Osmotic Strength

Set up test tubes with about a half an inch of each of the following solutions:


100% seawater


9 parts seawater and 1 part distilled water


8 parts seawater and 2 parts distilled water


7 parts seawater and 3 part distilled water


6 parts seawater and 4 part distilled water


Equal parts seawater and distilled water

  1. Add one drop of concentrated eggs to each.
  2. Swirl and let sit for one minute.
  3. Add one drop of diluted sperm suspension and swirl briefly.
  4. Wait 5 minutes.
  5. Score eggs for fertilization. If time permits can also score for later development [Next period see if divided. Next day see if there are swimming blastula.]