1. Ardrossan Academy Dead Earth
Subtopic – Photosynthesis contd.

2. I will be successful if I can :
Lesson Title: Testing a Leaf for Starch
Learning Intention:.
Name the solution used to test leaves for starch and the colour change it produces.
Activity:
I will be successful if I can :
Safely test a leaf for Starch and remember the steps

3. Photosynthesis recap animation

4. Photosynthesis
Photosynthesis

5. GLUCOSE is produced during photosynthesis and stored as STARCH
If a leaf has starch in it, it means photosynthesis has been taking place
IODINE solution turns blue/black if starch is present

6. Testing a leaf for starch

7. Method - 2. PUT OUT THE BUNSEN BURNER Animation
1. Boil the leaf in water for 5 min
(to soften the leaf)
2. PUT OUT THE BUNSEN BURNER
3. Use the glass rod to transfer leaf into boiling tube
4. Place boiling tube back into the hot water to boil the leaf in alcohol
(to remove the green colouring)
5. Carefully lift the leaf out with glass rod and place in hot water to wash the leaf
6. Spread the leaf out on a dimple tile.
7. Test with Iodine solution
Animation
1. Boil in water
- (water in beaker)
2. Boil in alcohol
3. Rinse alcohol
off leaf
4. Test leaf with
Iodine solution
- (Bunsen switched off !! )

8. IF the iodine turns blue/black THEN the leaf has starch.
Starch present
Starch absent
In the presence of light green plants are able to make starch (food) in their leaves

9. What conditions do you think are needed for photosynthesis?
Aim
To investigate the conditions required for photosynthesis
What conditions do you think are needed for photosynthesis?

10. Before testing for starch After testing for starch Starch present
Condition missing
Before testing for starch
After testing for starch
Starch present
(yes/no)
None (control)
light
Chlorophyll
Carbon dioxide
dark

11. Method - 2. PUT OUT THE BUNSEN BURNER Animation
1. Boil the leaf in water for 5 min
(to soften the leaf)
2. PUT OUT THE BUNSEN BURNER
3. Use the glass rod to transfer leaf into boiling tube
4. Place boiling tube back into the hot water to boil the leaf in alcohol
(to remove the green colouring)
5. Carefully lift the leaf out with glass rod and place in hot water to wash the leaf
6. Spread the leaf out on a dimple tile.
7. Test with Iodine solution
Animation
1. Boil in water
- (water in beaker)
2. Boil in alcohol
3. Rinse alcohol
off leaf
4. Test leaf with
Iodine solution
- (Bunsen switched off !! )

12. Before testing for starch After testing for starch Starch present
Condition missing
Before testing for starch
After testing for starch
Starch present
(yes/no)
None (control)
light
Blue/black
yes
Chlorophyll
Some blue/black, some brown
some
Carbon dioxide
brown no
dark
Green
Green
white
Green
Green

13. Conclusion
I found out that (refer back to your aim)
Carbon dioxide, light and chlorophyll are needed for photosynthesis to take place.

14. Lesson 2 - Learning Intentions
Through practical work, name the conditions required for photosynthesis to take place

15. POSTER
Title – ‘Do plants need chlorophyll / light / carbon dioxide for photosynthesis’
Method, including diagrams, of how you carried out the experiment
Results – what colour did the iodine test produce
Conclusion, what do plants need for photosynthesis.
Word Equation