text: what should i do to makemy sis's project on solar system look great ???????   one of the most exciting excercises i ever did as a kid was to make a scale model of the solar system. most of the pictures in my books made the distance between planets seem small and easy to travel. museums were no help either. the models they displayed usually had the sizes of the planets to scale, but the distances between them were a completly different scale, giving the impression of a rather close-knit family.   i made my first scale model on a roll of teletype paper tape (anyone remember that stuff?) on this 1-inch tape, my sun was the size of the tape - 1 inch in diameter. it all started out well. mercury was only about 3-1/2 feet from the sun and earth was almost 9 feet from the sun. what i didn't bargain for was that pluto was 354 feet down the tape! i used up almost the entire roll.   i also calculated the sizes that i should make the dots that represented the planets. i found that even the largest planet, jupiter, should have a spot size smaller than 1/8 inch. the other planets, especially the small rocky inner planets, would be virtually invisible dust spots.   needless to say, this was an eye-opening experience. this one excercise taught me the real meaning of the word "space." it sure made me feel insignificant looking at the scale of the solar system - never mind the rest of the universe!