Question

Sophia is testing an effect of different volumes of water on the growth of duckweed. She set up the experiment that is shown below. Three beakers, all the same size, are set up with cool tap water and duckweed in them. The first beaker contains 100 mL of water and 20 fronds of duckweed. The second beaker contains 200 mL of water and 50 fronds of duckweed. The third beaker contains 300 mL of water and 40 fronds of duckweed..

Based on this setup, the most likely source of error in this experiment is
a)the sizes of the beakers that are used.
b)the depth of the water in each beaker.
c)the temperature of the water in each beaker.
d)the number of duckweed plants in each beaker.

Answer 1

The most likely source of the error in the Sophia'a experiment to 'test the effect of amount of water on the growth of the duckweed' will be the different number of the plants in the each beaker. When conducting an experiment to check the effect of a substance, it is necessary that all the set ups should be kept in completely similar environment and under similar conditions. In Sophia's case, she should have used similar number of plants in each beaker as putting more in one will increase the competition and will affect the results.

Hence, the answer is 'Option D - the number of duckweed plants in each beaker'.

Answer 2

The correct answer is letter D. The number of duckweed plants in each beaker would most likely be the source of error in the experiment because it would be inaccurate or hard for her to determine which of the plants grew first hand in the experiment.