This clip could be used to stimulate a discussion on what plants need to grow. After watching the clip students could make predictions on what they believe a plant must have to grow successfully. Students could then design and plan an experiment to test one of these. In doing so, students could consider how to make it a fair test by ensuring they only change one variable each time. Cress seeds could be planted into small pots and kept under different conditions to test these variables. For example one plant could be watered each day while another receives no water at all, or one plant could be kept in a sunny spot while another is kept in darkness. Students could work in groups to test different variables. Students could make regular observations and then draw conclusions on what plants need to grow.