How to explain sleeping in using physics?

It's really not my problem that I always want to sleep in

Because...

(Now my mother no longer has to worry about me staying in bed

Experimental equipment

The marked cup, scissors, A4 paper, ruler, small ball (other items can be used instead)

Experimental procedures

First, we put the ruler in a critical state where it is about to fall.

Use a lighter ping-pong ball to drop vertically onto a ruler.

You can see that the ruler is overturned.

Replace the ping pong ball with something heavier

The ruler unexpectedly "turned over" again

Then, we cover the ruler with A4 paper

Then a ping-pong ball hits the ruler

The ruler does not move

Because table tennis balls are too light

To increase the difficulty

Later we used heavier balls

The ruler remains stable on the table

Is it because A4 paper is too heavy?

We fold the A4 paper into small pieces

Place on ruler

When the ball hits the ruler

The A4 paper flew out.

Cut the edges of the A4 paper into jagged shapes

When hit, the ruler remains motionless

Play back in slow motion

We can see the moment of impact

A4 paper is like a quilt

Tightly tied the end of the ruler

Just like us who can't get out of bed in the morning

We cut the A4 paper into the same width as the ruler

Hit again

The ruler was overturned

We had an idea

Cut a space in the middle of the A4 paper

Show the end of the ruler

When it hits again

The ruler fell to the ground

Just like that, we found the solution to the problem of not being able to get out of bed!

Just cut the quilt shorter

Or hollow out the middle of the quilt.

Waking up is easy

Mom doesn't have to worry about my studies anymore~

Principle Explanation

Let's first understand Boyle's law:

This law explains the dependence of pressure and volume in a closed container. As the volume increases, the pressure decreases.

In the experiment, when a complete A4 paper is covered on the ruler, the four sides of the A4 paper can be regarded as being tightly attached to the table, and it is difficult for air to enter the inside of the paper. When the ruler is hit and the end is tilted upward, the A4 paper is lifted up, causing the volume inside the paper to increase and the pressure to decrease. The atmospheric pressure outside the paper is higher than the pressure inside, so the paper is pressed tightly against the ruler.

When we make a hole in the middle of the paper or reduce the width of the paper, the curling of the ruler will cause the edge of the paper to curl up, which can easily introduce air into the inside of the paper. The pressure inside and outside remains consistent, and the ruler naturally falls to the ground.

Editor: Litchi

Source: Institute of Physics, Chinese Academy of Sciences