PR-0552UK Primary Science - Book 2

What do plants need to grow?
Plants and animals ~ Activity 9
Objectives
• explore through the growing
of seeds, the need of plants for
water and heat
• investigate how plants respond
to light
Working scientifically
• Questioning
• Observing
• Predicting
• Investigating and experimenting
• Estimating and measuring
• Analysing (interpreting)
• Recording and communicating
Designing and making
• Exploring
• Making
Background information
Plants have certain requirements
to live.
1. Light: is essential for the
process of food production by
photosynthesis. Light does not
need to be direct; however, the
amount and intensity of light
required varies from plant to
plant.
2. Water: all plants require water,
which also contains minerals and
nutrients. The amount of water
required varies from plant to
plant.
3. Food: is the level of necessary or
additional minerals absorbed by
the plant. All plants require food.
In some cases, certain minerals
are essential for the plant to
survive. In others, minerals will
enhance growth.
Note:
The purpose of this experiment
is to identify the survival needs of
flowering plants. While the concept is
complex, it represents an opportunity
to demonstrate that separate
experiments are needed for light,
water and food; i.e. variables should
be isolated.
Before the lesson
Materials Needed
• Seeds (select easy-care fast-growing seeds such as beans, wheat or others
available locally); simple containers such as saucers, bottom of milk cartons
etc. to grow seeds, water, soluble fertiliser, cotton wool (or blotting paper).
Preparation
• Prepare sufficient containers to have nine per group of pupils (4–6 pupils per
group); seeds, water, cotton wool and fertiliser for each group.
The lesson
Stimulus
• Discuss what people need in order to survive. Write the suggestions on the
whiteboard. Discuss what pupils think plants need to survive. Write on the
whiteboard and compare lists.
What to do
• Discuss how pupils can test some of the suggestions by conducting an
experiment.
• Explain how pupils will test the need of a plant for light, water and food.
• Have each group prepare their experiments as follows. Parent helpers could
be used to assist if available.
Light: Three containers, labelled 1–3, with seeds resting on a bed of cotton wool. All watered so
cotton wool is moist to damp.
Place Container 1 in a dark cupboard – no light.
Place Container 2 in a position where light is received – no direct sun (on a shelf in the
classroom).
Place Container 3 in a position receiving direct sun (on a windowsill where some direct sun is
received).
Keep cotton wool moist throughout the experiment.
Water: Three containers, labelled 1–3, with seeds resting on a bed of cotton wool.
Container 1 – no water.
Container 2 – watered at the beginning only.
Container 3 – cotton wool kept moist.
Place all three together, on a shelf in the classroom.
Food: Three containers, labelled 1–3, with seeds resting on a bed of cotton wool.
Container 1 – no food.
Container 2 – fed at the beginning only.
Container 3 – fed regularly with soluble fertiliser.
Place all three together, on a shelf in the classroom.
• Note: The worksheet should not be completed until seed and plant growth has
been sufficient to differentiate the varying levels for growth.
• Pupils record their findings on the copymaster by drawing the results of each
experiment. Note: Work through each variable at a time.
• Based on their observations, pupils complete the grid at the bottom of the
worksheet to record how each variable affected the growth of the seeds.
Viewing Sample
After the lesson
Answers
• Teacher check
Additional activities
• Observe plants in the school grounds.
– Which plants are receiving ideal conditions?
– Which plants are not? What is missing?
30 PRIMARY SCIENCE ~ Prim-Ed Publishing ~ www.prim-ed.com