Goals:
Resources:
Aubrecht, D.J., Barefoot, A.F., Blume, S.C., Feather, R.M. and Ortelo, E.P. (1990). Science Connections. Columbus: Merrill Publishing Company. 309
Materials:
The following will be distributed per group. Four plastic vials, five small jars, red food coloring, blue food coloring, green food coloring, yellow food coloring, tap water, salt, ice water, hot tap water, droppers, pencil, and labels for jars.
Time:
90 minutes
Procedure:
1. Display currents of the ocean on an overhead projector. Explain surface currents and density currents.
2. Assign groups to a table with materials and inform the groups that this experiment is on density currents and variables that affect ocean currents.
3. The groups will label their jars one through five.
4. The four vials need to be filled half to three-quarters full with water, as well as jar 1. fill jar 2 with hot water and add drops of red food coloring, fill jar 3 with ice water and add drops of blue food coloring, fill jar 4 with tap water, add salt, and add drops of green food coloring, and fill jar 5 with tap water and add drops of yellow food coloring.
5. Before beginning the experiment each group will hypothesize what will happen when each of these liquids are placed into the tap water in the vials.
6. Take a dropper, extract liquid from jar 2, and squeeze the dropper into the first vial. Students will record their observations. Repeat the procedure with jars 3-5.
7. Inform groups about how temperature and salinity affect ocean currents and about how warm water is less dense than cold water. Also, explain that hot water with a greater salt content is denser than water with less salt content.
8. Compare hypothesis with outcomes
Assessment:
1. Comprehension of formation of currents, types of ocean currents, and variables that affect ocean currents from observations and discussion with teacher during group experiment.
2. Success in hypothesizing the outcomes, and recording the outcomes of the experiment. Comparing the hypotheses with the outcomes of the experiment. Criteria for Success = Completion and positive feedback from peer and self-evaluations. (Refer to self and group evaluation rubrics)
Curricular Strands and Major Concepts:
1. Science- hypothesizing and recording results on how variables such as salinity, temperature, and density affect ocean currents.
2. Language Arts- predicting thoughts and writing these hypotheses in paragraph form.
3. Social Studies- location of various types of currents.
Discussion Topics before and after Experiments:
Possible Extensions:
1. Conduct other experiments on how objects may float on different densities of water.
2. Researching the differences of lake freshwater compared to ocean saltwater.