The ability of matter to soak up a liquid is called absorbency. A great way to examine the concept of absorbency is to have your kiddos take turns placing various items in a cup of water and determine whether they absorb any of the liquid.

The students at All About Children childcare center had lots of fun with this simple lab and used the following materials...

Materials

plastic cup

water

cotton ball

sponges

piece of cheese cloth

piece of T-shirt

ear plug

stopwatch

Completing the Lab

1. Have students select an object from the testing pile, inviting them to hypothesize whether or not it will soak up any of the water.
2. Have them place the object in the water for 20 seconds.
3. At the end of the 20 seconds, invite them to pull the item out of the water and gently squeeze it (making sure to keep the object over top of the cup!).
4. Discuss the results - how they compared to the hypothesis - and complete the same process until all of the objects have been tested.

Extensions

This lab was done with younger children. For older children, it might be fun to compare the various items to determine which is most/least absorbent. To do this, you'll need three extra items - a beaker, a graduated cylinder, and a funnel.

Here's a revised procedure...

1. Fill the beaker up with exactly 200 ml of water.
2. Add the first item to the water. As this is done, start the stopwatch.
3. After 20 seconds, remove the object from the beaker and, using the funnel, squeeze as much water as you can in to the graduated cylinder. Record the volume of water squeezed from the item.
4. Repeat until all of the items have been tested and record the results in your data table.
5. Compare the results and determine which object is most/least absorbent!