Paper Engineering
   Lay a sheet of notebook paper across two books, and load coins onto the paper. The paper sags. Now bend and place the paper as shown. Will it support the coins?
 How it Works
 Shape can make a big difference. The bent paper can hold the weight of the coins. It's the same with steel. If we use flat sheets of steel to support a heavy weight, they do not work well. If we bend the steel into the right shapes, it will hold great weight.
 Look at the picture. If we bend two pieces of steel as we bent the paper and fit them back to back, we create a special design called an I-beam. Steel I-beams are the basic supports used in building skyscrapers.
   Soure: highlightskids.com
  
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