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NASA website with heaps of interesting facts on the moon, including up-close 3D images and how NASA is sending people there to stay by 2024!!

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Overview The brightest and largest object in our night sky, the Moon makes Earth a more livable planet by moderating our home planet’s wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years. The Moon was likel…

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Gravity vs Air Resistance
-great explanation!

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Have a look at these bits of trivia, might be good to include some to make our presentation more interesting. _Kate_

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Interesting Gravity Facts - Acceleration, G-Force, Mass, Formula, Law, Orbit

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Enjoy our range of interesting gravity facts that help explain how gravity relates to both life on Earth and other objects in our solar system. Learn about important concepts such as acceleration, mass, tides and orbits as well as some useful formulas, strange trivia and other fun information relating to the topic of gravity.

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Quick revision with flash cards and games on Quizlet. You can even make your own set of questions!

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Check out this website! It has heaps of information and videos summarising gravity, mass and weight as well as telling us how much gravity there is on the other planets in our solar system. Worth a look. _Sarah_

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Gravity is a fundamental force of physics, one which we Earthlings tend to take for granted. You can't really blame us. Having evolved over the course of billions of years in Earth's environment, we are used to living with the pull of a steady 1 g (or 9.8 m/s ²). However, for those who have gone into space or set foot on the Moon, gravity is a very tenuous and precious thing.

Basically, gravity is dependent on mass, where all things - from stars, planets, and galaxies to light and sub-atomic particles - are attracted to one another. Depending on the size, mass and density of the object, the gravitational force it exerts varies. And when it comes to the planets of our solar system, which vary in size and mass, the strength of gravity on their surfaces varies considerably.

For example, Earth's gravity, as already noted, is equivalent to 9.80665 m/s ² (or 32.174 ft/s ²). This means that an object, if held above the ground and let go, will accelerate towards the surface at a speed of about 9.8 meters for every second of free fall. This is the standard for measuring gravity on other planets, which is also expressed as a single g.

In accordance with Isaac Newton's law of universal gravitation, the gravitational attraction between two bodies can be expressed mathematically as F = G (m ¹m ²/r ²) - where F is the force, m1 and m2 are the masses of the objects interacting, r is the distance between the centers of the masses and G is the gravitational constant (6.674×10⁻¹¹ N m ²/kg ² ).

Based on their sizes and masses, the gravity on another planet is often expressed in terms of g units as well as in terms of the rate of free-fall acceleration. So how exactly do the planets of our solar system stack up in terms of their gravity compared to Earth? Like this:
Gravity on Mercury:
With a mean radius of about 2,440 km and a mass of 3.30 × 1023 kg, Mercury is approximately 0.383 times the size of Earth and only 0.055 as massive. This makes Mercury the smallest and least massive planet in the solar system. However, thanks to its high density - a robust 5.427 g/cm3, which is just slightly lower than Earth's 5.514 g/cm ³ - Mercury has a surface gravity of 3.7 m/s ², which is the equivalent of 0.38 g.
Gravity on Venus:
Venus is similar to Earth in many ways, which is why it is often referred to as "Earth's twin". With a mean radius of 4.6023×10 ⁸ km ², a mass of 4.8675×10 ²⁴ kg, and a density of 5.243 g/cm ³, Venus is equivalent in size to 0.9499 Earths, 0.815 times as massive, and roughly 0.95 times as dense. Hence, it is no surprise why the gravity on Venus is very close to that of Earth's - 8.87 m/s ², or 0.904 g.
Gravity on the Moon:
This is one astronomical body where human beings have been able to test out the affects of diminished gravity in person. Calculations based on its mean radius (1737 km), mass (7.3477 x 10 ²² kg), and density (3.3464 g/cm ³), and the missions conducted by the Apollo astronauts, the surface gravity on the Moon has been measured to be 1.62 m/s ² , or 0.1654 g.
Gravity on Mars:
Mars is also similar to Earth in many key respects. However, when it comes to size, mass and density, Mars is comparatively small. In fact, its mean radius of 3.389 km is the equivalent of roughly 0.53 Earths, while its mass (6.4171×10 ²³ kg) is just 0.107 Earths. Its density, meanwhile, is about 0.71 of Earths, coming in at a relatively modest 3.93 g/cm ³. Because of this, Mars has 0.38 times the gravity of Earth, which works out to 3.711 m/s ².
Gravity on Jupiter:
Jupiter is the largest and most massive planet in the solar system. Its mean radius, at 69,911 ± 6 km, makes it 10.97 the times the size of Earth, while its mass (1.8986×10 ²⁷ kg) is the equivalent of 317.8 Earths. But being a gas giant, Jupiter is naturally less dense than Earth and other terrestrial planets, with a mean density of 1.326 g/cm ³.

