| One of the key ingredients to most Science Fair | | | | worse because it was a weaker or younger plant |
| Projects is the experiment. The experiment is what | | | | than the others. If the ‘Brand A’ subject grows |
| tests your hypothesis. Your goal will be to create an | | | | the best in all three sets, then it will solidify the results |
| experiment that allows you to test different variable on | | | | that it truly is the better option. If one does well and the |
| the same situation. It would be difficult to explain this | | | | other two do not, then it is likely that the ‘Brand |
| process without an example, so we will create an | | | | A’ was not the determining factor for the growth in |
| experiment to use throughout the entire article. Our | | | | the good one. This technique will also provide as a |
| experiment will involve testing plant grow with various | | | | backup in case of contamination or error. If you have |
| fertilizers. | | | | only one set and it gets ruined (gets knocked over by |
| The first thing that we | | | | pet, sibling, etc) then you will have to start all over, and |
| must establish is that a control is necessary. A control | | | | that’s even if you are able to due to project |
| is simply one subject (plant in our case) that will not be | | | | deadlines. If you have multiple sets, one can be thrown |
| exposed to any variables. Let say that we want to | | | | out without scrapping the project. |
| compare plant growth using these fertilizers: Brand A, | | | | The key in every experiment is to set it up so that only |
| Brand B, soil from a compost pile, and soil with manure. | | | | one variable is changed among the subjects and that |
| We have one variable, the fertilizer, and four test | | | | all other remain the same for each. In our example of |
| options. The control will be a fifth plant that has no | | | | testing fertilizer, we want to make sure that the type |
| fertilizer added to the soil. The control will give us an | | | | of soil, the amount of sunlight, the amount of water and |
| idea of the plant growth without the applied variable to | | | | the temperature are all the same very every subject. |
| compare to. For example, if three of our four plants do | | | | Not doing so could throw off your results by having |
| very poorly and our variable does not, then it is likely | | | | multiple variable affecting the growth of the plants. |
| that it was the variable applied to those three samples | | | | Then you would not know which variable was the |
| that caused the poor growth. However, if we have the | | | | cause of growth (or lack of). |
| same situation and the control also does poorly, then | | | | As your experiment progresses, you will want to keep |
| there is a greater possibility that there was something | | | | accurate records. In our example for plant growth with |
| else (other than the variable) that caused the poor | | | | fertilizers, you will want to check the plant height, width, |
| growth. Examples might include a bad batch of plants | | | | color and other features on a regular basis. It would be |
| from the start or that the plants became contaminated | | | | best to use the same measuring tool each time, |
| before or during the experiment. | | | | measure on a regular schedule (everyday, every other |
| Another factor that will | | | | day, etc) and measure at the same time every time. |
| guarantee better results is multiplying your test | | | | Measuring at different times throughout the day may |
| subjects. In the experiment listed above, we will have | | | | give incorrect readings because of how much sun light |
| five plants (four variables & one control). If you | | | | is getting to plant. Remember that the key is to make |
| created multiple sets, let’s say three, of the five | | | | sure that everything is as similar as possible with all |
| plants, then we will gain better results. With multiple | | | | subjects except for the one variable that you want to |
| sets, we will be more likely to rule out if one subject did | | | | change, the one you are testing. |