We will learn • The factors that affect the rate of plant growth. • The idea of limiting factors. Light intensity (Lux) 0 5 10 15 20 25 30 35 40 45 50 Number of bubbles per minute 0 17 27 36 43 46 48 52 60 60 60 Describe the pattern that the graph shows. Explain why the number of bubbles rises at first. Explain why the number of bubbles then stays the same. How could you get the plant to make more than 60 bubbles per minute? We will learn • The factors that affect the rate of plant growth. • The idea of limiting factors. We will learn • The factors that affect the rate of plant growth. • The idea of limiting factors. We will learn Carbon dioxide • The factors that affect the rate of plant growth. Water • The idea of limiting factors. Temperature Light Colour of light Chlorophyll can only absorb some types of light It speeds up or slows down chemical reactions It is needed for photosynthesis and it helps the plant support its leaves It is a raw material for photosynthesis It provides energy for the chemical reaction A – To find out if temperature affects photosynthesis. Temperature (oC) 15 30 45 60 Number of bubbles in 1 minute 5 17 38 0 B – To find out if the colour of light makes a difference to photosynthesis. Colour of light blue green yellow red Number of bubbles in 1 minute 27 4 16 24 Cut out and stick in each results table and draw a bar chart to display each set of results. Write a conclusion for each investigation. What will the gas at X be? Why did this covered leaf only have starch in its middle? What would you see if this leaf was tested for starch? Which leaf will have starch in it? The graph shows how chlorophyll absorbs different wavelengths of light. Why are trees green? The indicator is red. It turns yellow when carbon dioxide is added or purple when carbon dioxide is taken from it. What colour will each experiment go? Say why you think that each step is needed when you tested the leaf for starch. I boiled the leaf in water first so that… What do the results show about the leaf?