Most were from fifth and sixth graders. You can listen to thunder after lightening and tell how close you came to getting hit. If you don't hear it you got hit, so never mind. The law of gravity says no fair jumping up without coming back down. Rainbows are just to look at, not to really understand.
Most books now say our sun is a star.
But it still knows how to change back into a sun in the daytime. A vibration is a motion that cannot make up its mind which way it wants to go. Vacuums are nothings. We only mention them to let them know we know they're there. There is a tremendous weight pushing down on the center of the Earth because of so much population stomping around up here these days.