Starting from a known concentration students learn to use dilutions to determine the concentration of an unknown.
Dilution usually refers to a concentration of a material in a liquid and sometimes in a gas.
When we swallow a vitamin C tablet at breakfast we are diluting the vitamin C into our entire body. When we add bleach to a wash load or prepare a soap solution to wash our car, we are diluting a material to the proper concentration. In later lessons we will be diluting a concentrated sperm suspension to fertilize sea urchin eggs. They will need to understand dilution in order to be able to do these experiments in any kind of meaningful way. In this lesson an attempt has been made to relate dilution to the real world.