Tea Bean
My Bean has sprung into action! It is 2mm in height and very green. I have been feeding it tea for two days. It has grown towards the window because of the light. I will keep monitoring its height and colour.
Sugar solution bean
During the first few days of growth, the sugar solution appeared to facilitate the growth of the bean shoot (see graph for results), however as time continued, the sugar solution crystalised in the soil and the growth of the shoot slowed.
As you can see from the photos below, by Day 14, the shoot was limp and turning brown and you can see the sugar crystals on the surface of the soil.
Results – Control bean (water)
Above is a record of the control bean’s growth. As we can see, when the bean was watered regularly with normal tap water, it’s growth was rapid and steady. The bean grew straight and tall. It was healthy with green leaves. This bean, as predicted,grew taller than the other beans watered with tea, salt and sugar. It kept growing even after I stopped watering it, which indicated that normal water is very conducive to a bean’s healthy growth.
Results – Tea Bean
These are the results from my tea bean. Its growth started off very slowly compared to the bean being watered with normal tap water. On the fourth day when it reached 14.6mm the steam looked a dirty brown colour. Over the next few days it got progressively darker and then turned black. This was the effect of feeding the bean black tea. You can see the tea colour slowly rising up the stem and in the last few days the leaves started to turn a brownish colour.
The bean started out as quite strong as it was receiving water before it had germinated. The tea mix was quite strong and it started to poison the bean after the fourth day. The bean became weak and bent and struggled to grow straight.
As the graph shows the bean grew steadily up until the 11th day. It then did not grow any more before it turned black and died. It did not grow any more because the tea was too concentrated and poisoned the bean.
Results – Sugar solution
As this graph shows, growth of the bean shoot was steady until Day 6, where a growth spurt occured, the bean increasing in length from 35mm to 68mm. This rapid growth occured until Day 8 where at 110mm, the bean slowed its growth.
By Day 14, having reached 130mm, the shoot was beginning to turn brown, its leaves undernorished and the steam to become limp. It is possible that the crystalised sugar was preventing the nutrients in the soil from being absorbed by the roots.
A reason for the beans growing tall and healthy initially with the sugar solution might be because the plant gained an increase of glucose which is needed for photosynthesis. However by the 8th day, there was perhaps an excess of sugar which prevented the plant from gaining sufficient water.
Results – Salt Solution
This is a graph to show the growth results of the salt bean. To begin with, the salt bean grew steadily as with any other liquid, and after about a week and a half had reached around 40mm. However, at this point the bean stopped growing any more. At the end of two weeks, the bean was begining to show dark spots on the tips of the leaves where the cells had died. Even though we only measured the bean for two weeks, I contuinued to monitor the effects of the salt solution over a longer period of time, and watched as the bean shoot gradually turned entirely black and died.
If we were to run the experiment again I would suggest a longer time span so that this could be included in our measurements and on this graph.
Results – overall
As can been seen from the graph above, the most successful growth of the broad bean occured in the control group, where water was used. The sugar solution was the second most successful growth, however as explained in the results section above, its growth was not very healthy by the end of the 14 day period, as the stem became brown.
Both the salt and the tea solution had a damaging effect on the broad beans’ growth and neither grew many millimetres over the 14 day period, compared to the control bean. As seen in the graph, the salt solution affected the growth of the broad bean the most compared to all other solutions.
Conclusion
In conclusion, the best solution to use when growing a bean is water. The other solutions all ultimately had a negative effect on the bean’s rate of growth and heath.This could be for the following reasons:
- Salt dehydrated, and therefore takes away the water from the plant cells where it is needed.
- Tea contains caffeine which is a toxin, and collects in the plant cells. Furthermore tea is acidic, and for many plants this will damage growth and health.
- Sugar may have had an initial benefit for the young plant’s growth, but the mature plant can make sugar through photosynthesis and so too much sugar saturates the plant and stops it from being able to absorb water through the roots.
Evaluation of the experiment
Was it a fair test?
We felt that our test was mostly fair. We made sure that we each used the same type of beans, the same type and amount of soil, the same amount of water (or tea) in the same time intervals, and the same amount of solute (salt and sugar). We tried to keep the beans in the same kind of areas (e.g. by a window, away from a radiator and in sunlight), however because the beans were in different houses the temperatures of each room might have been different, as was the amount of sunlight exposure.
What would we change if we did the experiment again?
Because we would conduct the experiment in a classroom, we could keep all the beans in the same place. We would also be able to water them at the same time each day to ensure consistency. We could expand our experiment by using other beverages, such as coca-cola, coffee and orange juice to get a broader picture.
