The Scientific Method of problem solving

A Poor Hypothesis

  (bio lab 015)   (bio lab 165)
The basic steps:

  1. State the problem - a problem can't be solved if it isn't understood.
  2. Form a hypothesis - a possible solution, formed after gathering information about the problem.
  3. Test the hypothesis - an experiment is an organized set of procedures performed to determine if the hypothesis solves the problem or not.
  4. Draw conclusions - In it's simplest form, the conclusion will be "yes" the hypothesis was correct, or "no" the hypothesis was not correct.


Click on each step for details.

Scientific theory - a generally accepted explanation of a concept or a broad explaination of a natural phenomena.

Scientific law or principle - a description of a natural phenomena that does not vary.

Experimental design:   (bio lab 305)   (bio lab 343)  

The foundation of any scientific investigation is its experimental design, a logical outline that guides the gathering and evaluation of information. It is the researcher's plan for testing the validity of a hypothesis. Much thought and hard work accompany the development of a hypothesis and experiments that will yield clear results. A scientist's ability to ask key questions and to formulate them into testable hypotheses may largely determine the success or failure of a given research project.

The very nature of some questions requires estimations or assumptions to be made. Whenever estimations or assumptions are part of the experimental design, they must be clearly stated and justified as part of the experiment. Any estimation is based on some type of data. The data must be shown as well as the calculations that lead to the final estimate. An assumption is based on some fact. Any assumptions that are key to the experimental design must be stated as well as the reason for starting with this assumption.

Three factors are essential for good experimental design:

Performing the experiment:

Reporting experimental results:


Use logic to solve these problems:

Problem #1 - Six girls were running a race. When the winner crossed the finish line, the following conditions existed List the order in which the girls were running when the winner crossed the finish line.

Problem #2 - Two students, a boy and a girl, are sitting on a bench. "I'm a girl", said the one with blond hair. "I'm a boy", said the one with black hair.

At least one of these students is lying. Which student has blond hair and which has black?

Problem #3 - A ship in a harbor has a rope ladder, with rungs three decimeters apart, hanging over the side. The bottom rung is resting on the surface of the water. An incoming tide is rising at a rate of 20 centimeters an hour.

At the rate of the incoming tide, how long will it take the first four rungs of the ladder to be covered with water?

Research Links:









Logic Problem #1









Logic Problem #2

The girl has black hair and the boy has blond hair.









Logic Problem #3

The rungs of the ladder will never be covered. The ship rises with the water.