Why does a hypothesis must be testable

First it is crucial to base a hypothesis on careful observations. Faulty input when constructing an answer to a question will almost certainly lead to an incorrect answer. It is also important to define the problem clearly. Scientists try not to jump to conclusions. No matter how obvious the answer to a question might seem, it is still necessary to formulate and test a hypothesis. There is a tendency for hypotheses to become more complex than necessary. When seeking an answer to a question, the simplest solution is most likely to be the correct one, so simple hypotheses should be considered first.

Formulation of hypotheses is based on logic , but be forewarned that what seems logical is not necessarily true. This idea seemed logical at the time, since it explained why the sun rose in the east and set in the west each day.

It took years and the development of the telescope for this logical hypothesis to be disproved. Your dietician has told you that fruits and vegetables contain vitamin C and you have observed that your friends that eat many fruits and vegetables get fewer colds. You have also read an article in a medical journal that describes how vitamin C reduces throat and nose irritation.

So you formulate the hypothesis that consuming vitamin C decreases the risk of catching a cold. To arrive at the hypothesis you have used inductive reasoning. That is, you have combined a series of specific observations to discern a general principle. Your hypothesis is a good one, since it testable, falsifiable, and based on logic.

However, you will not know whether it is true or false until you test it. Experiments Experiments have been performed by scientists for several hundred years. This wood carving from the 18th century shows early biologists attempting to determine whether exposure to electricity affects the growth of plants or the activity of animals.

Experiments are considered to be the most rigorous way to test a specific hypothesis. The experimental method is usually preferred because it allows the scientist to control conditions under which a given phenomena takes place.

Manipulation of the environment of an experiment provides a way to minimize the number of alternate explanations for the data and increases the likelihood of arriving at the correct conclusion. In the experimental method of hypothesis testing, the experiment is divided into two parts. In one part, the subject of the experiment receives a treatment designed to elicit a response related to the hypothesis. The experimental control is handled identically, except that the treatment is not given.

If the treated and control groups differ, then the difference is probably due to the experimental treatment. In the example shown here, the scientist is trying to determine whether echinacea tea is an effective treatment for colds.

One group is given echinacea tea to drink for the next few days, whereas the other group the control is given colored water that only looks like tea. This is an attempt to make the two groups as similar as possible, so that the only difference in their attempts to get rid of the cold will be the consumption of echinacea.

The sham tea is called a placebo. That is it looks the same as the experimental tea and even has the same water content, but should have no effect on colds. People in the two groups did not know if they were given echinacea tea or the placebo.

This is important because just knowing that they are being medicated often causes patients feel better. So the scientist designing this experiment hopes that the only independent variable relative to cold severity is the echinacea compound. In this experiment, the patients that drank the real tea did report a bit more relief from cold symptoms than those in the control group.

So the scientist concluded that the tea was somewhat effective at relieving cold symptoms. However, one experiment is seldom enough to convince the scientific community that an effect is real. In the case of Echinacea tea, additional experiments have cast doubt on these results and it is still not known for sure whether drinking the tea is an effective cold treatment.

Bias A scientist using the experimental method must be careful that bias does not creep into the process. This can happen if the person performing the experiment has an opinion on what the result should be and unconsciously pushes the results in that direction. Formatting a testable hypothesis. What Is a Real Hypothesis? A hypothesis is a tentative statement that proposes a possible explanation to some phenomenon or event. A useful hypothesis is a testable statement, which may include a prediction.

A hypothesis should not be confused with a theory. Theories are general explanations based on a large amount of data. For example, the theory of evolution applies to all living things and is based on wide range of observations.

However, there are many things about evolution that are not fully understood such as gaps in the fossil record. Many hypotheses have been proposed and tested. When Are Hypotheses Used? The key word is testable. That is, you will perform a test of how two variables might be related. This is when you are doing a real experiment. You are testing variables. Usually, a hypothesis is based on some previous observation such as noticing that in November many trees undergo color changes in their leaves and the average daily temperatures are dropping.

Are these two events connected? Any laboratory procedure you follow without a hypothesis is really not an experiment. It is just an exercise or demonstration of what is already known. How Are Hypotheses Written? However, their form is not particularly useful. If these statements had not been written carefully, they may not have even been hypotheses at all. For example, if we say "Trees will change color when it gets cold.

Or if we write, "Ultraviolet light causes skin cancer. One way to prevent making such easy mistakes is to formalize the form of the hypothesis. Formalized Hypotheses example: If skin cancer is related to ultraviolet light , then people with a high exposure to uv light will have a higher frequency of skin cancer. If leaf color change is related to temperature , then exposing plants to low temperatures will result in changes in leaf color.

Notice that these statements contain the words , if and then. They are necessary in a formalized hypothesis. But not all if-then statements are hypotheses. A hypothesis or model is called falsifiable if it is possible to conceive of an experimental observation that disproves the idea in question. That is, one of the possible outcomes of the designed experiment must be an answer, that if obtained, would disprove the hypothesis.

The statement is intentionally vague. They may not. A good scientific hypothesis is the opposite of this.

If there is no experimental test to disprove the hypothesis, then it lies outside the realm of science. Scientists all too often generate hypotheses that cannot be tested by experiments whose results have the potential to show that the idea is false.

Science advances by conducting the experiments that could potentially disprove our hypotheses.