Light and photosynthesis

Light and photosynthesis

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses

Below is a table of results obtained by a year 10 student who was looking at how different light intensity affected the rate of photosynthesis in two different types of plant.

Light Intensity
(Lux)		 Photosynthesis Rate
(Photosynthetic Unit)
Plant Type A Plant Type B
10 5 5
20 9 29
30 16 41
40 23 49
50 32 54
60 42 58
70 55 60
80 72 60
a)
Draw line graphs for the above data on the grid below. Remember to give the graph a key, and scales for both axis.

Photosynthesis rate
(Photosynthetic unit)

 
Photosynthesis Rates of Two Plant Types

Light Intensity (Lux)
b)
What was the rate of photosynthesis for Plant Type B when the light intensity was 45 lux? _______
 
c)
On your graph, draw and label a line for plant type C. Plant type C has a lower rate of photosynthesis than Plant Type A for light intensities up to 40 lux. Above 40 lux, Plant Type C has a faster rate.
d)
Why is Plant Type B more likely to live on a forest floor with little light?
 
 
 
 
Task administration: 
This resource can be completed with pencil and paper.
Level:
5
Curriculum info: 
Science, Communicating in science, Living World
Keywords: 
Life processes, plants, photosynthesis, graph construction, graph interpretation
Description of task: 
Students are given results from an investigation looking at light intensity and its effect on the rate of photosynthesis in two plants. Students are required to draw line graphs of this data and then answer a number of questions pertaining to this.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Interpret representations
This resource provides opportunities to discuss the relative benefits of using tables or graphs to convey the same set of data.
Science capabilities: 
Interpret representations
Answers/responses: 

 

Y11 (04/01)

a)

Draws line graph. (See below).
Graph has a key and correctly numbered axis.
Correctly draws two lines with no plotting errors.

1-2 errors made in plotting, (joining lines to zero is counted as 1 error).

very easy
easy
2 correct – moderate

1 correct – very easy

b)

52 ± 1

easy

c)

See graph below for an example.
Line showing a lower rate of photosynthesis up to 40 lux, and a higher rate of photosynthesis above 40 lux. (The line should cross the line of plant A at 40 ± 3 lux).
Line begins at 10 lux and finishes at 80 lux. (If the lines for A and B started at the zero mark, this line can also start there without penalty).

difficult

 


moderate

d)

Because of its higher photosynthesis rate in lower light.

difficult