Gravity is the force that pulls all objects toward each other. Every object has gravity, an invisible force that pulls things toward its center. The bigger the object, the greater the gravitational force. The Sun is huge, so gravity keeps the planets in our Solar System orbiting it. The Earth’s gravity controls us and everything around us on its surface.
But this doesn’t mean that the sun’s gravitational pull will pull the planets towards it. The sun’s gravity is met by the planets’ speed which stops them from moving toward the sun. The sun’s gravitational pull and the planets’ velocity are balanced, which keeps them in orbit.
Read on to find out:
- Why gravity is important in everyday life;
- Who discovered gravity;
- What is the measure of the force of gravity;
- Which planets have gravity;
- Why gravity is different on different planets;
- Ten interesting facts about gravity for children.
Gravity is a pulling force exerted by the Earth on falling objects, causing them to move toward the ground. It feels like it is pulling ‘you down,’ but that’s because wherever you are on Earth, it is pulling you ‘down’ toward Earth. Your feet are still on the ground, and because of gravity, ‘down’ feels the same wherever you are on Earth. So you could be in the Northern Hemisphere in Europe or the Southern Hemisphere in New Zealand.
Why is Gravity Important in Everyday Life?
Gravity is very important in our everyday lives. The Sun’s gravity keeps the Earth in orbit, and the Earth’s gravity keeps it the right distance away from the Sun. Without gravity, anything you tried to place on a table wouldn’t stay there — imagine trying to eat from a plate if the plate and food were all floating! Without the Sun’s gravity, the planets in our solar system would move around chaotically. If the Earth got too close or too far from the sun, we would not be able to survive.
Can you imagine any daily actions that would be easier without gravity? For example, we wouldn’t have to exert ourselves lifting heavy objects or climbing stairs – but this wouldn’t necessarily be a good thing. Gravity is important in keeping us strong and healthy in everyday life. The constant pull of gravity creates resistance that our bodies must work against, increasing our muscle and bone mass. If a lack of seriousness weakened these, we would be frail. It means that astronauts in space who are living in zero-gravity conditions have to take exercise every day so that they don’t become weak.
Who Discovered Gravity?
We’re all aware of it now, but which scientist discovered gravity? Sir Isaac Newton discovered gravity and defined it. He was an English scientist, mathematician, and natural philosopher who lived from 1642 to 1727. You can click the link above to learn about the scientist who discovered gravity.
But how was gravity discovered? Legend has it Newton was hit on the head with an apple, which is how he discovered gravity. It isn’t quite true, however. He did see an apple fall from a tree, but rather than hitting him on the head, it got him thinking, and that’s how he worked out that some force must exist to have pulled the apple towards the ground — and so he eventually discovered gravity.
Newton was not the first to notice gravity, but he was the first to answer the question, ‘How does gravity work?’
So, how was gravity discovered? Newton performed many experiments, and he eventually figured out that gravity’s force depends on how heavy objects are and how far apart they are. The heavier an object, the stronger its gravitational pull. The further away from that object, the less we would feel its gravitational pull.
Another scientist who helped answer the question, ‘How does gravity work?’ and defined gravity was Albert Einstein. Einstein discovered that gravity affects not only mass but also light. When you shine a torch upwards, the light will turn redder because it is pulled at by gravity. Our eyes can’t see it, but this change can be measured.
Black holes have so much mass that they can pull anything, including light, toward them with such strong gravity that nothing can escape.
Sadly, the answer to the question, ‘how does gravity work?’ is that nobody fully knows yet. But we might find out one day with more space exploration and experiments. Until then, we can thank Newton and Einstein for helping to discover gravity!
What is the Measure of the Force of Gravity?
Defining gravity for kids? They’ll have to understand how we measure gravity to understand it fully. Isaac Newton and his findings have given us the knowledge to calculate the measure of the force of gravity. The unit of energy we use is called the Newton (N) — unsurprisingly! The measure of the force of gravity can be calculated using a formula which is: mass x acceleration.