Gravity anomalies on Mercury-mass concentrations (red) suggest subsurface structure and evolution. Credit: NASA/Goddard Space Flight Center/Johns Hopkins University/Carnegie Institution of Washington

What's more, being a gas giant, Jupiter does not have a true surface. If one were to stand on it, they would simply sink until they eventually arrived at its (theorized) solid core. As a result, Jupiter's surface gravity (which is defined as the force of gravity at its cloud tops), is 24.79 m/s, or 2.528 g.
Gravity on Saturn:
Like Jupiter, Saturn is a huge gas giant that is significantly larger and more massive than Earth, but far less dense. In short, its mean radius is 58232±6 km (9.13 Earths), its mass is 5.6846×10 ²⁶ kg (95.15 times as massive), and has a density of 0.687 g/cm ³. As a result, its surface gravity (again, measured from the top of its clouds) is just slightly more than Earth's, which is 10.44 m/s ² (or 1.065 g).

Mars Gravity Model 2011, showing variations of gravity accelerations over Mars's surface. Credit: geodesy.curtin.edu.au

Gravity on Uranus:
With a mean radius of 25,360 km and a mass of 8.68 × 10 ²⁵ kg, Uranus is approximately 4 times the size of Earth and 14.536 times as massive. However, as a gas giant, its density (1.27 g/cm ³) is significantly lower than Earth's. Hence, why its surface gravity (measured from its cloud tops) is slightly weaker than Earth's - 8.69 m/s ², or 0.886 g.
Gravity on Neptune:
With a mean radius of 24,622 ± 19 km and a mass of 1.0243×10 ²⁶ kg, Neptune is the fourth largest planet in the solar system. All told, it is 3.86 times the size of Earth and 17 times as massive. But, being a gas giant, it has a low density of 1.638 g/cm ³. All of this works out to a surface gravity of 11.15 m/s ² (or 1.14 g), which again is measured at Neptune's cloud tops.

All in all, gravity runs the gamut here in the solar system, ranging from 0.38 g on Mercury and Mars to a powerful 2.528 g atop Jupiter's clouds. And on the Moon, were astronauts have ventured, it is a very mild 0.1654 g, which allowed from some fun experiments in near-weightlessness!

Understanding the effect of zero-gravity on the human body has been essential to space travel, especially where long-duration missions in orbit and to the International Space Station have been concerned. In the coming decades, knowing how to simulate it will come in handy when we start sending astronauts on deep space missions.

And of course, knowing just how strong it is on other planets will be essential to manned missions (and perhaps even settlement) there. Given that humanity evolved in a 1 g environment, knowing how we will fare on planets that have only a fraction of the gravity could mean the difference between life and death.

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Gravity is a fundamental force of physics, one which we Earthlings tend to take for granted. You can't really blame us. Having evolved over the course of billions of years in Earth's environment, we are used to living with the pull of a steady 1 g (or 9.8 m/s2).

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We also made this table

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Quiz questions where you can discuss the answers and read how other people understand it.

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A short 6 question quiz about gravity, created for Digital Card 3 - Physical Science Grade 7.

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Test yourself with 10 multiple choice questions

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Kids take a quiz on Physics: Gravity. Practice science problems online test and questions for students and teachers.

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A little bit of history. _Amy_

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Education resources for schools teachers and students - ABC Education

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ABC Education has 4000+ educational games, videos and teaching resources for schools and students. Free Primary and Secondary resources covering history, science, English, maths and more

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This one is good too _Sarah_

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This gravity simulation is a sandbox on a grand scale. Put planets, stars, and asteroids in place, give them an initial push, and see where they go. Observe the conic sections that emerge from the simple rules of gravitational attraction.

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Fling planets and change physics in this gravity sandbox. Want to add 1000 planets? Go ahead. Curious about Lagrange Points? Make em. Hate the inverse square law? Change it.

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Have a play with this simulation, it's a bit fun! _Kate_

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This makes so much sense! _Kate_

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This is from NASA, I just thought it was cool! _Jack_

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NASA Live: Earth From Space - Nasa Live Stream  | ISS LIVE FEED : ISS Tracker + Live Chat

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Hey team, I've started a Google Doc for us to write notes about how we want to present our answer and what we want to include. Thanks, Sarah.

