Science Projects Index
Take a paper box such as a shoebox. Put a weighing stone of around a quarter kilo in the box and using tapes and gum fix it on one side of the inside of the box. Now start pushing the box to the edge of the table on which it is placed. You will find that you are able to push the box to more than three-quarter of the box if the weight is in the back.
Size and Force
Take two sheets of newspaper and spread it on a table. Now place a foot ruler under the sheets in such a way that two third of the ruler is under the sheet and one third out side the table. Now you take a hammer and hit the ruler on its outside edge and see what happens.