While you’re waiting for the lactase solution to cool, read the directions on the test strips. The test strips in the Edmentum lab kit will react to glucose within a few seconds. If you use different strips, the reaction time may vary. Now follow these steps to test the solutions. Record your data in the answer space. Milk and water solution: Fill the first test tube one fourth full of milk. Fill the small graduated cylinder with water and gently add it to the milk in the test tube until the test tube is half full. Use the stirrer to thoroughly mix the solution. Then insert the test strip for 10 to 20 seconds. Look at the test strip, and record whether it changed color. Wash the stirrer.
Milk and lactase enzyme solution: Fill the second test tube one fourth with milk and one fourth with the lactase solution. Use the stirrer to thoroughly mix the solution. Insert the test strip for 10 to 20 seconds, and record whether it changed color. Wash the stirrer.
Milk and heated lactase enzyme solution: Fill the third test tube with one fourth milk and one fourth of the heated lactase solution. Use the stirrer to mix the solution. Insert the test strip for 10 to 20 seconds, and record whether it changed color.
Note: Keep the lactase and heated lactase solutions for the next part of the experiment.

Wash the “milk” beaker, the test tubes, and the stirrer. If you used paper cups as an alternative, throw them away.