Why is the sky blue Where does electricity come from How does a boat float How do we see colours How does a car move Why can’t I jump as high as this house 2
How do birds know north from south How do planes stay in the air Oh hello there friends Did you know that physics is a very important part of our everyday lives Just go for a walk and you’ll see for yourself From the wind that rustles the trees and the Sun that keeps us warm to the car that drives us around and the food that gives us energy to play physics is all around us all the time Follow me and we’ll investigate the laws of the Universe the fundamental rules that describe the nature of our world and beyond So turn the page and join me Professor Astro Cat on my ATOMIC ADVENTURE We can feel the wind but why can’t we see it Home sweet home 3
gravity On Earth there is a simple rule what goes up must come down If I jump in the air or throw a ball really high I know that the ball and I will always return back to the ground This is because of gravity which is an invisible force that pulls us down to the ground Gravity always pulls things together but never pushes things apart If there was no gravity on Earth then we would all float around which would make it difficult to eat and drink or see our friends GRAVITY KEEPS US ON THE GROUND EVERYTHING IN ITS RIGHT PLACE The more massive a thing is the more force it exerts on us We all stay on the surface of the Earth because it is the biggest thing that is nearest to us The sun is so big that it exerts a huge force due to gravity 4 This gravitational pull keeps our planets together so they don’t fly off into outer space and that is why the planets stay in orbit
KEEPING OUR MOON IN THE SKY Our Moon stays in orbit around the Earth because of the Earth’s gravity Our moon is always trying to fly away but the gravity of our Earth keeps it flying around us YAHOO ON THE MOON JUMPING ON THE MOON ground but much slower than you would on Earth Gravity is smaller on the Moon because the Moon is smaller than the Earth This means you are able to jump much higher there You would still come back down to the ON THE EARTH WHO DISCOVERED GRAVITY We know about gravity because of very curious people called scientists that explore test and think about how everything works around us Isaac Newton was a scientist who discovered how gravity works he realised that gravity was acting on everything from an apple falling from a tree to the planets moving around the Sun So before we begin our adventure let’s understand what a scientist does FOR GRAVITY’S SAKE Gravity is the reason the Earth and the Sun were created from clouds of dust and gas floating around in space Gravity started to pull them together until they collapsed in on themselves and as they fell inwards they became increasingly compact and turned into the stars and planets we see around us today
