The Scientific Method

5 Steps: Identify the Problem. Research the Problem. Form a Hypothesis. Test the Hypothesis. Draw Conclusions.

1. Identify the Problem What is your Goal? What Idea are you trying to test?

2. Research the Problem Examine Background Information about the problem. Aids in Developing a Hypothesis. Hypothesis = prediction about a phenomenon.

3. Form a Hypothesis Make a Prediction about the problem or goal you are investigating. Compose an “If….Then….” statement. Keep it Simple!

4. Test the Hypothesis Perform an Experiment by: Listing Materials you will need. Outlining a Procedure for the experiment. Identifying How you will Collect Data.

5. Draw Conclusions Ask yourself, “Was my hypothesis an accurate prediction?” Base your conclusions on your Experimental Data.

Types of Conclusions Hypothesis vs. Law vs. Theory Hypothesis - an educated guess based on previous experiences If I push a heavy object, it will move more slowly than if I were to push a lighter object. Connection to rolling spool: If Mr. Roth pulls the string to the left, the spool will roll to the … Source: http://www.m-w.com/dictionary/hypothesis

Law – A statement that is always true under given circumstances. Ex: The net external force on an object is equal to the product of the mass and the acceleration. Connection to rolling spool… The direction of motion will be in the direction of the greater force.

Theory - A set of tested hypotheses that give an explanation of a law. Ex: When we measure the mass of the objects and the acceleration of the objects, their products are equal indicating that with an equal force, a lighter object will have a greater acceleration than a heavier object. Connection to rolling spool: When we measure the friction between the table and the spool and the force Mr. Roth pulls the string, the force of Mr. Roth pulling is greater and that is why it moves to the Left.

Law vs. Theory A law summarizes what happens A theory (also can be called a model) is an attempt to explain why it happens. Look, Kid, I don’t know why. Ask him to explain it!

Keys to experimental design An example: Suppose you wanted to test whether a type of fertilizer really does make plants grow faster. When testing the hypothesis, how can you tell if your hypothesis is true or not? A control group is needed in order to make a comparison.

Types of Variables Independent variable: a variable that is deliberately changed or controlled by the experimenter Dependent variable: the quantity that changes as a result of the independent variable.

Types of Data Quantitative: The data is measured and given a numerical value based on the measurement. Examples: distance, height, weight, time, etc. Qualitative: The data is measured as part of a category Examples: Color, cleanliness, clarity, good or bad, etc.

Determine if the following are Quantitative or Qualitative The student’s eyes are blue The table feels smooth The food smelled delicious The height of the tree is 6 meters. The clock read 3:20 PM The apple tasted sour The temperature outside is 320F The baby weighed 8 pounds

How to graphically represent data Qualitative data: Use bar graphs, circle graphs, or tables/charts. Quantitative: Use a set of x and y axis.

Quantitative Graphing When graphing, the independent variable always goes on the x-axis. The dependent variable always goes on the y-axis.

Example Notice the elastic cords attached to Mr. Roth’s ceiling. The problem: How does the amount that the cord stretch depend on the weight added to the cord? Let’s do a full scientific method.

Identify the problem: Already done Research the problem: Give some background knowledge you know already about elastic cords related to the problem. Form a hypothesis:

Create a procedure for testing the hypothesis: What will be the control (comparison)? What is the independent variable? What is the dependent variable? What data will be collected and how will it be presented to make a conclusion?