Stepping Into Science is a new series where we will explore exciting science from A-Z. There will also be activity ideas accompanying each post to extend your child’s learning.
Imagine this: You have just won a pair of VIP tickets to this year’s Halloween Horror Nights.
How would you react? If you are a fan of haunted houses and spooky scares like me, you would be jumping up and down, running and screaming ecstatically around the house. You might also have noticed that right after jumping up, you would land right back onto the ground.
Why would you land back onto the ground instead of staying afloat in the air? This is due to an invisible force acting upon your body, known as gravity.
What goes up must come down.
Oops, this ain’t gonna be the title of the next chart-topping music single.
This phrase was coined by Sir Isaac Newton when he discovered the law of gravity. Objects that rise must eventually return to the earth due to gravity.
Legend has it that he made the now famous observation of an apple falling off the tree more than 300 years ago during his hiatus away from school due to the bubonic plague epidemic in 1665. It was during this observation that he questioned why the apple fell straight down, rather than falling sideways or moving upwards.
Why is the discovery of gravity important?
Newton discovered that the force which made the apple fall and holds all of us down to earth is also the same force that keeps the moon and planets in their orbits. While this discovery of the law of gravity by Newton may seem minor compared to many other important discoveries out there, it has helped generations of scientists, engineers and astronauts understand and develop space travel.
Did you know?
The relationship between the attractive force of gravity and the masses of two objects was all it took for NASA to calculate a safe trajectory to carry out the Apollo Missions to the Moon.
What happens if there is no gravity on Earth?
If gravity was a switch that could be turned on and off, what would happen on Earth if the switch flipped, even for just a few seconds?
Without gravity, there would be a devastating impact on Earth and our lives. Everything on Earth will be lifted off the ground instantly. Cars, trees, buildings, water bodies and even you and me will be sent floating about in the air. Coupled with the fast rotation of the Earth on its axis, everything will be sent on a wild tumbling ride around the planet.
Now you may be wondering, what about the air around us? Well, without gravity, there would be no force acting upon the Earth’s atmosphere. All the gases would float into outer space. This means there would be no oxygen for you and me. Not as fun as we imagined, huh?
Suggested Activity for Children
Now that we have a better understanding of gravity, let’s explore the effects of gravity on items when dropped from a height.
– Small ball e.g. tennis ball
– Lightweight object e.g. cotton ball
1. Pick up a small ball and hold it in your hand.
2. Hold the ball at a height above your head and let it fall to the ground.
3. Next, pick up the ball and throw it to your left. Observe what happens.
4. Now, pick up the ball and throw it to your right. Observe what happens.
Repeat 1-4 with a cotton ball.
What did you and your child observe when dropping both objects from a height and in different directions?
When comparing a tennis ball and a cotton ball, it doesn’t matter how heavy an object is. When you let go of an object from a height, the object will always fall to the ground. You would also have noticed that whether you drop the object towards the left or right, it will eventually be pulled back down to the ground.
I think that’s enough gravity for today. Now, let’s drop it and have some fun out there!
Written by Lah Jia Min
Featured image illustrated by Jarrod Chua, Spaceytales