Re: The News
Ciderman, I've been meaning to answer Jack's brilliant question!
If you want to show the boys, get all three of you plus mom or dad stretch out a flexible blanket and put a fairly ball in the middle of it. Explain to them that gravity is really not a force but a thing - the curvature of space/time which is represented by the bending of the blanket.
Next, put another smaller ball (say a tennis ball) in the blanket by rolling it in a wide arc near the top of the blanket and let them watch what happens. The ball also bends space/time because it has mass, but it ends up next to the first ball because the first ball has a lot of mass. Also try rolling the ball a few times so they can see the ball bending space/time by watching the ball moving from underneath the blanket.
Finally, put a large coin, flat on the blanket near the top. Is there curvature of the blanket (gravity)? There sure is! It just has so little mass that it doesn't slide towards the big ball. Put it very close, and it does! Gravity is dependent on mass and distance.
Hopefully that is a simple enough answer for a very sophisticated question!
I hope you all are saving for university funds. There are some very, very bright forum grandchildren!