The Leaning Tower of Pisa was originally designed the bell tower for Pisa's cathedral. Construction began in 1173 but halted after the completion of the third floor. Built on a clay mixture, the ground began to shift and the tower tilted. Construction did not resume for almost 100 years, when workers added four additional floors and a bell tower. A simple model of the tower will demonstrate how the addition of counterweights has helped stabilise the structure.
Open the oatmeal container and pour 1 cup of sand inside. Close the container, but do not seal. Set the container on the centre of the flat side of the semicircle wooden block. It should balance easily. Move the oatmeal container slightly toward one end of the block until it tilts slightly. Mark this spot with a pencil. If the block does not tilt, add another 1/2 cup of sand to the container and try again. Glue the container lid down and set aside to dry.
Wrap the cream-coloured paper around the oatmeal box and cut to fit so the paper wraps easily around with 1/2-inch overlap. Repeat with the small tuna can. Follow the pattern and design in the picture of the tower, draw a copy of the bottom seven floors on the large piece of cream-coloured paper, then draw the bell tower on the small piece.
Wrap the small paper around the tuna can and glue into place. Wrap the large paper around the oatmeal can and glue into place. Glue the tuna can in the centre of the top of the oatmeal container. Set it aside to dry.
Place the oatmeal container on the wooden block in the spot previously marked. Verify that the tower still tips---it should tip a bit farther than before. Glue the tower into place. Place the penny counterweights on the flat surface of the wooden block so that the tower does not tilt as far.