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A cool, real-life example of the effects of gravity and air resistance

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Felix Baumgartner's supersonic freefall from 128k' - Mission Highlights

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(also talks about Newton & Galileo)

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It dropped. It fell. Oh no. It dropped again. Is gravity getting you down? Introducing, Gravi-gone, 'cause you're a better you in space. Thanks, Gravi-gone.

JACK: Pfft, as if anybody's gonna fall for that.

MATT: Hi, yes, I'll have one Gravi-gone please, or 2, we'll just make it 4.

Unfortunately for Matt there is no escaping gravity, here on Earth anyway. Gravity is basically the super glue that holds everything down, in fact, it's the reason we even have a 'down'. But how does it actually work?

Well gravity is one of those things people have been wondering about for a really, really long time. There were lots of early theories and experiments to try to find out why things fall down. The guy who most of us think of as the grandfather of gravity is this guy, Sir Isaac Newton. He was an English mathematician, astronomer, theologian, author and physicist who came up with a theory about gravity almost 300 years ago. The story goes that Newton was sitting under a tree when an apple fell and hit him on the head.

JACK: Although some say that never actually happened, but whatever. But, whatever. The point is that whatever fell whether it was an apple or a banana or a fish led to Newton asking this question.

Why did the apple fall down onto the ground and not up into the sky, hmmm? He realised there must be an invisible force pulling the apple to the ground and he called that force gravity.

Now gravity works because every object that has mass is attracted, or naturally pulled towards, every other object that has mass. The force of that pull depends on how much mass an object has. An apple has a small mass whereas the Earth has a much, much larger mass so the apple falls towards the Earth. But the interesting thing about gravity is that it pulls everything towards the Earth at the same rate. That was discovered by a famous Italian guy called Galileo who dropped a heavy ball and a light ball from the top of the leaning tower of Pisa. Both were said to have fallen at the same speed.

JACK: Although that probably didn't happen either. But in any case, the moral of the story is that the two balls would fall at the same speed.

Of course, if you dropped a feather and say a hammer the feather would obviously take longer. That's because air pushes against the feather more than the hammer slowing it down as it falls. However, if you did the same experiment somewhere without an atmosphere, say on the moon, you'd find they both fall at the same rate. And here's proof from US astronaut David Scott in 1971.

DAVID SCOTT: How 'bout that.

Speaking of space, in order to get to the Moon, you have to fight very hard to break away from gravity. Which is why you need a really big rocket to say send a sports car into space. And why you'll need something more legit than a Gravi-gone.

MATT: I'm not sure if these are working. I need to buy some more.

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It dropped. It fell. Oh no. It dropped again. Is gravity getting you down? Introducing, Gravi-gone, 'cause you're a better you in space. Thanks, Gravi-gone. JACK: Pfft, as if anybody's gonna fall for that. MATT: Hi, yes, I'll have one Gravi-gone please, or 2, we'll just make it 4.

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Listen! A real-life astronaut explains what it's like in space. Gravity exists on all of the planets in space, but at different strengths, depending on their mass!

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Julie and her daughter, children's author and educator Emma Walton Hamilton, invite you into their library to read their favorite children's books. Every story comes to life with sound, music and activities. Authors, kids and other special guests chime in, too!

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Julie and her daughter, children's author and educator Emma Walton Hamilton, invite you into their library to read their favorite children's books. Every story comes to life with sound, music and activities. Authors, kids and other special guests chime in, too!

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I learn better when I read rather than watching a video, so thought this might help others too _Amy_

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I've started this mind map to summarise everything we are learning in this topic. Anyone can add to it and we can keep adding things as we learn more. Click the link to help. Thanks, Ben.

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Mind Map Free - Free Mind Mapping Software | MindMeister

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Watch! This helped me to make my award-winning parachute ;)

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Playtime with Parachutes | Physics for Kids

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This is like the experiment the teacher demonstrated at the beginning of Term, thought you might like to watch

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This scientific amusement is easily overlooked when you're thumbing through the pages of an old science book. How exciting can a few candles attached to a stick really be? Don't overlook one of true treasures of this book. The updated design makes this seesaw candle experiment a must-see part of your growing repertoire.

Experiment Materials

Pointed-tip scissors

2 small birthday candles

3 small paper clips

Ruler

Small plastic cup

Thumbtack

2 straws

Matches or lighter

Newspaper or surface you don't mind getting wax on

Experiment

The next question seems only logical: "What will happen when I light the second candle?" After about 15 seconds, the candles will start to move up and down in a seesaw-like motion. As time goes on, the swing of the straw gets greater and greater until eventually you get a full rotation. Some people will burst out in spontaneous applause while others will stare curiously at the contraption with a puzzled look on their face.

