Leaning to the Light

Leaning to the Light

Leaning to the Light

Follow FizzicsEd 150 Science Experiments:

You will need:

Two clear plastic jars

One packet of bean seeds

Paper towels

Water

One dark Cupboard

One Sunlit Window

 

 

1

Place the paper towels around the inside edge of each jar.

2

Place a bean seed between the paper towel and the side of the plastic jar.

3

Wet the paper towels and place the jars on a sunlit window ledge until germination.

4

After germination, place one jar inside a dark cupboard within the same room.

5

The plant placed in the dark cupboard becomes white, grows poorly and dies first.

Why Does This Happen?

The movement of plants towards light is called ‘phototropism’. ‘Photo’ means light, whereas tropism means ‘to move’. Plants grow by plant cells getting longer or splitting into new cells. The cells on the side away from the light grow much faster than those on the sunlight side. This causes the plant stems to bend towards the light. Phototropism allows the plant leaves to get the full benefit of the sunlight energy.

The green chemical in plant leaves is called chlorophyll (“Clo – ro – fill”). Chlorophyll changes sunlight into energy and sugar. The plant in the dark cupboard loses its green colour because sunlight helps to make chlorophyll.

Without chlorophyll plant growth stops as there is no more energy or sugars being produced, and the plant dies.

Learn more!

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