http://blogs.isb.ac.th/aitaka

1. Insert lab picture
(one with elodea,
thermometer in the
cylinder)

2. • Biology
• Importance of Photosynthesis
• Metabolism
• Environmental Issues

3. • What is photosynthesis?
• Process of
photosynthesis

4. • What is metabolism?
• How does temperature affect the rate of
chemical reactions?
• How does
metabolism affect
photosynthesis?

5. How does temperature
affect the amount of
oxygen produced by
Elodea’s photosynthesis?

6. • High Temperature  More
Oxygen Produced by Photosynthesis
• Low Temperature  Less
Oxygen Produced by Photosynthesis

7. Rate of photosynthesis at different
temperatures were measured by
– Counting the oxygen bubbles produced by
photosynthesis

8. • Independent variable: Temperature of
water
• Dependent variable: Number of Oxygen
Bubbles from Elodea
• Controlled variables
– Light intensity
– Length of Elodea
– Concentration of Sodium hydrogen
carbonate solution

11. 35
30
30
Average Numbers of Bubbles
25
21 20
20
17 17
15
15 Average Number of Bubbles
on 1-3 minutes
10
10
7 Average Number of Bubbles
on 13 to 15 Minutes
5
3
1
0
1
Temperature (± 1°C)
Temperature /± 1°C Average Number of Bubbles on 1-3 min. Average Number of Bubbles on 13 to 15 Min.
5 3 1
15 10 7
25 17 15
35 21 17
45 30 20

12. Average Number of Oxygen For Different
Temperature
30
Average Number of Oxygen (bubbles)
25
25
20
19
16
15
10 8.5
5
2
0
0 5 10 15 20 25 30 35 40 45 50
Temperature (Celcius)

13. • High temperature → More oxygen
bubbles
• High temperature increases:
– Rate of chemical reactions
– Metabolic activities in plant body
– Rate of photosynthesis

14. Weaknesses:
• changing effect of sodium hydrogen
carbonate
• Different sizes of bubbles
• Some bubbles caused by respiration
• the effectiveness and liveliness of elodea
What could be improved:
• more time for more trials
• more efficient way of counting bubbles
• Using fresh solution