Characteristics of a science experiment

Answer 1

In a science experiment, the effect of an independent variable on a dependent variable is tested. The variables can be any measurable quantity. Experiments usually include a control group, a group where the level of the independent variable is "normal". All factors are kept the same for each of the runs, except for the independent variable. These unchanging factors are called "constants". The scientist usually starts with a hypothesis, what they believe is going to happen.

For example consider the following experiment:

A scientist wants to find the effect that Ammonia will have on the height of plants. So he sets aside several different plots of land, and places different ammounts of ammonia on each plot (measured in mass). Except for the amount of Ammonia, the conditions of each plot are exactly the same. They are given the same amount of water, sunlight, heat, type of plant, ect.

The scientist records the height of each of the plants regularly, maybe every week. At the end of the experiment, all of the data is compiled, and a graph is usually made. Most rigorous experiments will include several runs to see if the results can be duplicated. The hypothesis is modified to fit the results of the experiment.