The Earth always produces the same acceleration on every object. If you drop something small like a peanut or something big like a table, they will gain velocity (speed) at the same rate. Despite the gravitational force is different, as are their masses, the acceleration is the same. The Earth’s gravitational force accelerates objects when they fall; it is constantly pulling and the object’s speed up.
The weight of an object is the force caused by gravity pulling down on the object’s mass. Weight is measured by using a force meter. The bigger weight attached to the force meter, the more the spring inside will stretch.
What is the Relationship Between Gravity and Distance?
So, we know what gravity and distance are separately, but what is the relationship between gravity and distance? Well, the amount of gravity an object possesses directly correlates to its mass and the distance between it and another object.
The first person to discover the answer to discover the relationship between gravity and distance was Isaac Newton. Newton came up with the law of universal gravitation, which states the force (F) of gravitational attraction between 2 objects with mass 1 and 2 at a distance (D). The universal gravitation equation is:
F = G(mass1*mass2)/D squared.
(G represents the gravitational constant, which has the same value throughout our universe.)
Albert Einstein’s theory of relativity can be used to add to Newton’s thinking on gravity and distance. The theory of relativity states that objects with a large mass change the form of the space around them, which, in turn, causes light to deflect into them. It has never been proven, however. Another of Einstein’s theories that remains unproven is that gravity can travel in waves.
The work of scientists more recent than Einstein is really helpful in determining the reason behind the relationship between distance and gravity. Scientific theory states that distance is proportional to gravity because everything with a mass emits tiny particles called gravitons. These gravitons cause gravitational attraction; the more mass an object has, the more gravitons there are. This theory is known as Graviton Theory. Graviton theory can also explain the differences in gravitational attraction over distances. The majority of gravitons exist in a cloud around the object. As the distance from the object gets larger, the density of the graviton cloud decreases, meaning less gravitational attraction.
What is mass?
Mass is the word used to describe the amount of matter in something. To find out how much mass there is, we weigh things. Typically, the more matter there is, the more something will weigh. It is typically the relationship between matter and size, but some exceptions exist.
People can confuse mass and weight, often assuming they are the same thing. However, there is a big difference between the two. The difference is that mass is the amount of matter in an object, while weight measures how the force of gravity acts upon that mass.
Which Planets Have Gravity?
Everything with a mass also has gravity — even people — but only things as large as celestial bodies have enough gravity for us to feel it. It is also why gravity is different on different planets. For example, all of the planets in the
All of the planets in our solar system have gravity. Gravity is what formed the stars and planets in our solar system. Atoms have gravity, which means that they pull things toward them. After the Big Bang, gravity made atoms clump together to form stars and planets.
Why is Gravity Different on Different Planets?
The strength of gravity changes with the mass of a planet, meaning that gravity is different on different planets in our solar system. When a planet is larger than Earth, like Jupiter, the force of gravity pulling things towards its center is stronger than it is on Earth. So although the weight of an object (or a person!) doesn’t change on each planet, it would feel lighter or heavier on different planets depending on the planet’s mass. For example, things would feel heavier on a planet that is smaller than Earth, like Mars.
We know that the Moon has a much lower surface gravity than Earth. If the Moon had a stronger gravitational pull than Earth, how would the astronauts have been prepared to handle this? What would be different if they — and everything they took from Earth — weighed more on the Moon?
10 Interesting Facts About Gravity for Kids:
Here are a few interesting facts about gravity for kids that are brilliant for dropping into your science lessons. They can help children understand how important gravity is for our existence and encourage them to think about how gravity affects their day-to-day lives.
- We can measure the power of gravitational force on a person or object in units known as “g-force.” For example, suppose you’re sitting down at home. In that case, you should currently be experiencing 1 unit of g-force or 1 G. This is the standard amount of gravity applied to any stationary object on the Earth’s surface. It’s what keeps us all from floating off into the sky!
- The gravitational forces we experience can be increased mechanically. You’ve probably felt a funny feeling in your tummy before when you’re in a car that stops suddenly or goes over a bump at high speed. It’s even more noticeable when you’re on a plane taking off or landing or on a rollercoaster. This feeling is caused by an increase in the g-force you’re experiencing. It effectively makes your body heavier than it is under normal gravitational forces. If you’re experiencing 2Gs, your body will feel twice as heavy as it normally does, even though it stays the same size.
