Question

1. Make a hypothesis about how carbon dioxide affects the rate (speed) of photosynthesis:
If I give a plant extra CO2, then the rate will __________________________ (increase or decrease?)

because
2. Set the thermometer to 25°C (room temperature).
3. Set the light intensity to 20.
4. Count the number of bubbles per minute. To do so:
a. Click the green button on the timer.
b. Count how many bubbles form in 60 seconds (you could also go for 30 seconds
and multiply by two).
c. Record your data in the “no CO2 added” box.
d. Hit the red button to stop the timer.
5. Now you are going to see how carbon dioxide affects photosynthesis. Leave the temperature at 25 and the light intensity at 20.
6. Increase the carbon dioxide available to the plant by clicking on the “CO2” container once; it should be now be half empty.
7. Count the bubbles per minute as directed in step 4. Record your data.
Carbon Dioxide Setting Bubbles per minute
No CO2 added
CO2 added






Analysis:

A) What is the species name of the plant being used?

B) Why can you use bubbles to track the rate of photosynthesis?


C) Based on your data, how does the amount of carbon dioxide available affect the rate of photosynthesis?

D) What is the independent variable in this experiment- what are YOU changing?


E) What is the dependent variable- what are you measuring?


F) What is one constant? (something that stays the same in every single trial)

Answer 1

Answer:

Carbon dioxide concentration

Carbon dioxide - with water - is one of the reactants in photosynthesis. If the concentration of carbon dioxide is increased, the rate of photosynthesis will therefore increase.