What do seeds need to grow? Science experiment What do seeds need to grow? In this experiment we are going to investigate what conditions seeds need to germinate. Equipment: Beakers Water Cotton wool Soil Box or dark room Cling film/plastic bag Seeds e.g. bean or pea Ice blocks Marker pen Method: Decide on the number of conditions you want to investigate. As an example, we investigated if seeds need soil, water, light, air and warmth to germinate. Label your beakers e.g. soil and no soil, water and no water, air and no air, light and no light, warmth and no warmth. Place cotton wool into all beakers except the one marked soil; add soil to this last beaker. Add 2 or 3 bean seeds to each beaker. Water all of the beakers except the one marked no water. Place the beaker marked no light into a box or a dark room. Wrap cling film around the top of the beaker marked no air and place this in a sealed plastic bag. The beaker marked no warmth was surrounded by ice blocks (you could use a fridge to show lack of light and warmth). Place your beakers onto a sunny window sill. Water the beakers (except the no water beaker) occasionally to make sure they stay moist. Observe the changes in your seeds after 7-10 days and record these in your experiment. A strategic health initiative from Project HOPE UK

What do seeds need to grow? Science experiment What do seeds need to grow? Observations: Monitor your experiment and record the changes do you see. Try to answer these questions: What changes have you noticed? How long did it take for the changes to occur? What are the differences you observed between the seeds germinating under the different conditions? What do you think this tells you about how seeds germinate? Extension: What other conditions could you investigate? What do you need to do to make this a fair test? Why do you think these differences exist? What are the differences between the conditions needed by seeds and plants? A strategic health initiative from Project HOPE UK

What do seeds need to grow? Science experiment What do seeds need to grow? A strategic health initiative from Project HOPE UK Record your observations and think about why they have occurred. Recording: What did you do ? What changes did you see ? Why do you think you see differences ?

What do seeds need to grow? Science experiment What do seeds need to grow? A strategic health initiative from Project HOPE UK Example: Recording: What did you do? I investigated 5 conditions (light, water, air, warmth and soil) to see their effect on how well seeds germinate. I labelled my beakers e.g. soil and no soil, water and no water, air and no air, light and no light, warmth and no warmth, so that they didn’t get mixed up during my experiment. I placed cotton wool into all of my beakers except the one marked soil; I added soil to this beaker. I added 3 bean seeds to each beaker and watered all of the beakers except the one marked no water. I placed the beaker marked no light into a sealed box. I wrapped cling film around the top of the beaker marked no air and placed this in a sealed plastic bag. I surrounded the beaker marked no warmth with ice blocks. The beakers were placed onto a bright windowsill. To make it a fair test, I used the same number of seeds and the same size beakers for all experiments. I used the same amount of cotton wool in each beaker and watered each beaker with the same (measured) amount of water. All beakers were placed on the same windowsill to make sure they all got the same amount of light. What changes did you see? After 7 days, most of the seeds showed signs of germination, apart from the seeds which had received no water. Most of the seeds had begun to open and form roots. Some of the seeds had started to form a stem and leaves. The seeds which had received no warmth had begun to open slightly but had not yet formed roots, a stem or leaves. The seeds sown with and without soil, with and without light and with and without air had all germinated and had formed roots and stems.

What do seeds need to grow? Science experiment What do seeds need to grow? A strategic health initiative from Project HOPE UK Example: Recording: Why do you think you see differences? The seeds grown in soil and without soil, in the light and without light and with fresh air and without air all germinated which suggests that soil, light and air are not needed for seeds to germinate. This makes sense because seeds usually germinate underground where light and fresh air is scarce. Nutrients from soil are not needed as the seed has its own food supply. The experiment suggested that water and warmth are important for seeds to grow. The seeds which were grown in colder conditions did not germinate within 7 days. The seeds which were not given any water did not change at all. This makes sense as we know that seeds do not germinate when we buy them in packets. They require water to start the germination process. The seeds grown with and without light germinated but there were some differences in the stem and leaves formed. The seeds grown in the light formed a green stem and leaves; the seeds grown in the dark formed a pale yellow stem and leaves. This suggests that once the seed has formed a plant with a stem and leaves, it is important for the plant to have light to be healthy. Light is needed by the plant to make chlorophyll, which gives the plant its green colour. The plant uses chlorophyll to make nutrients for the plant. Light No light