SBA skills – Planning and design H
‘A mind, when stretched by a new idea, never regains its original dimensions.’ – Anonymous ELLO AGAIN, students! How are you this week? Our quote above is one I wished that I had thought of first, because it is oh so true! The greater the stretching, the smarter we become, so keep acquiring those new ideas!
This week, we will continue our study of the requirements for your SBAs. We will do this by looking at the skill known as planning and design. This skill is a sore point for everyone, not just you! Teachers do not like it, because they have to help you to think of creative problem statements for you to work on; you students do not like it, because formulating hypothesis and writing up these experiments require too much thought; and, lastly, the examiners do not like it, because they get bored reading the same experiments year after year!
You are now required to plan an investigation in your fourthform/grade-10 year which you will have to carry out in your fifthform/grade 11 year. The actual planning of the investigation will be marked for P&D and the write-up of your investigation will be marked for analysis and interpretation in year 2.
Students, you are encouraged to look around you to see what is happening and to use examples of what you see as the basis on which you will formulate your hypotheses (note that this is the plural form of the word hypothesis).
What is a hypothesis, you may ask? This is a good question because many times this is the word that floors you! A hypothesis is an idea or explanation about how things work or why things happen that can be used as a starting point for an investigation. This idea is based on particular observations that can be tested by carrying out experiments. This means that you should be able to design an experiment, the results of which would support your question.
FORMULATING THE HYPOTHESIS
Here is a problem that a gardener noticed. He noticed that whenever he planted Impatiens (a flowering plant commonly known in Jamaica as Lady Slipper), they would soon die, but those planted by his neighbour survived for years. He noticed that while his plants were planted under the eaves of the verandah, his neighbour’s were planted under a spreading breadfruit tree.
Suggest a possible hypothesis for the gardener’s dilemma, then design an experiment which you could carry out to test your hypothesis.
POSSIBLE HYPOTHESIS
Impatiens grow best in areas that receive diffused sunlight. Impatiens planted in areas that receive continuous direct sunlight eventually die.
POSSIBLE AIM
To investigate the effect of direct sunlight on the survival of Impatiens.
ANOTHER OBSERVATION
While redesigning his garden, the gardener had to turn over some stones in order to move them and he noticed that there were many millipedes found under these stones. These animals were not seen anywhere else.
POSSIBLE HYPOTHESIS
Millipedes live in areas that are not affected by direct light.
POSSIBLE AIM
To investigate the effect of direct light on the distribution of millipedes.
ANOTHER OBSERVATION
It is observed that when green bananas are cooked with a slice of lime/lemon, neither the bananas nor the water in which they are cooked darkens. What do you think would be a suitable hypothesis formed from this observation? What do you think is preventing the darkening?
ANOTHER OBSERVATION
It is observed that when the periwinkle plant is not watered frequently, the leaves fold in such a way that the undersurface is not exposed.
Why do you think that this is so?
ANOTHER OBSERVATION
Tamara and Tracy had an argument at school one day. Tamara said that Barbados cherry had more vitamin C than star fruit (carambola), while Tracy was adamant it was the other way around. Who is correct?
DESIGNING THE EXPERIMENT
The experiment that you will design must have the following:
The hypothesis – This must clearly relate to the observation that was made, and must be stated in such a way that it can be tested. An aim – This must clearly relate to the hypothesis. A list of the apparatus and materials that you will use in carrying out your experiment. Try to avoid using words such as ‘some’, ‘a few’ and ‘many’. Be precise and use, instead, for example, 500g of soil, 200cm3 of water, 10 millipedes, etc.
A clear method. Unlike the other experiments that you have written, planning and design experiments are written in the present tense and not the past tense. This is because the experiment has not yet been done, so you are giving instructions as to how it must be carried out in your method. A suitable control must also be included. You should also include the number of repeats of the method that are to be carried out. Remember, repeats increase the validity of your experiment.
Identification of the different variables, the manipulated, the responding and the controlled. A summary of the expected results. Assumptions/Precautions/Possible source of errors – at least one of these must be stated.
If all of these criteria are met, you would have been successful in satisfying the requirements for this SBA skill. Remember, it is important to get a good grasp of the requirement for this skill because not only is it a requirement for the project in year 2, it often forms a part of Paper 02 of your written examination. Now go practise and practise, and practise some more! See you next week!