hanging something and seeing how it moved.
Then they compared it to their pulse.

After that came a lot of very interesting little wheels and pieces that move in the most amazing ways. Most people can’t understand but
that is how you can tell when it is time for something to happen.

Another way to know what time it is to look around. Like when the sun falls and you know is time to go home.

The sun around here is always falling at different times. But if you measure the difference between yesterday and today, then you know
how we’re moving.

The worst way to fall is to be inside a falling airplane.

Some people like to jump off airplanes, because when you are free-falling your brain thinks that you are flying.
So then you start having fun, looking around and playing. But then you remember that you are not flying so you have to pull on a string in order to stop flying and start falling.

Falling is better than flying because at least then you end up alive.

The same happens underwater. Some people learn to hold their breath and go very deep. They are trained to be very relaxed so that this is possible.

They stay above the water for a while, and try to get very relaxed. When they are very sleepy, they just let go and sink all the way down. They sleep their way down, and they sleep their way up.

Sleeping is better than floating, because if you remember that you are floating then you end up breathing water.

fish breathe water, but when they’re dying they start swimming sideways.
gravity makes them float.

Sleeping looks like being dead or like sinking upwards.