This demonstration is a great conversation starter, so it's important to give people enough time to ponder a solution and share their ideas before you share the science secret.

How Does It Work

Let's start by thinking about the seesaw you played on as a young kid. The seesaw is not just a playground toy-it is an example of a simple machine. In physics, simple machines are devices that make it easier to do work. A lever is an example of a simple machine. A lever is a straight rod or board that pivots on a stationary point called a pivot point, or fulcrum. Levers are often used to lift heavy loads. A seesaw, a shovel, a fishing pole, a pair of scissors, a baseball bat, and a wheelbarrow are all examples of levers.

What makes a playground seesaw fun is changing the masses (or the heavy loads!) on the ends of the board. However, unlike the Dripping Candle Seesaw, the playground toy moves up and down with some help from the pushing force of little legs. Since the candles don't have legs, there has to be another explanation.

As you might have guessed, part of the secret of the Dripping Candle Seesaw is actually in the name of the activity . . . dripping. The rotational action of the Candle Seesaw comes from the changing mass of the candles- potential energy that gets turned into rotational kinetic energy.

While it might have just sounded like a polite thing to do, putting down the newspaper to catch the wax drippings is the key to understanding how this works. Over time, you noticed that the candles began to drip wax, and in doing so they lost potential energy. If both candles dripped wax at exactly the same rate, there would be no movement-but this happens only when both candles are lit at exactly the same time. As the heavier candle in the seesaw moves downward, the angled flame causes the candle wax to melt faster and drip more. When the dripping candle loses enough mass, it also loses potential energy and moves upward (just like a seesaw). Now the candle on the other end moves downward, the angled flame melts the wax, which drops onto the paper, and the seesaw is set back into motion.

The careful observer is quick to point out that the height of the swing (otherwise known as the amplitude) increases with each cycle. Eventually the kinetic energy (or the energy of motion) is great enough to produce a full rotation, and with that comes cheers of excitement (or just a smirky grin followed by the utterance, "That's cool.").

Bob Becker first shared this demonstration with me at a conference for chemistry teachers at Old Dominion University in Norfolk, Virginia. Interestingly enough, Bob pointed out that the demonstration was first published in H. H. Windsor's book entitled The Boy Mechanic, Book 2: 1000 Things for Boys to Do, published by Popular Mechanics Press in 1915. While I first want to be quick to apologize for the book's title, I also want to point out that Bob's lesson is an important one to remember- the old is forever new.

Safety Information

WARNING! Since flames are involved, young scientists will need to round up some adult supervision before attempting this experiment.

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Candle Seesaw - SICK Science! | Science Experiments | Steve Spangler Science

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This scientific amusement is easily overlooked when you're thumbing through the pages of an old science book. How exciting can a few candles attached to a stick really be? Don't overlook one of true treasures of this book. The updated design makes this seesaw candle experiment a must-see part of your growing repertoire.

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Actual footage of a feather being dropped on the MOON!!

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Actual footage of a feather being dropped on the MOON!!

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This website has games and activities that work through each topic that we've done on forces and gravity. I found it really fun!

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Welcome to the most comprehensive online website for high school Science Years 7-10 covering the Australian Curriculum. This site is free to all Australian students and teachers and presents science in an engaging, guided inquiry-based approach to lift student interest and understanding.

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This is a good summary of what we learnt at the beginning of Term

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0:00 / 2:10•Watch full video

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This is what we did in class on Friday

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A little bit of revision on forces + GRAVITY!

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A little bit of revision on forces + GRAVITY!

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Really simple but i like it :)

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Defining Gravity: Crash Course Kids #4.1

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Galileo's Famous Gravity Experiment | Brian Cox | BBC Two

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Watch this video! It's a bit slow but helps me to remember the difference

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Watch this!

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If you've seen footage from the International Space Station or any of the space shuttle missions, you know that astronauts float around as they orbit the Earth. Why is that? Is it because the gravitational force on them is zero in space? (Or nearly zero?)

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Is anyone else having trouble understanding the difference between mass and weight? I'm still confused. Can someone help?
Thanks, JACK.

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I've been playing these games to help me understand balanced and unbalanced forces. You all should try it!

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Hi everyone, I always find these are good to work out what we know, what we need to work on and where we'd like to aim for our project. Feel free to add!