How do you set up a practical to investigate phototropism?

To investigate phototropism, set up a simple experiment using seedlings, a box with a hole for light, and observe their growth direction.

To start, you'll need a few materials: a box (preferably cardboard), some seedlings (cress works well), a light source, and some soil or cotton wool to grow the seedlings in. Cut a hole in one side of the box - this is where the light will enter from. Plant your seedlings in the soil or cotton wool and place them in the box, then position the light source so it shines through the hole.

The idea is to create an environment where the only source of light is coming from one direction. This will allow you to observe the effect of light on the growth direction of the plants, which is essentially what phototropism is. Remember, phototropism is the growth of organisms in response to a light stimulus. In plants, this is often observed as the plant bending or growing towards the light source.

Make sure to observe and record the direction of growth each day. You should start to see the plants bending towards the hole in the box where the light is coming from after a few days. This is because the plant is growing towards the light source, demonstrating positive phototropism.

For a more comprehensive experiment, you could set up multiple boxes with holes on different sides, or use different types of plants to see if there are any variations in their phototropic responses. Always remember to handle the plants gently and keep the conditions as consistent as possible for accurate results.

This practical experiment is a great way to visually understand and appreciate the phenomenon of phototropism. It's fascinating to see how plants can sense and respond to their environment, isn't it?