Now repeat the procedure with test tubes 2 and 3. Be sure you record the exact time you added the yeast to each tube. 8- Relax and wait until each tube's color changes from blue to white. Record this time to the nearest minute. 5- Shake one of the test tubes that turned white.
Air is added naturally to rivers when water goes through rapids and over falls.
Name the part of the experiment that represents microorganisms. 9- Name the part of the experiment that represents waste. Some bacteria, given ample food and water, can multiply every 20 minutes. 1- You may use fresh or powdered milk. Two liters of milk are enough for five classes.