New
New
Year 11
OCR
Higher

The effect of light on the growth of seedlings: practical

I can measure, record and explain the growth response of seedlings to different light intensities.

New
New
Year 11
OCR
Higher

The effect of light on the growth of seedlings: practical

I can measure, record and explain the growth response of seedlings to different light intensities.

Lesson details

Key learning points

  1. Investigating the response of newly germinated seedlings to bright directional light (e.g. mustard seedlings)
  2. Accurately measuring the length of growth
  3. Producing accurate, labelled scientific drawings to depict the growth response
  4. Interpreting and describing the results
  5. Explaining the growth response of seedlings to light using ideas about auxins and phototropism

Common misconception

Pupils may think auxins move down the side of the stem that is nearest to the light and cause it to bend. Pupils may also think that sketched drawings are more accurate than scientific line drawings.

Auxins move down the shaded side causing cell elongation, which causes the seedling to grow towards the light. Line diagrams are representations that are clear and labelled; making them easy to read.

Keywords

  • Quantitative data - Data that is collected through taking measurements.

  • Qualitative data - Data that is collected through making observations.

  • Auxins - Plant hormones that affect the growth of plants.

  • Phototropism - Growth response stimulated by light.

  • Conclusion - A summary of the results of an investigation with data and scientific explanations

The seedlings must be watered and measured every day. The seedlings in partial light must be taken in and out of light regularly. A sample set of results or demo seedlings make the investigation more realistic in a school setting.
Teacher tip

Equipment

cress or mustard seeds, cotton wool, petri dishes, ruler

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).

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6 Questions

Q1.
Calculate the mean of these numbers: 40, 50 and 39.
Correct Answer: 43
Q2.
How many millimetres are there in a centimetre?
Correct Answer: 10, 10mm, 10 mm, ten, 10 millimetres
Q3.
Which of these are plant hormones?
nectar
Correct answer: gibberellins
oestrogen
Correct answer: auxins
pollen
Q4.
What effect does auxin have on shoots?
It inhibits growth.
Correct answer: It stimulates growth.
It has no impact on growth.
Q5.
What is a tropism?
A plant growth response to gravity.
A plant growth response to light.
A plant growth response to water.
Correct answer: A plant growth response to a stimulus.
Q6.
Which images correctly show phototropism?
An image in a quiz
Correct answer: a
b
Correct answer: c

6 Questions

Q1.
What is the height of this seedling in mm?
An image in a quiz
Correct Answer: 55, 55 mm, 55mm, 5.5cm, 5.5 cm
Q2.
What should you not do on a biological drawing?
An image in a quiz
stippling
Correct answer: shading
labelling
Correct answer: sketching
continuous lines
Q3.
After 5 days, which seedlings had increased the most in height?
An image in a quiz
Correct answer: the seedlings grown in the darkness
the seedlings grown in the partial sunlight
the seedlings grown in the full sunlight
Q4.
Which of the following conclusions can be made from this graph?
An image in a quiz
The seedlings grown in full sunlight were the healthiest.
It is best to grow seedlings in the dark.
The seedlings grown in partial sunlight have smaller leaves.
Correct answer: The seedlings grown in the dark increased the most in height.
Q5.
What is the plant response to light known as?
Correct Answer: Phototropism
Q6.
Look at this picture of a shoot. From which direction is the light coming and in which side of the shoot has auxin gathered?
An image in a quiz
the light is coming from the left; auxin has gathered in the left of the shoot
the light is coming from the left; auxin has gathered in the right of the shoot
Correct answer: the light is coming from the right; auxin has gathered in the left of the shoot
the light is coming from the right; auxin has gathered in the right of the shoot

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