On Saturday the 12th of May, Mark Horner and I assisted in judging the Cape Town mini-expo for young scientists (http://www.expo.wcape.school.za/). This event serves as a prelude to the regional expo (Cape Town expo for young scientists) that will be held in August. This event gives learners who have never taken part in an expo the opportunity to see what it is all about and to receive feedback on how their projects are progressing.
For many learners participating, the expo is their first chance to do real science that fascinates them and often goes outside the borders of the school curriculum. Learners get a chance to learn about the scientific method and how to write up and present a science project.
There are many categories that learners can take part in, from, social sciences to technology,physics and chemistry. (http://www.expo.wcape.school.za/html/categories.html) . At this point the projects were all in their early stages. Learners had chosen many fascinating topics including: “Does a woman cut her hair when she is going through a big change in her life”; “Magnetized water on plants”; “Attracting birds to your garden”; “Insulation in informal houses”; and “Chemiluminescence”.
One of the consistent issues that we noted was that learners are not very familiar with the scientific method or the experimentation process. Although this method does not easily apply to technology projects, it applies in various forms and guises to non-technology projects. For this reason we have decided to produce a brief guide of the scientific method for learners.
When a scientist performs experiments the following process is followed:
For example: you observe that there is a spring tide (a high tide that is higher than normal) around full moon. You think about this and decide to test whether this is really true or not. Your hypothesis is that a full moon influences a spring tide. To test this you would place markers at the seas edge at each high tide and observe if the tide is higher at full moon. You would repeat this experiment several times, perhaps on different beaches. Your conclusion could be that there is a link between spring tides and full moon.
One very important point in designing your experiment is the variables. The following are needed:
- Choose some constant or control variable to base your measurements on. Every experiment depends on many factors, most of which you will take to be constant. In our example other factors would be the time of year, the influence of the sun, the type of beach chosen and the geographic location. A control variable would be the sea level between high and low tide.
- Decide what the independent variable is. This is the variable you are changing or that is being changed. The independent variable would be the phase of the moon.
- Decide what the dependent variable is. This is the variable that provides a measure of the independent variable. The dependent variable would be the height of the tide.
At the end of an experiment you must always check that you have answered the question that you posed. You also need to decide whether you have proved or disproved your original idea. During the experimental process you will likely go through several iterations of the intermediate steps, each time refining your experiment and coming up with better ways to carry it out.
Some very important points to note:
- Your experiment must be reproducible. Any one seeing your experiment should be able to reproduce it and get similar results.
- Your method should include sufficient detail so that someone else can follow it and repeat your experiment.
- Your hypothesis must be falsifiable. This means that your hypothesis should be able to be proven false.
While doing your experiment keep detailed notes about what you do, what measurements you take and the conditions in which you do the work (is it warm or cold, is it day or night, is it winter or summer). The conditions in which you work can have an effect on the outcome of your experiment. You must note all the details about the factors that you have decided are constant in your experiment.
Once this is done you can write up your experiment. Your experiment should have:
- An introduction – Why is this work being done? What background information did you gather?
- An aim – The question and hypothesis combined into one statement. In the example given this would be: “To determine if the full moon influences the tide.”
- A list of apparatus – This is part of the experiment design. For the example given this could be: sticks, metre sticks or tape measures.
- A method – This is part of the experiment design. The method must be detailed enough for any one to follow. This is often presented as a step-by-step list.
- A results section – This is the section in which you analyse and present your data . You can present your data neatly in tables, graphs and equations, as appropriate. For the example given, a table of sea levels and a bar graph of sea level would be most appropriate. You should also explain what the tables and graphs mean.
- A discussion section – This is the section in which you draw conclusions. You should look at your results and decide what they mean. Discuss all your results, any difficulties in the experiment, anything that went right or wrong that may have affected your results and start drawing conclusions based on your results.
- A conclusion section – This is where you present your conclusion. This must be linked back to your aim and original question. In the example given this would be: “It was found that the moon has an effect on the height of the tide. A full moon was often associated with spring tides.”
- Future work – A paragraph or two detailing what more can be done from following on from this experiment.
- Bibliography – List all the sources of information that you used.