Choosing A Science Project

After you have made your preliminary investigation and have prepared your outline, you are ready to begin your project. Projects are so numerous and diversified that it makes it very difficult for someone else to tell you exactly how to make your project. A project is an original piece of work, and this fails to be the case when others are guiding every move you make. Those who are working on experimental projects should follow the scientific method which will now be explained.
In all scientific experiments (or projects) only one factor of the experiment should be allowed to vary (change). Let us look at an example. Suppose that you're interested in growing tomatoes in your back yard and you ask Mr. Brown, your next door neighbor, to give you some advice in regard to what type of fertilizer to use for gaining the best results. Mr. Brown strongly advises the use of a commercial fertilizer (chemical type). That afternoon at the garden supply store you meet another neighbor who claims that steer manure is "the only" fertilizer to use for growing tomatoes. The salesman in the store tells you some like one type and others like the other type. Not being satisfied with this lack of decision, you decide to perform a controlled experiment to find out which is really better, or if both are the same. Although such an experiment is quite simple, it is nevertheless the basis of a good science project. Similar projects are being performed daily by real scientists.

Here is your plan:

1. You will plant 30 tomato seeds, all from the same packet of certified seeds that are fresh and packed by a reputable company.
2. Ten seeds from the packet will be planted in ten flower pots marked "steer manure."
3. Ten seeds from the packet will be planted in ten flower pots marked "commercial fertilizer."
4. Ten seeds from the packet will be planted in ten flower pots marked "no fertilizer."
5. All 30 pots will have the same soil.
6. All 30 pots will have the same amount of soil.
7. All 30 pots will be of the same size and shape.
8. All 30 pots will have the same location in your yard.
9. All 30 pots will get the same amount of water.
10. All 30 pots will be watered at the same time of day.
11. All 30 pots will receive the same kind of water. Usually no problem.
12. All 30 pots will receive the same amount of light and sunshine.
13. All 30 pots will have the seeds planted at the same depth.
14. All 30 pots will have the seeds planted in the same position.
15. The pots marked "steer manure" will each receive the same amount of steer manure each week on the same day.
16. The pots marked "commercial fertilizer" will each receive the same amount of commercial fertilizer each week at the same time the "steer manured" pots are fertilized.
17. The pots marked "no fertilizer" will receive no fertilizer at any time.

     You should notice that only one factor (part) in the experiment plan has been allowed to vary; that factor is the fertilizer. Now you can be reasonably sure that if one group of tomato plants grows differently from the other tow groups, the reason will be the type of fertilizer, or in the case of the "no fertilizer" group, the lack of fertilizer. Can you imagine what would happen to your experiment if you used seeds from different packets and different companies, planted the seeds at different depths, used different amounts of water, etc.? If you had all of those factors varying, you would not know what caused one tomato plant to grow better that the others; you would be asking yourself, "Was it the amount of water, or was it the depth of the seed, or was it the kind of seed?" You would never know exactly which factor was responsible for the results. As a matter of fact, it could have been a combination of factors, but which combination?
     In the experiment plan the fertilizer was the "variable factor," and all the other factors were called "control factors." The group of plants that receive no fertilizer would be referred to as the "control plants." Wouldn't it be interesting if those with no fertilizer grew the best? This could lead to another experiment, such as "Does Fertilizing Tomato Plants Before Sprouting Affect the Growth of the Plants?" It is possible to do this experiment with fewer than 30 plants. It should be understood, of course, that when more plants are used, the results will be more accurate.

     In the experiment, a graph should be kept for each plant in the experiment. Each graph should be of the same type and must be labeled to identify it with the correct plant that it represents. In the above experiment, there would therefore be 30 graphs. To make the job a little less laborious, you could record information on the graphs every other day, or even every third or forth day. Recording information is one of the most important jobs of the scientist; scientists rely on facts, not guesswork. Graph paper

can be purchased from a stationery store and is not expensive. It can, however, be made by the student. The illustration below shows three sample, miniature graphs.      The above information shows the necessity of the scientific method, and it should be understood that a good science student must continue to study, ask questions of qualified people, make charts and graphs, take photographs, and make further observations all through the course of making the project.    Graph A is a sample of an unmarked graph, with the vertical axis showing the growth in inches and the horizontal axis showing the days, number 1 being the day the seed was planted. In graph B the growth of the plant has been plotted for 23 days. You will notice that even though the horizontal axis is marked 1-3-5-&etc., a plot
     Mark could be used between the uneven days' notice the mark for the twelfth day. Also, fractions of an inch may be plotted on the vertical axis, on the third day you will notice the plant has grown one-half inch. Graph C shows how the curved line has been drawn to connect the dots on the graphs; thus showing in a very meaningful way, the growth of that particular tomato plant for that many days. Of course, these are only miniature graphs, and thus are incapable of showing the full growth pattern.

     Although the graphs were used to demonstrate the value and purpose of using such devices for a plant experiment, the student should realize that graphs and charts can and should be used in most projects, whether the project involves plants, animals, electricity, or chemicals. Graph A should show the increase in temperature on the vertical axis and the amount of electrical current on the horizontal axis in an electrical project. The uses of graphs and charts are numerous, and the student should make every effort to learn as much as he can about these visual devices. Your librarian could probably suggest some good books that tell and show all about graphs and charts.