Monitor cress and see if different water types affect their growth.

        Measuring cylinder

        Planting pots

        Ruler

        Soil

Method:        First, I will get all the 15 cress seeds and put them each in a separate planting pot with some soil. I will make sure to use the same amount of soil with each seed as the soil contains nutrients as well as the water. Then I will measure out a certain amount (100ml) of each water type and water the seeds accordingly. The difference in growth will be caused because some of the water types have better nutrients in e.g. the tap water has not been filtered or had many things removed from it which is why some people but it in filters, which a plant can use to grow than others. For example, salt water will probably have the smallest growth, if any, shown in its cress as if there is too much salt then the plant will not grow. The plant that grows the most over a certain period of time most probably has the best water. In order to make a fair test, I will make sure that the cress seeds are mixed randomly so that one pot doesn’t get better seeds than the rest, I will used a dry measuring cylinder for each pot so that there is no excess from previous watering. I will also make sure that there is always the same volume (50ml) of water for each seed. I will perform this experiment three times as to make sure of no special seeds and to make an average. I will measure the cress in mm every day. This way there will be the same amount of time between measurements. This experiment will be performed over a period of 11 days.

Results (in mm)

Conclusion        

From my results I have come to the conclusion that cress grows best in tap water and it doesn’t grow at all in salt water. This shows me that the minerals are not just provided from the water but also from the soil otherwise I assume that the mineral water would have grown the best cress as it has “the best nutrients”.

Evaluation        If I was to do this experiment again to get better results there are two things I would change. Firstly, I would have taken results over about a month to give the seeds a real chance to grow and so there may have been a bigger range of growth to compare the water types in. If there were a greater time to grow, maybe another water type would have shown the greater results instead of tap water. Secondly, I would have used more types of water as one of them may combine all the good things from each type of water to make really good water to grow cress in.