Whether you are conducting a school experiment to illustrate seed germination or are creating a science project, growing beans in cotton wool is an interactive project for children. Children watch the seed germinate, the roots develop, and the plants sprout and grow. All you need is a bean seed, damp cotton wool and a clear planter or bowl.
Soak the bean seeds overnight. Soak enough so each person in the class gets a bean. Wet the cotton wool and place it inside the container. Add a few bean seeds to each container on top of the cotton wool and put the container in a bright window. As the cotton wool dries out, water it. Have pupils record how the beans grow and change. Encourage the children to identify the plant life cycles.
Give the children a second pot filled with soil that they can place next to their original experiment. Have the children plant bean seeds in the soil and observe how quickly the plant grows in soil. You can also place a cotton-wool experiment inside a dark cupboard. Add a fourth seed in a sunny location, but do not water the cotton wool after the seeds are placed on it. Let the children record how and at what rate the different seeds grow. Encourage them to make deductions about light and soil.
You can illustrate the effects of smoking through a similar experiment. Plant the first bean plant as you did in the project basics, but for the second one, add cigarette smoke. Place your cotton wool inside a plastic detergent container. Insert a tube that can accommodate a cigarette. Light a cigarette, insert it into the tube and let it burn. Remove the cigarette and the cotton wool. Show the tar accumulation on the cotton wool to the children. Use the tar-soaked cotton wool in your basic project to reveal how the tar affects bean growth. Keep the lighted cigarette away from the children and conduct this part of the experiment outside so you will not expose the children to smoke.
You can add or change numerous factors, such as light, air flow, pesticides and herbicides, and temperature, to illustrate the optimal conditions for seed growth. Use a sealed bag to restrict air flow or add fertiliser to seeds, seedlings or growing plants to observe their effects on each stage of the life cycle. Change the pH of the water you add to the cotton wool to see how acidity and alkalinity affect the plants. Plant one seed in a container that is much too small to see how restricted root growth affects plants. You can even use your bean plants to conduct experiments about insects. For instance, find out what colours of cloth attract insects. Test how plants and soil temperature are affected by coloured mulch or different types of mulch.