Sorry it took me so long to respond to your question. There are many things which effect the strength of paper towels. Paper is made by grinding up wood and saw dust. It is combined with water to form a pulp. The pulp is then pressed and allowed to dry. The strength of the paper will vary depending on the length of the fibers which make up the sheets and the types of wood used in making the paper. Paper towels are "softer" and lighter then sheets of writing paper because they contain far fewer fibers per square inch. Writing paper is stronger and denser, but less absorbent than paper towels. Some rolls of paper towels or toilet paper "seem" softer than others only because the manufacturer rolls the paper very loosely around the center tube. When comparing prices this is an important consideration. A smart shopper always checks the total square footage and number of ply (1-ply, 2-ply, meaning one or two sheets thick).

In conducting your experiments, it is extremely important that you concentrate on the reproducibility of your procedures. That means that all of your tests must be as similar as possible. The sheets must be the same length. Have you ever walked around in snow shoes? If you step in the snow in sneakers, your foot will go right through. Snow shoes are designed to spread your weight across a much larger area. This is how they allow people to walk on top of the snow. The length of the towels, the placement of weights on them, the way in which you hold the towels, and the manner in which the water is distributed across the towels can all effect the way force (or weight) is distributed across the paper towels.

Good luck,

Marc Breen