Walk-In Take out notebook, folder, pencil box. Take out pink lab sheet and a pencil. READ your sheet over quietly.

Some changes to your sheet… Section 1 – Don’t put corn syrup into tray. Just put three squirts directly into the test-tube, then add Benedict’s, then heat. Section 6 – Don’t put DW into tray. Just put three squirts directly into the test-tube, then add Benedict’s, then heat. All others: Mix the food with 2-3 squirts of DW. Mix with a clean pipette. Put most into of it into the test-tube. Leave a little in the tray to test for starch later.

Testing for Sugar Add 10 drops of Benedict’s solution. Mix. Heat for 1 minute. Remember which test tube is yours! Observe color change, if any. Record in chart.

Sharing the Work A and B – Test foods #1, 2 and 3. C and D – Test foods #4, 5 and 6. While one pair is mixing and heating, the other pair can be cleaning test-tubes. Put test-tubes with solids into the bin on the round table.

Testing for Starch At the end, add 2 drops of Lugol’s solution to what is left in each tray section. If there is starch, it will turn dark blue/black. Record in chart on back.

Clean-Up Wash each test-tube as you are done with it. Put test-tubes with solids into the bin on demo table. Wash out the pipettes at the washing station, then put back in bin. Answer the questions on the back when done.

Exploring Carbohydrates: Testing for Sugars and Starch Human Body Systems Lab

Lab Goal We will learn about which foods contain sugar and starch, since these are some of the nutrients our bodies break down and absorb during digestion. We will test 5 foods with two solutions, to see if they change color. If they do, it means that sugar and/or starch are present.

Lab Sheet – Will be collected at end of class on Wednesday Read the top section. Be ready to fill in certain sections today as we go over them.

Carbohydrates “Carbs” are one of the 3 basic food types – carbohydrates, protein, and fat. They are a major source of energy for the body Sugar and starch are both carbohydrates.

General Procedure You will mix a food with water, in each of the six tray sections. use a pipette to add some of the FOOD SOLUTION to a test tube. Add Benedict’s solution to the test tube Heat the test tube for 1 minute, then check for a color change.

Indicators An indicator is a substance that changes in some way to indicate or show the presence of another substance. Benedict’s Solution – when added to another solution and heated will change color from blue to light green to red in the presence of increasing concentrations of sugar. Lugol’s Solution – when added to a solution or food, it will change color to indicate the presence of starch. Benedict’s Solution will irritate eyes and skin. Do not let it touch your skin. Lugol’s is poisonous.

Hot Water Bath A hot water bath is a convenient way to heat a substance when you want to maintain a constant temperature. It is used in science class for safety reasons and also because a flame might break the test tube. It is still very hot so please be careful when working with the water bath.

Lab Materials One person will bring the group’s lab-bin to the table. Everyone can look at the small tray with sections, and examine the materials we will use. CAREFUL WITH THE GLASS TEST-TUBES. Look at your lab sheet. Discuss how you will prepare each tray section.

Let’s model the procedure! We will just practice (WITH NO MATERIALS!) how to put the clamp on a test tube, and to place it in a hot pot. Check out the washing station on the round table for cleaning out test-tubes. 1. soap + water 2. plain water to rinse.

General Procedure 1. Mix solutions in your tray, using the stuff in #2, 3, 4, and 5 and adding the amount of water it says (do 2 to 3 squirts of DW). For section #1 – just put corn syrup solution into test tube. For section #6 – just put DW into test tube. 2. Use your pipette to add the liquid to a test tube, then add the amount of Benedict solution it says to. 3. Heat the test tube for 1 minute. Afterward, check if there was a color change.

Procedure, continued 4. Let the test tube cool. While the next test tube is heating, you can pour out the old one at the sink, then wash it at the washing station. 5. If test-tube has a solid in it, just put it in the bin on the demo table.

When done cleaning up… All supplies should be returned to the demo table baskets. Your group’s lab bin should be neatly organized like this:

Lab Safety Wear safety goggles when working with the chemicals or hot water bath. Do not hold the test tube clamp while in the hot water bath Do not let any Benedict’s Solution or Lugol’s Solution touch your skin. Do not touch the test tubes When finished, place the test tubes in the bin by the sink. If any solution comes in contact with your eyes notify me immediately and rinse eyes with water Report any spills immediately.

Lab Write Up Problem: Which foods contain sugar? Hypothesis: If I test for sugar, then the following foods: _____________________ _______________________ will test positive for sugar because ___________ ____________________________________ Foods we are testing: corn syrup, potato buds, marshmallow, cornstarch, egg whites

Variables Independent Variable: type of food Dependent Variable: color in test tube to show if sugar or starch is present

Procedure Fill each test tube with the CORRECT AMOUNT of the food you are testing, Benedict’s Solution, and Distilled Water. Attach clamp to test tube Using clamp as a handle, place test tube in water bath. Do not remove clamp. Let sit for 1 minute. Using clamp, remove test tube from water bath and place back in test tube rack. Observe color of liquid. Record color of liquid on your data chart. Use a + to indicate sugar is present on your data chart

Make sure your Problem, Hypothesis, and Variables are completed before Testing For Sugars Make sure your Problem, Hypothesis, and Variables are completed before starting the tests.

Foods we will be testing Corn syrup Marshmallow Potato Buds Egg White Powder Cornstarch Distilled water – our control group – water that has most of impurities removed

Data Chart – Testing for Sugar Food Tested Color + sugar - no sugar Distilled water Corn Syrup Potato Buds Marshmallow Corn Starch Egg Whites

Amounts for each test tube 1.Corn syrup: 20 drops + 10 Benedicts 2. Marshmallow: 1 marshmallow + 20 drops DW + 10 Benedicts 3. Potato Buds: 2 scoops + 20 drops DW + 10 Benedicts 4. Egg White Powder: 2 scoops + 20 drops DW + 10 Benedicts 5. Cornstarch: 2 scoops + 20 drops DW + 10 Benedicts 6. Distilled water: 20 drops DW + 10 drops Benedict’s solution (this is our control group)

Conclusion Explain how your hypothesis was supported/not supported by the data from your experiment My hypothesis _______supported. I predicted that that these foods ______________________ would have sugar and found out these foods _________________________ actually had sugar. Identify any possible errors or factors that could have affected your experiment Did any of the results surprise you? Why or why not?

Testing for Starch Problem: Which foods contain starch? Hypothesis: If I test ________for starch then it will (or will not) test positive for starch because ____________________

Data Chart – Testing for Starch Food Tested Color + sugar - no sugar * Add 3 drops of Lugol’s Solution to each TRAY CUP. * Look at the distilled water cup. It has no starch. * Compare the other cups to the distilled water cup. * If they changed color, then starch was present. * If they did not change color, then there was no starch.

Conclusion Explain how your hypothesis was supported/not supported by the data from your experiment a. My hypothesis was not supported. I predicted that _____________ would (would not) have starch but _________________________ it did have (did not have) starch. b. My hypothesis was supported. I predicted that ________________ would have starch and it did. (or would not have starch and it did not). Identify any possible errors or factors that could have affected your experiment Did any of the results surprise you? Why or why not?