This list suggests resources which can be used to investigate photosynthesis.
In primary school (Year 3), students will have explored the requirements of plants for life and growth (air, light, water, nutrients from soil, and room to grow) and how they vary from plant to plant, as well as investigating the way in which water is transported within plants. At this age the science will have been covered at a fairly basic level, but it is worth spending some time at the beginning of the unit to assess prior learning.
At Key Stage Three, photosynthesis is looked at in more detail, including:
• plants making carbohydrates in their leaves by photosynthesis and gaining mineral nutrients and water from the soil via their roots
• the role of leaf stomata in gas exchange in plants
• the reactants in, and products of, photosynthesis, and a word summary for photosynthesis
• the adaptations of leaves for photosynthesis.
Visit the secondary science webpage to access all lists: www.nationalstemcentre.org.uk/secondaryscience
Links and Resources
This activity allows students to see how chlorophyll can be energised and how this causes it to fluoresce. Chlorophyll in plant leaves absorbs red light and passes the energy on to other parts of the plant, hence leaves look green. But if there is nowhere for the energy to go, it is released as light again.
Cabomba is a highly reliable plant, especially compared to Elodea, for demonstrating photosynthesis.
Students observe bubbles of oxygen which are released as the plant carries out photosynthesis. These bubbles can be counted and the rate of bubbling can give an indication of the rate of photosynthesis. If you alter the light intensity, does the rate of bubbling vary?
Having established that plants take in carbon dioxide and water, molymods are a hands on way to demonstrate that carbon dioxide has mass and when reacted with water can produce the basis of plant material - glucose.
The top trumps game can extend the idea by illustrating how glucose can be used to build more complex molecules.
Prior understanding of atoms, elements, compounds and chemical reactions is needed.
Once students have understood that carbon dioxide is the source of carbon in the starch formed by photosynthesis, and that starch is a carbohydrate made from the polymerisation of glucose, they can carry out this investigation to see whether starch is produced in leaves with and without light.