- You’ve probably experienced g-forces that are higher than normal before. One of the surprising facts about gravity is that the effect it has on you increases whenever you work against it. It means it improves when you jump, for example. In addition, its effect can be increased through the use of machinery. For example, the peak amount of G-force experienced when taking off in a standard commercial airplane is around 1.4G. It means you’ll feel about 40% heavier during take-off than normal. That’s what causes that strange feeling in your tummy!
- Racing drivers regularly experience high levels of g-force. For example, Formula One drivers regularly share around 6G when taking fast corners or braking. That means that they’ll feel 6 times heavier than normal! To help them withstand these pressures, drivers must do special exercises to ensure that weaker areas, such as their necks, can withstand the pressure.
- The more mass an object has, the more gravitational pull it will create. It means that planets with more mass than Earth produce greater gravitational forces. For example, the planet with the highest gravitational pull in our solar system is Jupiter. The gravitational force applied to a stationary object on Jupiter is around 2.5 G. This means that you’d feel two and a half times heavier on the surface of Jupiter than you do on Earth.
- The less mass an object has, the less gravitational force it will produce. It is why if you look at footage of astronauts on the moon’s surface, they seem almost floating. It is because the moon has much less mass than the Earth and so doesn’t have as strong a gravitational pull. The moon has around 6th of the gravitational pull Earth does, or 0.16 G. This means that you’d feel 84% lighter on the moon’s surface!
- The moon’s gravity causes the tides on Earth. The Earth’s gravitational pull is far greater than the moon’s; that’s what keeps it orbiting around us. Despite this, the effects of the moon’s gravity can still be felt on Earth. Perhaps most notably, the moon’s gravitational pull causes the sea’s tides to rise and fall throughout the day gradually.
- The sun is the object with the most powerful gravitational pull in our solar system. It produces a gravitational force of 27.9 G, nearly 30 times that of the Earth. The sun’s gravity keeps the Earth and all the other planets in the solar system orbiting the sun. Without it, all of the planets in the solar system would crash into each other or float off into space, making this one of the most important facts about gravity.
- Black holes have the most powerful gravitational pull in the universe. These are incredibly dense objects in space, which scientists believe are caused when very large stars explode. They produce so much gravitational force that they can suck in planets and stars. Their gravitational pull is so powerful that not even light can escape them. Some scientists have theorized that they could even suck in time with their gravitational force! Scientists have theorized that an average black hole can produce gravitational forces of 153 trillion G.
- People grow taller without gravity. For example, people become about 2 cm taller in space without the pull of Earth’s gravity.
Try dropping a few interesting facts about gravity for kids into your classes to help keep pupils engaged and attentive.
The Sun and Moon’s Gravity
The Sun is huge, so gravity keeps the planets in our Solar System orbiting it. The Sun’s gravity is 274 m/s².
We know that Earth’s gravity is stronger than the moon’s because Earth is bigger than the moon.
The Moon’s gravity is one-sixth of Earth’s gravity, so an object with the same mass will weigh differently on Earth than on the Moon. The Moon’s gravity is 1.6 m/s²
This astronaut weighs 120 kg on Earth. So even though the astronaut doesn’t change size or mass, their weight on the Moon would be just 20 kg.
What is Zero Gravity?
Even when astronauts are in space, they are still affected by gravity from the Sun and planets. Again, it is because there’s a tiny bit of gravity everywhere in space.
Zero gravity is not quite the correct explanation for this. Instead, it is microgravity — meaning there is a tiny bit, but not none.
When things, including astronauts, are far enough away from a planet, they are only affected a little bit by gravity from that planet. It means they float around and are not dragged back to the planet’s surface, as the gravity isn’t strong enough from that distance.
Why Do Astronauts Float in Orbit Inside The Space Station?
Astronauts are experiencing ‘weightlessness,’ which is due to the speed they are traveling. It’s more like being in free fall. Do you know that moment you reach the top of a fairground ride or the top of a trampoline bounce before you start coming down? Well, that’s a moment of weightlessness.
