Absorption
Absorption is when a material soaks up a liquid or gas and holds it inside.
A dry sponge sits next to a bowl of water. You press the sponge into the bowl, and it pulls the water in. The water fills the tiny holes inside the sponge and stays there. Lift the sponge out, and it holds the water inside its body.
Explaining absorption by grade level
Think about cleaning up an oil spill with a pad. The pad soaks up the oil like a sponge soaks up water. The oil goes into tiny holes inside the pad. Some pads soak up more oil than others.
Projects that explore absorption
When a material soaks up a liquid and holds it inside, that's absorption in action. In this experiment, you pour equal amounts of oil, gasoline, and antifreeze through sand and clay, then measure how much each soil absorbs in 60 seconds. The results are striking: clay soaked up 220 milliliters of oil out of 250, while sand absorbed only 126 milliliters.
Polypropylene pads soak up oil from water during spill cleanup — a direct application of absorption. The question here is whether adding detergent to the water changes how well the pads hold oil inside. If detergent affects how much oil the pads absorb, it reveals whether detergent helps or blocks absorption.