New
New
Year 3

What plants need: do

I can set up a comparative test investigation to find out what plants need.

New
New
Year 3

What plants need: do

I can set up a comparative test investigation to find out what plants need.

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Lesson details

Key learning points

  1. Scientists can investigate what plants need by observing plant growth when requirements are removed.
  2. In a comparative test investigation, variables must be kept the same so only one thing is changed and one is measured.
  3. Scientists create a schedule for observations and choose a method to record change, such as a diary or photograph log.

Keywords

  • Plant - A plant is a living thing that often has roots, a stem and leaves.

  • Comparative test - In a comparative test, the thing that is being changed has labels, such as the types of materials.

  • Variables - Variables are the things that can be changed, measured or kept the same in a comparative or fair test.

  • Record - To record information is to keep it so that it can be passed on to others. This can be done in many ways including notes, photos and drawings.

Common misconception

Pupils may not see the need to use a second plant in their investigation that has all of its needs met, as they will be able to observe changes in the plant from which they are removing a requirement.

Explain that we need an additional plant with all of its needs met so that we can make direct comparisons between this plant and the one we are depriving of something.

To set up their investigations, pupils will need small plants that have very recently germinated from seeds. Peas, sweetcorn and sunflower seeds are all good choices for this as they germinate within a few days of being planted.
Teacher tip

Equipment

See additional materials.

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 does it mean to compare things?
Correct answer: To see how they are similar and different.
To see how they change over time.
To find out what their names are.
To find out how many there are.
Q2.
Plants require light, , air, warmth, room to grow, and nutrients from soil to grow and stay healthy.
Correct Answer: water, hydration
Q3.
What equipment could we use to measure the height of a plant?
thermometer
weighing scales
stopwatch
Correct answer: ruler
Q4.
Scientists can find out how things change by making of them over time.
experiments
estimations
Correct answer: observations
plans
Q5.
Which of these statements about plants is not correct?
An image in a quiz
Plants are living things that need certain conditions to stay healthy.
Correct answer: Plants need plenty of exercise to stay healthy.
Plants can take in nutrients from soil that help them to stay healthy.
Light is a requirement for plants to stay healthy.
Q6.
What are variables in a comparative test investigation?
Results that can be used to make conclusions.
Equipment used to take measurements such as rulers or thermometers.
Correct answer: Things that can be changed, measured or kept the same.

6 Questions

Q1.
Scientists create schedules for their observations. A good schedule for observing how plants grow over time would be to make observations…
An image in a quiz
every three minutes.
every three hours.
Correct answer: every three days.
Q2.
A comparative test is a type of investigation where...
scientists use secondary sources to learn more about something.
Correct answer: one thing is changed, another is measured and everything else is kept the same.
jobs are shared out equally between scientists.
Q3.
In comparative test investigations, the scientific word for the things that are kept the same, measured an changed is .
Correct Answer: variables, variable
Q4.
Jacob is carrying out a comparative test to investigate the question: How does having no light affect how a plant grows? Which variable will he change in his investigation?
An image in a quiz
the type of soil he uses
the amount of water his plant gets
Correct answer: the amount of light his plant gets
the size of the pot he uses
Q5.
Aisha is investigating the effect of having no light on plant growth. Which of these could she use to record her results?
An image in a quiz
Using her memory to keep track of changes.
Correct answer: Taking photographs of how the plants are changing.
Correct answer: Writing notes about what the plants look like over time.
Drawing a graph to show how much water the plants get.
Q6.
Sam is carrying out a comparative test to find out how a plant grows differently without any water. What could she measure over time for this investigation?
An image in a quiz
Correct answer: the height of the plants
the amount of soil in the pot
the volume of water given to the plants
Correct answer: the number of leaves the plants have

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