In this science experiment, kids get to discover which paper towel brand is the most absorbent. Begin by lining up three to five paper towel rolls on a table and giving them alpha-labels, such as A, B and C. Tell kids to touch the paper towels and make a guess -- or hypothesis -- about which paper towel will be the most absorbent. For the experiment, pour 200 ml of water or juice into individual bowls. Soak one paper towel sheet from each of the paper towel brands into the bowls, and see which paper towel sheet is able to absorb the most liquid. Have kids assign the paper towel brands from best to worst and check their conclusions against their hypotheses.
The strongest paper towel project tests paper towels for strength, rather than absorbency. Here, the same three to five paper towel brands are lined up, and kids guess the brand that they think is the strongest. For the test, take one paper towel sheet and place one cup of grapes on top of it. Scoop the grapes and paper towel up by holding onto the corners of the paper towel, and run the entire thing under water from the sink faucet for 20 seconds. The object of the project is to see which paper towel brand lasts the longest under the pressure of the water and the weight of the grapes. For a variation on this project, use coins instead of grapes.
The most soluble color project is one that tests which colors of the same type of marker are the most soluble in water. To conduct the experiment, tape a few strips of paper towel to a pencil so that the strips dangle down. Use a marker to make a dot on the end of the paper towel strips -- each strip should have a different colored marker dot. Then, place the pencil and strips over a glass cup and fill the cup with water until the tips of the paper towel touch the surface of the water. Watch as the marker dots travel and spread around the paper towel from the contact with the water, and determine which color is the most soluble.
The paper towel rip is another strength project where kids decide which paper towel withstands being ripped the longest. For the project, have two kids hold one paper towel sheet between them, firmly grasped. The third person in the project drips one drop of water from an eyedropper onto the sheet. More drops are added until the paper towel is weakened enough by the water to rip. Count the number of drops that it takes to make the paper towels rip, and try the experiment with different brands of paper towels, to see which one is the strongest.