A rather simple experiment for elementary level science, students fill a large jar with about half a gallon of distilled water. They then pour about a quart of cooking oil into the jar and allow the ingredients to settle, gently moving the jar to simulate waves once the oil has completely separated from the water. For added clarity, students can add a rock and small floating bath toy to the jar, representing marine life that lives on the ocean floor and surface. Students should take note of how oil separates from water and settles on the surface, keeping animals from rising up to the surface or moving onto the ocean floor. Students can also create hypotheses about how this contamination and division might impact ocean life.
Although a number of factors, such as wind and temperature, impact ocean currents, salinity determines many of the water exchanges in the open ocean. In order to simulate this dynamic in a lab, students mix one jar of salt water (fully saturating the water with as much salt as will dissolve in the jar) and add blue food coloring to the mix. A second, larger jar is filled with distilled ("fresh") water and mixed with red food coloring. When the blue jar of salted water is gently poured into the jar of fresh water, students will be able to observe the denser blue water sinking to the bottom, while the red water gathers at the top and the two begin to mix slowly as the salt dissolves equally into both types of water. Students should ask themselves about the impact of salinity and density on ocean currents and how water mixes and moves in the open ocean.
Simulating a solar desalination plant, students place an empty glass inside a larger bucket containing salt water, cover the top of the bucket (with the glass inside) with cellophane wrap and place a small weight in the center of the cellophane wrap over the glass. After a few days of sitting in the sun, water will begin to evaporate from the bucket, condense on the lid, roll down along the angle of the wrap made by the weight and drop into the glass. After several days, the glass should be full of desalinated water and students will find salt residue along the base of the bucket. This experimental desalination plant should teach students about ocean salinity, evaporation and the importance of fresh water for human consumption.
An experiment for advanced students, simulating ocean acidity is a valuable experiment for understanding the impacts of ocean acidification, a possible threat of global climate change. Students obtain mussel shells from a local fish monger and place a few in a control jar of untreated water and a second set of shells in a jar with water and vinegar. Students can also use pH paper to test the acidity of each jar and make several jars with different amounts of vinegar (and different pH values) in order to test different levels of acidity. By carefully documenting the changes in the mussel shells in a logbook, students can hypothesize about the potential effects of ocean acidification on marine food chains and organisms. They can also gain experience in useful lab practices like documentation and pH readings.