Transformation of Energy During Digestion

Lab Investigation:

Purpose: To find our what type of energy is released during digestion

Hypothesis: I think that ________________ energy is released when chemical bonds are broken during digestion.

Safety and Clean Up

• Wear goggles – send a safety person to pick them up for your table.

• No eating or drinking• Clean up – pour leftover waste in waste

container at front of room. Throw away paper plate in trash.

• Wash out beaker, scissors, tweezers, with soapy water, and dry with paper towel.

Procedure:

1. Send one person from your group to get materials. (beaker, scissors, tweezers, pair of gloves, paper plate, tray)

2. Send one person with the plate and tweezers to pick up the liver piece for your group.

3. One person will wear the gloves and then cut the liver into smaller pieces with the scissors. Leave the pieces of liver on the paper plate. Keep the gloves on until we have finished the activity, then put the gloves in the trash. Put the scissors in the soapy water container.

What kind of change took place when the person cut the liver with scissors? Physical or chemical? __________________________Explain why ______________________________________________________________________________________________________

4. Send one person with the small beaker (be careful – glass) to pick up the 20 mL of Hydrogen Peroxide in the beaker. (H₂O₂ ) Place the beaker on the tray in case of a spill.

5. Have one person pick up the Lab Quest data collector for your group. Follow your teacher’s directions for preparing the Lab Quest.6. Have one person hold the temperature probe upright in the beaker. The probe must be HELD in place. Do not let go without holding it because your beaker will tip over!!

Turn on Lab Quest (top left corner)

Click on Home screen (picture of small house) and then on Rate:

Set all settings to the following

ThenGo click “OK”

Go back to home screen. Find green “go” button.

7. WAIT for directions from your teacher before carrying out this part of the investigation. Prepare for the activity by having the one person hold the probe, another person watching the Lab Quest being ready to push the green start button, and another person ready to add the liver to the beaker one piece at a time with the tweezers. When all group members are ready, wait for the signal to start.

Get ready, get set, and….

• What type of change took place after the liver was added to the H₂O₂?

• Physical or chemical? _____________________________________

Go!

Click on the small table icon in the top toolbar.Make a table like this one and record the data on the chart.

Write down your data in the chart. Copy it in your notebook.

Time (min) Temperature (⁰C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Graphing your data

Click on the Graph icon on the top toolbar.

Draw your graph (caution: it may not look like this one!)

Conclusion:

(answer the questions below, tell what happened)• What happened to the temperature in the

beaker when the liver was added to the H₂O₂?__________________________________

• What type of energy WAS released? _______________________________________

This experiment was to simulate what process?