New
New
Year 11
OCR
Higher

The effect of light intensity on rate of photosynthesis in pondweed: plan

I can plan an investigation into the effect of light intensity on the rate of photosynthesis in pondweed.

New
New
Year 11
OCR
Higher

The effect of light intensity on rate of photosynthesis in pondweed: plan

I can plan an investigation into the effect of light intensity on the rate of photosynthesis in pondweed.

Lesson details

Key learning points

  1. Pondweed is a plant that photosynthesises in the light, releasing oxygen gas as a waste product.
  2. Planning an investigation into the effect of light intensity on the rate of photosynthesis in pondweed.
  3. Identifying the independent variable (light intensity) and planning how to vary it.
  4. Identifying factors that should be controlled and how they could be controlled (e.g. temperature).
  5. Planning methods to measure the dependent variable (number of bubbles and volume of gas given off).

Keywords

  • Rate - a measure of how much change occurs per unit of time

  • Light intensity - the amount of light reaching a given surface area in a period of time

  • Hypothesis - an idea, for example an idea about an outcome of an experiment, based on observations and understanding

  • Variable - a factor that can be changed during an experiment

  • Control variable - a factor that is kept the same during an experiment

Common misconception

Some pupils do not consider how to control variables carefully enough. This means results are likely to be less accurate and so do not provide conclusions that can be used to support a hypothesis.

Each type of variable is considered during the lesson and repeated to help pupils to understand the differences between each type of variable.

Use real practical equipment to provide pupils to think about the types of equipment that can be used and to help pupils analyse risk effectively. Ask pupils to handle the equipment and consider how they might use it, so they can approach the tasks with workable ideas.
Teacher tip

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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6 Questions

Q1.
What is the basic purpose of photosynthesis in plants?
to absorb nutrients from the soil
to produce carbon dioxide and water
Correct answer: to produce glucose and oxygen
to store sunlight
Q2.
Where in the plant cell does photosynthesis occur?
Correct answer: in the chloroplasts
in the mitochondria
in the nucleus
in the cytoplasm
Q3.
What is an independent variable in an experiment?
a factor that cannot be measured
Correct answer: a factor that is changed during an experiment
a factor that is kept the same
a factor that doesn’t affect the results of the experiment
Q4.
Which type of variable is kept the same during an experiment?
independent
dependent
Correct answer: control
Q5.
What is measured as the dependent variable in this photosynthesis experiment?
An image in a quiz
amount of light absorbed by the plant
Correct answer: number of bubbles and volume of gas given off
temperature of the water
the mass of the plant before and after the experiment
Q6.
What safety measures should be considered when handling experimental apparatus?
Ignore safety guidelines.
Use equipment without checking it first.
Correct answer: Wear safety goggles and handle equipment carefully.
Correct answer: Ensure all equipment is correctly set up before use.

6 Questions

Q1.
What is the main product of photosynthesis?
carbon dioxide
Correct answer: glucose
water
light
Q2.
Which part of the plant cell captures light for photosynthesis?
cell membrane
mitochondria
nucleus
Correct answer: chloroplasts
Q3.
What is the independent variable in an experiment investigating the effect of light intensity on the rate of photosynthesis?
carbon dioxide concentration
Correct answer: light intensity
temperature
type of plant
Q4.
Which of the following is an example of a control variable in a light intensity experiment?
Correct answer: distance of the plant from the lamp
type of plant
number of oxygen bubbles produced
change of colour of universal indicator
Q5.
How can the distance of the plant from the lamp be controlled in the experiment?
Correct answer: by using a ruler to measure the distance
Correct answer: by marking a fixed position for the lamp
Correct answer: by placing the plant on a stand at a set height
by trying to keep the plant and lamp in the same position throughout
Q6.
What would be plotted on the x-axis in a graph of light intensity and photosynthesis rate?
rate of photosynthesis
Correct answer: light intensity
temperature of the water
carbon dioxide concentration