For instance, if you want to do an experiment on agricultural fertilizer, don’t seek to answer the question, “Which kind of fertilizer is best for growing plants?” There are many different types of fertilizer and many different kinds of plants in the world - one experiment won’t be able to draw universal conclusions about either. A much better question to design an experiment around would be “What concentration of nitrogen in fertilizer produces the largest corn crops?” Modern scientific knowledge is very, very vast. If you intend to do serious scientific research, research your topic extensively before you even begin to plan your experiment. Have past experiments answered the question you want your experiment to study? If so, is there a way to adjust your topic so that it addresses questions left unanswered by existing research?
For instance, in our fertilizer experiment example, our scientist would grow multiple corn crops in soil supplemented with fertilizers whose nitrogen concentration differs. He would give each corn crop the exact same amount of fertilizer. He would make sure the chemical composition of his fertilizers used did not differ in some way besides its nitrogen concentration - for instance, he would not use a fertilizer with a higher concentration of magnesium for one of his corn crops. He would also grow the exact same number and species of corn crops at the same time and in the same type of soil in each replication of his experiment.
For instance, in our fertilizer experiment example, our scientist would grow multiple corn crops in soil supplemented with fertilizers whose nitrogen concentration differs. He would give each corn crop the exact same amount of fertilizer. He would make sure the chemical composition of his fertilizers used did not differ in some way besides its nitrogen concentration - for instance, he would not use a fertilizer with a higher concentration of magnesium for one of his corn crops. He would also grow the exact same number and species of corn crops at the same time and in the same type of soil in each replication of his experiment.
For instance, in our fertilizer experiment example, our scientist would grow multiple corn crops in soil supplemented with fertilizers whose nitrogen concentration differs. He would give each corn crop the exact same amount of fertilizer. He would make sure the chemical composition of his fertilizers used did not differ in some way besides its nitrogen concentration - for instance, he would not use a fertilizer with a higher concentration of magnesium for one of his corn crops. He would also grow the exact same number and species of corn crops at the same time and in the same type of soil in each replication of his experiment.
Typically, a hypothesis is expressed as a quantitative declarative sentence. A hypothesis also takes into account the ways that the experimental parameters will be measured. A good hypothesis for our fertilizer example is: “Corn crops supplemented with 1 pound of nitrogen per bushel will result in a greater yield mass than equivalent corn crops grown with differing nitrogen supplements. "
Timing is incredibly important, so stick to your plan as close as possible. That way, if you see changes in your results, you can rule out different time constraints as the cause of the change. Making a data table beforehand is a great idea - you’ll be able to simply insert your data values into the table as you record them. Know the difference between your dependent and independent variables. An independent variable is a variable that you change and a dependent variable is the one affected by the independent variable. In our example, “nitrogen content” is the independent variable, and “yield (in kg)” is the dependent variable. A basic table will have columns for both variables as they change over time.
Good experimental design incorporates what’s known as a control. One of your experimental replications should not include the variable you’re testing for at all. In our fertilizer example, we’ll include one corn crop which receives a fertilizer with no nitrogen in it. This will be our control - it will be the baseline against which we’ll measure the growth of our other corn crops. [4] X Research source Observe any and all safety measures associated with hazardous materials or processes in your experiment. [5] X Research source
It’s always a good idea to represent your data visually if you can. Plot data points on a graph and express trends with a line or curve of best fit. This will help you (and anyone else who sees the graph) visualize patterns in the data. For most basic experiments, the independent variable is represented on the horizontal x axis and the dependent variable is on the vertical y axis.
To share your results, write a comprehensive scientific paper. Knowing how to write a scientific paper is a useful skill - the results of most new research must be written and published according to a specific format, often dictated by the style guide for a relevant, peer-reviewed academic journal.
In this case, the type of aerosol fuel we use is the independent variable (the variable we change), while the range of the projectile is the dependent variable. Things to consider for this experiment - is there a way to ensure each potato projectile has the same weight? Is there a way to administer the same amount of aerosol fuel for each firing? Both of these can potentially affect the range of the gun. Weigh each projectile beforehand and fuel each shot with the same amount of aerosol spray.
Let’s also create our data table beforehand. We’ll have five vertical columns: The furthest-left column will be labeled “Trial #. " The cells in this column will simply contain the numbers 1-10, signifying each firing attempt. The following four columns will be labeled with the names of the aerosol sprays we’re using in our experiment. The ten cells beneath each column header will contain the range (in meters) of each firing attempt. Below the four columns for each fuel, leave a space to write the average value of the ranges.
Like many experiments, our experiment has certain safety concerns we need to observe. The aerosol fuels we’re using are flammable - we should be sure to close the potato gun’s firing cap securely and to wear heavy gloves while igniting the fuel. To avoid accidental injuries from the projectiles, we should also make sure that we (and any observers) are standing to the side of the gun as it fires - not in front of it or behind it.
We can even share our results with the world in the form of a scientific paper - given the subject matter of our experiment, it may be more appropriate to present this information in the form of a tri-fold science fair display.
