The Nature of Science Chapter 1

Section 1 What is Science? You should know this by now!!!

What is Science? A.Science —a way or a process used to investigate what is happening around you 1. Scientists observe, investigate, and experiment to find answers. 2. Scientists also use prior experience to predict what will occur in investigations. 3. Technology is the application of science to make products or tools that people can use.

What is Science? B. Communication in science 1. Thousands of scientific journals and magazines report the results and conclusions of experiments every year. 2. In grade 7 we will be using lab reports to communicate our findings.

Section 2 Doing Science I promise, it won’t hurt a bit!

Using the Scientific Method What is the Scientific Method? - steps to follow to solve problems - answers a scientific question by making observations about the question - creates controlled situations to eliminate bias

How do we eliminate bias? Determine the variables in the experiment! A variable is something that can change and influences a scientific investigation. TYPES OF VARIABLES a. Independent Variable- the factor that is changed. (You can only test one at a time!) b. Dependent Variable- the factor that is being measured. c. Constants - the factor that stays the same.

Outline of the Scientific Method 1. State the research objective. 2. Form a hypothesis. 3. Describe the research design, or how you will carry out your investigation. - Carefully choose and control the variables in the experiment 4. Select the best materials for the investigation.

Outline of the Scientific Method 5. Plan how to record your results, including what data tables you will use. 6. Analyze your data and figure out what your results mean. 7. Make conclusions. Don’t fall asleep on me yet!!!

Writing a Hypothesis A hypothesis must contain the words IF and THEN. –If I study for a test, then I will get an A. –If I eat a lot of sugar, then I will get hyper. –If I mix chemical A and chemical B, then they will create a new chemical.

Sample Size The more subjects you test, the more accurate your results. –For 8 th grade experiments, using 10 or more test subjects could be enough. –Scientists must use many more test subjects in order to test their hypothesis.

A hypothesis is….. IMPORTANT Even if it is not SUPPORTED.

Now you’re done taking notes… BUT……

Let’s try a problem… Bart thinks that drinking a 32 ounce Mountain Dew before you go skateboarding will help you do a higher ollie in the air. He divides 10 of his friends into 2 groups. To group A, he gives each person a 32 ounce Mountain Dew. To group B he gives nothing. Group A’s average ollie height was 2 feet, and group B’s average ollie height was 1 foot.

What is the problem being solved? Does mountain Dew make you do higher ollies on a skateboard?

What is the hypothesis? If you drink Mountain Dew, then you will do higher ollies.

What is the control group? Group B

What is the independent variable? Mountain Dew

What is the dependent variable? Ollie height

Is the sample size big enough? For a small experiment, yes. For accuracy, however, more participants would be better.

What is his experimental procedure? He divides 10 friends into 2 groups. Group A get Mountain Dew and Group B does not.

What should Bart’s conclusion be? Mountain Dew does cause you to do higher ollies.

Let’s try one more… And you in the front row……quit eating glue!

Last problem…. Homer thinks that adding hot sauce to gasoline will make a car go faster. One day, he adds hot sauce to Marge’s gasoline tank but no hot sauce to his own tank. They both drive to the same grocery store. It takes Homer 25 minutes to get there and Marge 20 minutes to get there.

What is the problem being solved? Does hot sauce make a car go faster?

What is the hypothesis? IF you add hot sauce to gasoline, THEN it will make your car go faster.

What is the control group? Homer’s car

What is the independent variable? Hot Sauce

What is the dependent variable? How long it takes to get to the grocery store.

Is the sample size big enough? Two cars is definitely not a big enough sample size.

What is his experimental procedure? Add hot sauce to one car’s gasoline tank but not to the other and see who gets to the grocery store first.

What should Homer’s conclusion be? He might conclude that hot sauce does make a car go faster, but his sample size was not big enough to make a conclusion

Think you’re ready to try some on your own now….?