Students design, build and test model roller coasters using foam tubing. The design process integrates energy concepts as they test and evaluate designs that address the task as an engineer would. The goal is for students to understand the basics of engineering design associated with kinetic and potential energy to build an optimal roller coaster. The marble starts with potential energy that is converted to kinetic energy as it moves along the track. The diameter of the loops that the marble traverses without falling out depends on the kinetic energy obtained by the marble.

So, if gravity pulls everything down, then why don't things on the bottom of the Earth get pulled down into space? In this episode of Crash Course Kids, Sabrina talks about gravity and explains that when we talk about gravity pulling things down, what we really mean is gravity is pulling things TOWARD the Earth. Really, it's all about attraction.

Learn about conservation of energy with a skater dude! Build tracks, ramps and jumps for the skater and view the kinetic energy, potential energy and friction as he moves. You can also take the skater to different planets or even space!

Visualize the gravitational force that two objects exert on each other. Change properties of the objects in order to see how it changes the gravity force.

Move the sun, earth, moon and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it!

Do you know how many people have been to the moon? Only 12! Part of the reason it's so few is because of how difficult it is to escape Earth and get into space in the first place. In this episode of Crash Course Kids, Sabrina talks about gravity, escape velocity, and how gravity works between two objects.

Can you avoid the boulder field and land safely, just before your fuel runs out, as Neil Armstrong did in 1969? Our version of this classic video game accurately simulates the real motion of the lunar lander with the correct mass, thrust, fuel consumption rate, and lunar gravity. The real lunar lander is very hard to control.

Build your own system of heavenly bodies and watch the gravitational ballet. With this orbit simulator, you can set initial positions, velocities, and masses of 2, 3, or 4 bodies, and then see them orbit each other.

Do you want to be an astronaut? Would you like to someday walk on the moon? Well, you better learn a little about gravity so you can escape from Earth and head into space. In this video, Sabrina chats with us about what it takes to get to the moon!