Strength in Sand

What you need

• Piece of tissue 20 cm square
• Kitchen roll tube
• Sand
• A stick, e.g. dowel rod
• Rubber band

Instructions

1. Cover one end of the cardboard tube with the tissue paper. Hold it in place tightly with the rubber band
2. Poke through the tissue with the rod – it will tear. Start again with a new piece of tissue and fill the tube three-quarters full with sand. (Salt also works well.) Try poking the rod through again

Results and Explanation

The rod just won’t tear through the paper!

As you push the rod, the grains of sand are pushed away from it in all directions. The sand forms “arches” that push against the sides of the tube so that the entire force does not push down on the tissue.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.