MATERIALS: a horseshoe magnet for each student a big piece of cardboard and many paper clips for a class demonstration a glass of water, a paper clip, a wooden or plastic ruler, enough books to make two even stacks and a piece of cardboard with a maze drawn 
(a glass of water, a paper clip, a wooden or plastic ruler, enough books to make two even stacks and a piece of cardboard with a maze; drawn; )
a glass of water, a paper clip, a wooden or plastic ruler, enough books to make two even stacks and a piece of cardboard with a maze
drawn