Leaf Disks & Yeast Balloons

Station 1: Floating Leaf Disks

Pull the air out of the leaf disks so they sink. Then put Syringe A under the lamp and Syringe B in the dark box. As photosynthesis makes O₂, gas fills the leaf and the disks float back up.

Station 2: Yeast Balloons

Set up two flasks of yeast in a warm water bath. Flask A gets sugar. Flask B is the control. As the yeast carry out cellular respiration, CO₂ gas collects in the balloon.

1. Set the water bath temperature (37 °C works well).
2. In each flask: add 100 mL of water, then 1 yeast packet.
3. Flask A: choose 1, 2, 3 or 4 sugar packets. Any amount works. Write down how many you used.
4. Flask B: leave it at 0 sugar packets. It is your control.
5. Stretch a balloon over each flask, then start the timer.

Analyze Your Data

Your graphs are drawn from the numbers you recorded. Use your data tables to answer the rate questions.

Claim · Evidence · Reasoning

Answer the question using your own data. Click a sentence frame to start a box, then fill in the blanks.

Check Your Understanding

Inputs and outputs of each reaction. You get one try per question.

Turn In Your Lab

Signed in to The Lab Games? Press Turn in my lab to send your data, rates and CER to your teacher's gradebook (your Check answers are turned in from the Check tab). You can keep working and turn in again. Not signed in? Copy your report and paste it where your teacher asks.