This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!
If Australia is nearly at the bottom of the world how are we the right way up? Why doesn’t our head point down? – Rudy, 5, Melbourne.
A very interesting question, Rudy!
You would think that because we’re at the bottom of the world, us Australians would be really good at handstands and standing on our heads. But in Australia, we still have our feet firmly planted on the ground.
When you hold up a ball and drop it, it always goes towards the ground, no matter where you are on the Earth.
When the ball goes towards the sky, we say it is going “up”. When it is going towards the ground, we say “down”.
It’s all about gravity
Gravity is a force (or a pull) that all objects have on other objects.
So when you stand on the Earth, the Earth is pulling you to keep you on the ground. But, did you know that you also pull the Earth up with the same force?
So the Earth pulls you down, but you pull the Earth up! That makes you pretty strong.
Gravity always pulls you towards the middle of the object.
So for the Earth, which is shaped like a ball, the force of gravity pulls you to the centre from every point on the ground. That’s why, no matter where you stand on the Earth, you always feel like the ground is at the bottom and the sky is up.
That also means that if you drop a ball it will always go toward the middle of our planet… until it hits the ground and bounces, of course.
So, why is Australia on the bottom?
The North and South Poles are what we call “relative”. They are just names for specific places on the Earth so that it is easy for us to give directions and find our way around.
A long time ago, someone decided that the pole on the top would be called the North Pole and the one on the bottom would be called the South Pole.
But, you could turn the Earth upside down and no one would really notice, because we would still feel that the ground is down and the sky as up. This is because gravity always pulls us towards the middle of the Earth.
Read more: Curious Kids: Why is the Earth round?
Fun facts about gravity
Did you know that if you were to dig a hole from one side of the Earth to any other point of the Earth, and you jumped into the hole, it would always take the same amount of time to fall out the other side?
Sir Isaac Newton was a famous scientist that came up with many ideas about forces and gravity, about light and about how things move. He was born on Christmas Day in 1642. Some say he discovered gravity when an apple from a tree fell on his head. Ouch! It might not have happened exactly that way but it is still a nice story.
The force you feel of the Earth’s gravity pulling on you is called your weight. If you were on the Moon, your weight would be six times lighter than on Earth. This is because the Moon is much smaller than the Earth, so the pull of gravity there is much less than what we feel on Earth. This is also why astronauts can bounce around like being on a trampoline when they are on the Moon.
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