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Teach Matter and Energy
with Gravity Simulator

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Matter and Energy

What is matter and what is energy?

Teacher Resources

This lesson is meant as an introduction to Gravity Simulator. This simple, accessible simulator allows your students to observe how planetary orbits and other gravitational phenomena work.

  • Theory: This lesson explores the differences between matter and energy.
  • Play: Students learn how to play Gravity Simulator with simple tasks and assignments.
  • Share & Discuss: These slides focus on the differences between matter and energy and the experience of playing Gravity Simulator.


  • Energy is defined as the capacity of a physical system to perform work.
  • When a force acts upon an object to cause a displacement of the object, it is said that work was done upon the object. (source)
  • There are many kinds of energy, such as heat, potential, kinetic and nuclear.

Midsummer Pyre.

Teacher Resources

In the picture, you can see fire, which is a chemical reaction that produces energy, even though fire by itself is not energy.

Use your own sources and the ones below to teach the concept of energy to your students:



Image Source: Midsummer Pyre, Wikimedia Commons


  • Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space. If you are new to the idea of mass, it is the amount of stuff in an object. (source)
  • There are four basic states of matter: gas (example: steam), liquid (water), solid (ice) and plasma (lightning, neon lights, plasma TVs).

States of matter.

Teacher Resources

Matter has four basic forms - gas, liquid, solid and plasma. There are other states as well such as the Bose-Einstein condensate (only occurs in extreme cold) but the four basic forms are all around us in our everyday lives.

The picture demonstrates that the difference between different states depends on how closely the particles of the matter are together, so liquid has more volume than the matter as a solid because the particles are not as close to each other. (Additional note: a well-known exception to this is water and ice, because ice has particles that are not as close as in water, and thus ice has more volume)

Use your own sources and the ones below to teach the concept of matter to your students:



Image Source: States of Matter, Wikimedia Commons

Gravity Simulator

  • A scientifically accurate simulator that depicts objects in space and their gravity and kinetic energy
  • You can add objects, change their mass and velocity and name them
  • The simulator contains ready-to-go simulations, such as Sun, Earth and Moon.

Teacher Resources

This is just a simple introduction for the students so they know what to expect from the simulator. It’s a good idea to try out the simulator on your own before this lesson, so you can help the students if they are having trouble.


Main Menu

Learn how Gravity Simulator works!

Gravity Simulator main screen.

After you’ve launched Gravity Simulator, this is the main screen. Your students should select the load from code option, but below are descriptions for each option for your convenience.

  • Build: Start the simulation with nothing in it. Useful for experiments when you want to work on something specific.
  • Load from code: Loads up a ready-to-go simulation. Quickly gets you started and is the easiest way to learn how the simulator works.
  • Toggle fullscreen: This lets you play the simulator in a window or in fullscreen mode. This is a purely personal preference and has no effect on the simulation itself.
  • Exit the universe: Stop playing and close the program.

Loading from Code

Saving and Loading.

Have each student select the Sun Earth and Moon scenario by clicking the name and then clicking load.

Lesson Goal #1

Earth, Sun and Moon.

Below are instructions for how to add names to objects in the game (these instructions assume you’ve loaded the Sun Earth and Moon scenario). This can make the simulation more comprehensible. Additionally, it also teaches how several tools of the simulator work: have each student complete each step according to your instructions.

To add names to objects, you have to do the following:

  1. Pause the game. Select the pause symbol in the top left corner of the screen so it is easier to select objects.
  2. Make sure you have the pointer selected. In the top right corner, you can select the simulator’s tools. Select the first tool - the pointer. This allows you to select objects in the simulation.
  3. Select an object. If you do this correctly, a dialog box will open in the top right corner of the screen (pictured).
  4. Select the “name” slot by clicking on it. This slot is found in the dialog box, at the top.
  5. Type in the name and press enter. If you do this correctly, the name will show up on the main screen (pictured).

If students are having trouble, be sure to help them out. Move on to the next task only after everyone has successfully added names to their objects.

Lesson Goal #2

Building your own orbit.

This task is more difficult than the previous one, but there is no hurry. As long as you reserve 5-10 minutes for the last two slides - which contain discussion topics and tasks - feel free to let the students get acquainted with the simulator for the rest of the time.

To build your own orbit, you need to follow a few steps.

  1. First, you need an empty workspace. The quickest way to do this is by clicking the X symbol in the top left corner of the screen when you are already in the simulator.
  2. Now everyone should have an empty workspace. First, you need to add a star that is not affected by gravity: this will allow you to build orbits around it (in real life stars are affected by gravity as well but the simulator includes the option to have stars immune to gravity as celestial bodies are placed instantly rather than formed over time as in real life). To add a star immune to gravity, select the second symbol in the top right corner of the screen (the yellow ball with the red orbit symbol over it). Click anywhere to place the star.
  3. Now you need something to orbit the star. Select the planet tool (the fourth symbol, the blue ball) in order to add a planet. Make sure to add only a single planet, and try to add it somewhere where it isn’t too far away and not too close. If it is too far or close, you can simply delete the planet and try again. To delete objects, select it with the pointer tool and either press delete on your keyboard or delete in the dialog box.
  4. Now that you have a planet, it will start to be attracted by the star (provided it is close enough). Now you have two options for making the planet orbit the star: a precise but difficult method and an imprecise but easy method. Both are outlined below.

Precise but difficult: This involves changing the values heading and speed in the dialog box as you have the planet selected. With sufficient speed and the right heading, the planet will start to orbit the star. Only experimentation will make you understand how these values work.

Imprecise but easy: This involves simply using the graphic user interface. First, you have to make sure you have the right trail settings: in the bottom right corner, select the second option from the top, and make sure that the options trails on and ellipses instead of trails are enabled. Second, you have to let the planet gather speed: you know this is happening as it starts to move towards the star. Then, before the planet hits the star, pause the simulation by pressing the pause button in the top left corner. Now, select the planet and drag it until its predicted orbit completely avoids the star. Finally, resume the simulation by pressing the pause button again.

Tasks for students who are ready: Some students might be finished sooner than others. In that case, they should keep on playing the simulator on their own, trying out the different features and seeing what you can do in the program.

Share & Discuss

Share & Discuss

  • What was fun about the simulator?
  • Did you learn something new about gravity? What was it?
  • Was there something you wanted to do in the simulator but didn’t know how to? What was it?

Tasks after Playing

What is the definition of energy?

Show Notes

Energy is defined as the capacity of a physical system to perform work.

Is fire energy?

Show Notes

No. Fire is a chemical reaction which by itself is not energy, but transforms some of the energy in the chemical bonds of matter into heat energy.

Can you name at least two types of energy?

Show Notes

For example: kinetic, heat, potential, nuclear.

What are the four main types of matter? Can you give an example of each type?

Show Notes

Plasma, gas, liquid, solid. Respectively: lightning, steam, water, ice (all but lightning are different forms of the same type of matter in this case).