The 4th grade class at my kids' school was challenged
to design a science project that would be practical and locally applicable. My water girl's project earned her a second place
ribbon in the Environmental Science category at the regional science
fair.
Problem:
What everyday household materials can
be used to clean up a small oil spill in a local creek or pond?
Hypothesis:
I think that cotton balls will soak up
the oil from the spill the best (they will soak up the most oil).
Materials:
- 3 clear drinking glasses
- Water
- Vegetable oil
- 3 teaspoons cocoa powder
- Ruler
- Sharpie marker
- Spoon for mixing
- 1/4 cup cotton balls (4 cotton balls cut in half to make 8 pieces)
- 1/4 cup sponge (cut into 8 pieces)
- 1/4 cup shredded wheat (8 small squares of cereal)
- tongs
Procedure:
1.
Fill glasses with
cold tap water to 9 cm deep. Mark level on glass with a marker.
2.
Pour vegetable
oil into glasses until the level reaches 11 cm deep. Mark level on glass with a
marker.
3.
Add 1 teaspoon of
cocoa powder to each glass and mix well to imitate crude oil.
4.
Let solution
settle for 3 minutes.
5.
Carefully drop
1/4 cup of sorbent (sponge, cotton, shredded wheat) into each glass. Do not
submerge.
6.
Let glasses sit
for 12 hours.
7.
After 12 hours,
use tongs to remove sorbent materials from the glasses.
8.
Measure water
level and oil level to see how much oil and/or water was absorbed by each
sorbent.
Conclusions:
My hypothesis was not fully supported
by the data. Both the cotton and sponge sorbents soaked
up the same amount of oil, but the cotton soaked up more water than the sponge.
So, in real life, sponges would work better than cotton to clean up an oil
spill because cotton would be much heavier to remove from the water. The wheat fell apart and sank to the
bottom of the glass (could not be removed), so it would not work at all as a
sorbent in real life.
