Oceans and Salt Content (science activity)
"Seawater Float"

Teacher of Lesson: Teresa Moore
Grade Level: 2/3

Objectives:

Materials:

Procedures:

  1. Ask if the students have ever swum in salt water. Did they find that it was easier to float in a swimming pool or the salt water? We are going to try to find out if it is easier to float in one or the other. Have the students make a guess before starting the experiment.
  2. Have one member from each group fill 2 glasses half full of warm water. Have another student carefully slip an egg into each glass. (should sink to the bottom) Have the third student add 1tsp of salt at a time in one glass until the egg floats to the surface. Have the fourth student record the number of teaspoons it took to make the egg float.
  3. Have all the students draw the final results for the freshwater and saltwater eggs.
  4. Have the groups talk about what they learned from the experiment and write a few sentences describing a) what happened and b) what they learned on the back of their drawing.
  5. Talk about how salt would affect swimmers in the ocean as a class.

Evaluation:

  1. Do the students have a reasonable statement about what they learned, written on their papers? (collected)
  2. Did everyone take part in setting up and/or performing the experiment?
  3. Do the students have accurate drawings of their results on their papers? (collected)
  4. Did everyone get a turn in the group work? Did anyone dominate the discussions?

Extensions/ Reteaching Strategies:

I could throw in a hard boiled egg in a couple experiments. When the experiment fails, we can hypothesize what happened. See if the children can figure out the experimental flaw. It might show them the value in testing several times for validity. We could also try using a larger amount of water and see how much salt is needed to float the egg in that container. Why the difference in salt amount?
Return to the Desert/Ocean Habitat Home Page
Return to the YLP Units Page
Return to the YLP 1995-1996 Home Page