Saturday, May 19, 2012

Oil Spill Cleanup: Adventures in 4th Grade Science

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.


What everyday household materials can be used to clean up a small oil spill in a local creek or pond?


I think that cotton balls will soak up the oil from the spill the best (they will soak up the most oil).

  • 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

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.


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. 


Tuesday, May 15, 2012

How much water is on Earth?

Illustration by Jack Cook, Woods Hole Oceanographic Institution (©) Howard Perlman, USGS

This image from the USGS shows the size of a sphere that would contain all of Earth's water in comparison to the size of the Earth. 

Wow, right?

Double wow when you consider that the sphere includes "all the water in the oceans, seas, ice caps, lakes and rivers as well as groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant."

I shared this with my 4th grade water-loving-mermaid daughter, and she was distraught. "It looks like it might just disappear," she sighed.

I told her that the point of the picture is to illustrate how precious our water is. Treasure it, worship it, conserve it, but don't take it for granted. 

Who knows, I may just have the next Alexandra Cousteau in my midst ...