WHAT DO PLANTS NEED TO GROW? class 3 B

We have done an experiment in class 3B to see what plants need to grow.

Hypothesis (what we think is the answer): They need water, soil, sunlight and air to grow.

The experiment:

1st: we put some beans and lentils in wet cotton, until a small root and a small stem begin to grow.

2nd: We plant each of the little plants in different conditions, and observe them to see what happens:

This bean plant has got good soil, water and sun.

This bean plant has good soil and water, but we put it in the cupboard, so it hasn´t got any light.

We plant the lentils in three different pots: two with soil and one with sand. We put in the cupboard without light one of the pots with soil.

We let this bean plant in the cotton, with no soil.

We put this bean plant in a plastic bag so it has very little air.

The bean plant on the left has too much water, the one on the right no water.

3rd. We observe the changes in the plants:

After 2 weeks:

The lentils in soil grow up, the lentils in sand are not strong, they fall down.

The bean growing with soil, water and sunlight has big green leaves The one in the cupboard, without sunlight is not green, and has got small leaves.

The plant without water is dead.

And this is the final observation before Christmas holidays:

The plant with water, sun, soil and air is very healthy. It has big leaves and flowers.

The plant without sun is yellow and small. The leaves have died and it has no flowers.

The plant growing in cotton, with no soil, is green. It is not big. It hasn't got any flowers.

The plant with no water is dead.

The plant in the plastic bag is small, crooked and strange. It has got leaves and flowers. 

The plant with lots of water is green with healthy leaves. It hasn´t got any flowers.

The lentils in sand are almost dry. The leaves are not healthy.

The lentils in good soil are green. The leaves are small and healthy.

The lentils in the cupboard, without sunlight, have got white stems. The leaves are small and yellow.

4th. Conclusions: To help you get to the conclusions,
Look at the pictures and read, then try to answer these questions:
1. After the experiment, do you think our hypothesis are correct?
2. Why, or why not?
3. Do you think there is anything wrong in the experiment?
4. Is there anything we still don't know? 
5. Can you think of another experiment that can help us discover it or correct what is wrong?