Gravity Variations Interactive (663.0K)
This Interactive is as much a game as it is an educational experience: you could call it the Isaac Newton Universal Gravitation Challenge. Place yourself on the Sun, the Moon, or any of the planets, and fire a cannonball with such precision that its trajectory lands it on a target. You’re trying to balance the force of gravity, which depends on the size and mass of the world on which you stand (or hover, for worlds with no solid surface). Now, choose your world, feel the force, and fire!

1		Here our mass and 4,000 miles radius give us a surface gravity, defined as 1 _, of 9.8 meters/second squared. Need a Hint?
			A)	g
			B)	G
			C)	H
			D)	h

Newton found the surface gravity of a planet depended both on its size and its mass. Here we will explore a variety of planetary gravity fields and the g forces involved which will help determine their atmopsheric compositions.

2		The Moon's 1/6 g sirface gravity explains the odd walk of astronauts in very bulky space suits while trying to explore the lunar surface in Apollo landing videos; if an astronaut weighed 180 pounds on Earth, on the Moon he would seem to weigh only: Need a Hint?
			A)	180 pounds.
			B)	1080 pounds.
			C)	30 pounds.
			D)	16 pounds.

Here we will explore a variety of planetary gravity fields and the g forces involved which will help determine their atmopsheric compositions. Let's find out why Mars' atmopshere is only about 1/100th as dense as ours.

3		Mars' surface gravity is determined by it having a mass about a tenth of the Earth's, and a radius about half of ours. How does its surface gravity, and ability to hold onto atmopsheric gases, compare to ours? Need a Hint?
			A)	1 g
			B)	.9 g
			C)	.4 g
			D)	.16 g

Here we will explore a variety of planetary gravity fields and the g forces involved which will help determine their atmopsheric compositions. First,who is most like us?

4		Of all the planets, which has the surface gravity most like our own? Need a Hint?
			A)	Mercury
			B)	Venus
			C)	Mars
			D)	Moon

Here we will explore a variety of planetary gravity fields and the g forces involved which will help determine their atmopsheric compositions, particularly for the huge jovians.

5		Which planet has the largest gravitational field, explaining its huge atmosphere; how does it compare to our own? Need a Hint?
			A)	Jupiter has about 2.6 times the gravitational pull of Earth.
			B)	Jupiter has over 300 times the gravity of us.
			C)	Saturn has about the same gravitational pull as Earth.
			D)	Neptune has about the same gravitational pull as Earth.