A man picked up a plastic water bottle and filled it to the rim with water. He put a ketchup sachet in it and closed it up.
The man approached a woman and said, “If you can solve how this works, I’ll give you a dollar.”
The man said “down” and the sachet of ketchup suddenly went down. Then he said “up” and it went up. Then he said “down”, and when it was halfway down, he said “stay” and it stayed.
How did he do this?
Answer
He did it by adding pressure to the bottom. When there is less pressure, it rises. When there is more pressure, it lowers. If you add just the right pressure, it will stay.
You can perform this with lots of practice in front of a mirror. It will shock your friends, most likely.
You can find a ketchup sachet at your local fast food restaurant (ex: Burger King, McDonald’s, etc.)
