The Scientific Method
By John Cowens

When scientists try to solve problems, they usually search for an answer in an orderly and systematic manner. Anyone who is inquisitive can be a scientist. All you have to do is answer questions by following a simple, logical and straightforward prescription that's called the scientific method. Sometimes, when using this method, problems are quickly solved. But they can also take many years to solve and sometimes a problem remains unsolved.

Encourage your students to utilize the scientific method throughout your investigations this year. By using this method you can be sure that you are carrying out science inquiry correctly. Here's a general description of scientific method and as well as a fun lesson that includes all of the inquiry components.

Just five steps
The scientific method has five steps:

1. Determine a scientific problem to solve or make an observation. This is a question you must have in your mind as to how or why something works or how something happens. A good example of stating a problem is "How does acid rain affect forests?"
2. Develop a hypothesis.
   This component is merely a good-quality speculation, a guess about how or why something happens. Generally, based on your hypothesis, you can predict the outcome for a particular experiment you perform.
3. Testing your hypothesis.
   Experiments need to be performed to test your hypothesis. In some cases, finding out your hypothesis is incorrect is just as good as finding out that it is correct! This step is important, as you must also check the results of your experiments against known facts.
4. Recording your observations.
   After conducting experiments, what did you find out?
5. Drawing a conclusion.
   This step presents your interpretation of the results of the experiments you performed. If your experiments match your original prediction, then they support your hypothesis. If not, you will need to explain why you think your prediction differed from your results. Were there problems while conducting the experiments? Perhaps you need a new hypothesis to explain what you see?

Proving yourself…wrong?
Scientific method is a very important objective process. Sometimes it's easy to look for information that already supports your "best guess." For example, let's say your project is called "In Which Habitat are Praying Mantises Most Likely to Live, Gardens or Fields?" If you have a garden at home, you watch a praying mantis in your garden. Unfortunately, your hypothesis will most likely state, "A praying mantis is most likely to live in a garden." Then, you take this one step further by recording only the data that shows praying mantises live in gardens and you ignore the information that shows that they live in fields. If this occurs, you are guilty of falling into the trap of favoritism – that is, a hypothesis you personally enjoy. However, good science requires that you search for whatever the answer is. Remember – proving your hypothesis wrong is just as valid as proving it right.

A prickly experiment
Here's a fun experiment to use with your students when demonstrating the scientific method.

QUESTION:
How is it possible for a person to lay on a bed of nails without becoming a "pincushion?" (Rather than allow students to lay on a bed of nails, let's substitute a balloon for a human being.)

HYPOTHESIS:
The closer together the nails are, the less pressure is applied on a person's body.

TESTING THE HYPOTHESIS:
Materials:

• cardboard box approximately 30 cm x 30 cm x 30 cm


• utility knife


• hammer


• 30 small nails (all the same length and width)


• four wood boards each 15 cm x 15 cm x 1.25 cm thick


• balloons (inflated about 12 cm in diameter)


• 1 bag of sugar


• one tablespoon


• 29 cm x 29 cm x 7 mm thick (any color) foam board


• foam bowl

Procedures:

1. Remove the top flaps of the cardboard box with a utility knife.
2. Hammer a nail completely through the center of one wood board so the head is pounded flat and the pointed end pokes out the other side. On the other three boards, pound in four, eight and 16 nails so they form a square pattern in the center area of the wood. The nails should be spaced about 1.25 cm apart from each other. Be sure that the pointed ends are the same height.
3. Place the board with one nail inside the box.

4. Trim the foam board so that it fits inside the cardboard box from side to side. It should rest flat like a shelf and barely graze the sides of the box.
5. Inflate a balloon to a diameter of 15 cm and set it lightly on top of the nail.
   Note: All balloons should have the same amount of air pressure. One simple method of doing this is to cut out a foam board circle with an inside diameter of 15 cm. Inflate the balloon until it can pass tightly through the ring.

6. Place the foam board on top of the balloon, then gently place the empty bowl on the center area of the foam board. In the picture below, the front panel of the box was removed to allow you to see inside the box – don't remove one side of your box.
7. Using a tablespoon, place the sugar in the foam bowl. Record how many tablespoons of sugar create enough weight to pop the balloon.

8. Empty the foam bowl, remove the popped balloon and replace the board containing one nail with a board holding four nails.
9. Place another inflated balloon on top of the four nails, place the foam board on top of the balloon and set the foam bowl on top.
10. Carefully add tablespoons of sugar to the bowl. Count the number of spoonfuls of sugar added to the bowl until the balloon pops. Did the balloon handle more weight this time?

11. Repeat steps 8-10, but use a board holding eight nails, then a board using 16 nails.
    Note: Be sure that the pointed tips of the nails are the same height or the balloon will "pop" where the nail protrudes above the others. Also, when using scientific method, it's important to repeat these experiments several times in order to establish consistent outcomes.

1. Make a bar graph. Across the bottom of the graph, enter the number of nails used in each experiment. On the vertical side of the graph, record the number of tablespoons of sugar placed into the bowl before the balloon was punctured.

CONCLUSION:
It's the force per unit area of skin (a.k.a. pressure) that determines if a nail will pierce the skin...or the balloon!

John Cowens teaches sixth grade at Fleming Middle School in Grants Pass, OR.