Saturday, 3 March 2012

Runner Bean Experiment

This experiment was very nostalgic for me, I remember being very excited to show my parents my runner bean I had grown at school. It is simple yet very effective and fun way to show children what plants need to grow.

Firstly we looked at the effect that light has on the growth of plants. We filled two glasses full of wet cotton wool balls and planted the beans between the cotton and the glass so we could easily observe what was happening. We then used lolly pop sticks to label one glass light and the other dark.

Light vs Dark
The light glass was then placed on a sunny window sill and the dark was placed inside a cupboard. Over the next couple of weeks we checked our beans at the same time each day, watering when necessary and took pictures of our observations.

Day two

After two days we had our first sprout. My children were a little surprised to find that it was the bean planted in the dark. I explained to them that plants were very clever and the bean planted in the dark will grow faster because it needs to grow higher to try find some sunlight.

Day four

On day four the light plant had finally grown a sprout. In hind sight I should of soaked the beans in water over night before starting the experiment to make it a little quicker. My children get really excited checking on their beans everyday but this is quite a long experiment, so it is a good idea to also plant some quick growing plants in the garden or grow a sproutapouch. Children can get quite impatient waiting for things to grow.

Day 9
Day 10

Day 11
Day 12


 By day twelve both plants had sprouted and had a stem and two leaves. The noticeable difference being that the dark plant was taller paler and had smaller leaves.

Day 13
Day 16

We are now coming to the end of part one of this experiment and my children can clearly see that the dark plant has grown faster but does not look as healthy and green as the plant grown in the light.

This is a great opportunity to explain a little about photosynthesis. Depending on age go into as little or detailed description as you wish. My children are fairly young so I kept it as simple as the plant uses the light air and water to make food to give the plant energy to grow. If you want to go into a little more detailed the BBC Gardening website has a nice little section on this.

We are now ready to move on to part two of our experiment. Water vs no water.

We repeated the same experiment looking at what effect water has on the growth of plants. We filled one glass with dry cotton wool balls and another with wet and placed both on a sunny window sill.

Water vs No water

Again we checked on our plants at the same time everyday, watered the glass labelled water when necessary and took photos of our observations.

Day three
Day five
Day eight
Day ten
Day eleven

Day thirteen

Day fifteen

Day sixteen

We are at the end of our experiment and my children can clearly see that plants will not grow without water. We are going to follow this up with a experiment  involving celery and food dye to show my children how plants absorb water and uses the stem to transport it to the rest of the plant. 

Our next step is  to re plant our beans in a pot of compost in the garden in hope to be able to harvest some pods in July. For tips on how to grow beans check out the BBC gardening website. 


  1. Loved this, great idea!!! This is learning at it's best.

    1. Thankyou for your lovely comment. I am pleased you liked my post we had great fun growing our beans :)