1.1. A student set up an investigation into the limiting factors of photosynthesis.

His set up is shown in Figure 5 below:

Figure 5

Identify the limiting factor being investigated in this practical.

1.2. The student carried out an investigation to find out the effect of light intensity on the rate of photosynthesis by moving the light source further and further away from the aquatic plant and counting the bubbles produced per minute at each distance.

The results can be seen in Table 1 below:

Table 1

One of the results recorded was an anomaly.

Identify which result was anomalous and explain your choice.

1.3. Describe the trend shown by the data in Table 1.

1.4. The student evaluated his method and decided that counting bubbles is an inaccurate way of measuring the rate of photosynthesis for two reasons.

1. It does not take into account the fact that there may be bubbles of different sizes

2. Tiny bubbles may be hard to see and so may not be counted at all

Suggest a more accurate method which could be used to collect information about the amount of oxygen gas produced as the aquatic plant photosynthesizes.