Photosynthesis is the process by which plants produce food from carbon dioxide, water and sunlight. During photosynthesis in the chloroplasts of leaves, carbon dioxide and water are converted using energy from sunlight into glucose and oxygen. The word equation for photosynthesis is carbon dioxide + water → glucose + oxygen. The balanced chemical equation is: 6CO2 + 6H2O → C6H12O6 + 6O2. This lesson teaches students about the process of photosynthesis and how to write and balance the chemical equation.

1. P H O T O S Y N T H E S I S
Settler Activity: Solve the anagram
(rearrange the letters to make one word)
I T S P Y T H O N S H O E S

2. The Science
Game

3. Your category is…
Photosynthesis

4. Write a fact about
photosynthesis on your white
board
Starter:
You have 2 minutes

5. Stand up….

6. 



X
It’s something to do with plants
It produces oxygen
It uses sunlight
It’s to do with cameras
Sit down if your answer is listed here…
It’s how plants make food for growth

7. Those of you still standing,
let’s find out what else you
know… do you have a unique
answer?

8. Photosynthesis
Learning Outcomes:
By the end of this lesson, you will be able to:
• Write a word equation for photosynthesis (6)
• Describe what happens (and where) in photosynthesis (7)
• Explain how to balance a symbol equation for photosynthesis
(8)
Lesson Objectives:
• To understand the process of photosynthesis
• Be able to explain what is happening to the molecules in
photosynthesis

9. So, what is photosynthesis?
How could you write this in a shorter version? Have a
go in the back of your books.
•Photosynthesis is the process by which
plants take in carbon dioxide from the air,
and water through their roots. Using energy
from the sun, these are combined to
produce glucose for the plant and oxygen as
a waste product.

10. How did you do?
One way to write the process is using the word
equation
carbon dioxide + water  glucose + oxygen
Write this down
(Sunlight)
(Energy)

12. Recap on plant cells
Label the diagram on your worksheet
Chloroplasts
Contain chlorophyll, the
green pigment in leaves,
when photosynthesis
occurs
Cell Membrane
Controls what enters and
exits the cell
Cell Wall
A strong rigid wall that
provides support for to
the cell
Nucleus
Controls the cell
Vacuole
A space in the cell that
contains sap
Cytoplasm
A jelly-like substance that
contains organelles
Starch
The insoluble (stored)
form of glucose

13. Chloroplasts and Chlorophyll

14. Chloroplasts and Chlorophyll
Chloroplasts contain chlorophyll – This is where photosynthesis takes place
The molecules are chemically changed to produce new molecules
Plants are called producers because they produce their own food
Carbon
dioxide
Water
Oxygen
Glucose

15. Label your diagrams
LIGHT
from sun
CARBON DIOXIDE
diffuses from the
air
WATER
from soil
GLUCOSE
for biomass
and energy
CHLOROPHYLL
in the leaves
OXYGEN
released into
atmosphere

16. To understand how this works, we need to look at
the chemical elements and molecules involved
How?

17. The video shows you how small atoms really are!

18. Using Nano Simbox
1. Collect a tablet, open the web browser
2. Go to: student.nanosimbox.io
3. Enter the software using the code below, your email and name
4. Build Carbon Dioxide, Water, Glucose and Oxygen by pressing
the purple icon with these molecules. Choose the level of
difficulty you prefer.
5. Write down the completed chemical formula for each of these
molecules on your worksheet (the letters and numbers)
6. Then write down the formula for photosynthesis replacing the
words with the chemical equations
Code: XXXXXXX Food > Food webs > Photosynthesis

19. (Sunlight)
(Energy)
carbon dioxide + water  glucose + oxygen
carbon dioxide water glucose oxygen+ +CO2 H2O C6H12O6 O2
Oxygen always goes around in pairs unless
attached to another element
Word equation for photosynthesis
How did you do?
Chemical equation for photosynthesis
Wait!
We’re not done yet – this equation isn’t balanced –
you need to have the same number of each
element on each side of the equation

20. The rules of balancing equations
CO2 + H2O  C6H12O6 + O2
• Work out how many of each element you have on
each side
• The small number next to an element is how
many of that element there are in that molecule
- You cannot edit this
• You need to work out how many you have to times
an element by to balance it

21. The rules of balancing equations
CO2 + H2O  C6H12O6 + O2
• On this side we have
• 1 x C
• 3 x O
• 2 x H
• On this side we have
• 6 x C
• 8 x O
• 12 x H
Let’s put 6 molecules of Carbon Dioxide in

22. The rules of balancing equations
6CO2 + H2O  C6H12O6 + O2
• On this side we have
• 6 x C
• 13 x O
• 2 x H
• On this side we have
• 6 x C
• 8 x O
• 12 x H
REMEMBER: You cannot change the small
numbers, so we now need 12 x H on the left

23. The rules of balancing equations
6CO2 + 6H2O  C6H12O6 + O2
• On this side we have
• 6 x C
• 18 x O
• 12 x H
• On this side we have
• 6 x C
• 8 x O
• 12 x H
Look at the totals below – Now we need to
equalise the O on the right

24. The rules of balancing equations
6CO2 + 6H2O  C6H12O6 + 6O2
• On this side we have
• 6 x C
• 18 x O
• 12 x H
• On this side we have
• 6 x C
• 18 x O
• 12 x H
It matches! The equation is balanced!

25. The balanced symbol equation for
photosynthesis is:
6CO2 + 6H2O  C6H12O6 + 6O2
Write this on your worksheets

26. The Science
Game

27. Molecules and cells in
photosynthesis
Plenary – What can you remember?

28. _A_E_
1

29. _A_B_N D_O_I_E
2

30. G_U_O_E
3

31. _X_G_N
4

32. _H_O_O_L_S_S
5

33. WATER
CARBON
DIOXIDE
GLUCOSE OXYGEN
Molecules and
organelles in
photosynthesis
CHLOROPLASTS
_A_E_
_A_B_N
D_O_I_E
G_U_O_E _X_G_N _H_O_O_L_S_S
1 2
3 4 5

34. How would you teach
balancing equations to
someone else?
Creative thinking plenary:
You have 3 minutes

35. Extension Activity - Photosynthesis true or false
1. Plants get food from the soil ……..
2. Plants make food in their green leaves ……….
3. Water gives the plant the food it needs ……….
4. To make food a plant needs oxygen ……….
5. Chlorophyll is green ……….
6. Photosynthesis makes chlorophyll ……….
7. Photosynthesis is when the plants make food in its leaves ……….
8. A plant needs water to make food ……….
9. The plant gets food from the sun ……….
10.Sunlight is needed for photosynthesis ……….
11.The speed of photosynthesis is always the same in a leaf ……….
12.The speed of photosynthesis depends on the temperature ……….

36. Extension Activity - Answers
1. Plants get food from the soil.
2. Plants make food in their green leaves.
3. Water gives the plant the food it needs.
4. To make food a plant needs oxygen.
5. Chlorophyll is green.
6. Photosynthesis makes chlorophyll.
7. Photosynthesis is when the plants make food in its leaves.
8. A plant needs water to make food.
9. The plant gets food from the sun.
10. Sunlight is needed for photosynthesis.
11. The speed of photosynthesis is always the same in a leaf.
12. The speed of photosynthesis depends on the temperature.