4. Disscussions

4.1 Key findings

In most of the beakers labeled B (1 spray of insecticide), the duckweed seemed to thrive. Also, in setup 1, there was a sharp increase in the duckweed in Beaker C on the third day. From this it can be determined that duckweeds used as a bio indicator of water quality is not very accurate as the growth of duckweed fluctuates based on our results.

4.2 Explanation of key findings

The experiment showed that certain amount of insecticide helped the duckweeds to grow. This is probably because the insecticide had contained crop-friendly chemicals which helped the duckweeds to grow instead of killing the duckweed.

However, the detergent killed most of the duckweed as it contains toxic ingredients that are harmful to duckweeds.

4.3 Evaluation of hypothesis

Our hypothesis was wrong as the duckweed seemed to grow better in a slightly polluted water condition for example the beakers containing a spray of insecticide. This tells us that duckweeds may not be a very good bioindicator for water quality.

4.4 Areas for improvement

We could have placed the duckweeds into direct sunlight so it would be more natural and give a more accurate result. We should not have placed our set-up in the lab as the surrounding temperature and exposure to sunlight is not constant. We could also have added more duckweeds to the experiment so as to analyse and have a better view as it was too little and hard to observe the growth of the duckweeds.

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