Question

you carry out an experiment where you change the light intensity experienced by a piece of canadian pondweed by changing the distance between the pondweed and a lamp supplying it with light. write down four things which must be kept constant for this experiment to be a fair test

Answer 1

Think about the things that could vary in your experiment. For example, you'd want to make sure that the intensity emitted by the lamp stays the same throughout the experiment - it would defeat the purpose to use a light bulb as a source and turn the light off half way through the experiment.

Answer 2

thanks