Scientific Method

Forming a hypothesis is the first step of the scientific method.

A scientific law is different from a scientific theory because it describes something in nature without attempting to explain it.

In order for a hypothesis to be testable, scientists need to be able to carry out investigations that will either support or disprove.

The experimental group is the group that is left alone during the experiment.

The manipulated variable is the same thing as the independent variable.

A company wants to test a new dog food that is supposed to help overweight dogs lose weight. 50 dogs are chosen to get the new food, and 50 more dogs continue their normal diets. After one month, the dogs are check to see if they lost any weight.

A new sunscreen has been developed that is supposed to be more effective at preventing sunburn. 30 participants spray one arm with the new sunscreen, and spray the other orm with the old sunscreen. After 4 hours in the sun, their skin is evaluated for any redness.

A student wants to study the effect of sunlight on plant growth. In his experiment, 12 plants receive normal amounts of sunlight, but half of them are kept uder bright sun lamps all night long. After 6 weeks, the plants' heights are measured.