Step 1: Prepare the molasses solutions. Using a graduated cylinder or a measuring cup, prepare a 10% molasses solution, a 25% molasses solution, and a 50% solution. -To prepare the 10% solution, mix 2 ml of molasses with tap water until you get 20 ml of solution. Pour into a test tube and label test tube 10%. Place test tube in the empty beaker. -Rinse your measuring cup or graduated cylinder well.-To prepare the 25% solution, mix 5 ml of molasses with tap water until you get 20 ml of solution. Pour into a test tube and label test tube 25. Place test tube in empty beaker with the first test tube.-Rinse your measuring cup or graduated cylinder well and add 10 ml of molasses. Add another 10 ml of water to make 20 ml. Label test tube 50 and place in beaker. Step 2: Prepare the yeast solutions. With the group next to you, mix 7 grams of yeast into 200 ml of warm tap water. You will be using this same 200 ml yeast solution between both groups. -Stir the yeast into the warm tap water until it is evenly suspended in the solution. -Add 25 ml of the yeast solution to your 10% solution.-With your thumb over the top of the tube, shake each tube gently for 20-30 seconds.-Immediately and carefully, place a LARGE test tube over the top of the test tubes containing the molasses-yeast solution and invert the tubes. -Repeat with the 25% molasses test tube and 50% molasses solution. -Place each tube in the rack in the warm water bath. As the yeast eats the molasses, they will produce CO2 (just like you do when you breathe out). The yeast will also grow and reproduce. The amount of CO2 produced is an indirect way to measure the population growth of your yeast populations.

1. What differences do you think you will see between the 3 molasses solution? Write your expectations for what will happen below:

2. Why do you think this will happen? Write a justification for why you think what you wrote in #1 will happen:

Step 3: Record your data. Using aruler, record the space, in centimeters, created at the top of the test tube using the time intervals listed on the chart on the back of this page. Millimeters of CO2 created10% solution25% solution50% solution Millimeters of CO2 created10% solution25% solution50% solution 1 minute12 minutes2 minutes15 minutes3 minutes17 minutes4 minutes20 minutes5 minutes22 minutes6 minutes25 minutes7 minutes27 minutes8 minutes30 minutes9 minutes__ minutes(end of class)10 minutes3. Which test tube created the most from CO2?

4. Why do you think this occurred?

5. Graph the rate of each test tube’s CO2 production below (use a separate line for each test tube; note which is which) DELETE THIS GRAPH ANDUSE EXCEL OR GOOGLE SHEETStimemm of CO2

6. How do you think shaking the tubes affected the growth of the yeast and the production of CO2? Explain:

7. The solutions of molasses were models of carrying capacities of a habitat. Explain how the availability of molasses to yeast in a test tube is similar to availability of resources in a habitat:

8. What happened to the yeast population when we increased the amount of molasses in the test tube? (Use carrying capacity in your answer.)

9. How might increasing the amount of food in a habitat affect the population of wildlife in that habitat? (Use carrying capacity in your answer)

10. Could doubling the carrying capacity of a habitat have any negative effects to that habitat and the wildlife that live within it? Explain: