1. The Scientific Method

2. Vocabulary hypothesis independent variable dependent variable control
Methods of Scientists
Get your vocabulary sheet out!
Vocabulary
hypothesis
independent variable
dependent variable
control
Le Système International d’Unités (SI)
-Theory

4. The Nature of Scientific Investigations
Methods of Scientists
The Nature of Scientific Investigations
A scientific method is a planned, organized approach to solving a problem.
Once the problem is defined and research is complete, a hypothesis, or suggested explanation for an observation, is made.
Ex. IF I put 10 pounds of fertilizer on the grass, THEN the grass will grow better.

5. The Nature of Scientific Investigations
Experimentation
A hypothesis is tested by conducting an experiment, which is an organized procedure that involves making measurements and observations.
A good scientific experiment tests only one variable, or changeable factor, at a time.
The independent variable in an experiment is the factor that is manipulated by the experimenter.
A dependent variable is a factor that can change if the independent variable is changed.
A control is used to show that the results of an experiment are a result of the condition being tested.

6. What is a Variable?
A variable is any factor, trait, or condition that can exist in differing amounts or types.
Ex. Hypothesis: Fish live longer in COLD water.
What are some things (variables) we could change to test this?

7. Independent Variable
Something that can be manipulated by the experimenter.
Ex. Maybe instead of 10 pounds of fertilizer, I’ll use 50 pounds.

8. Dependent Variable
The result that is influenced by the independent variable.
Ex. WOW, with 50 pounds of fertilizer, the grass grew EVEN more!

9. The Control
The control in an experiment shows how the actual results differ from the treatment.
The control doesn’t change.

10. The Nature of Scientific Investigations
What is the independent variable in this picture?

11. Bart believes that mice exposed to microwaves will become extra strong(maybe he's been reading too much Radioactive Man). He decides to perform this experiment by placing 10 mice in a microwavefor 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8 out of 10 microwaved mice were able to push the block away. 7 out of 10 of the non-microwaved mice were able to do the same.
What is being tested?
What is the control group?
What is the experimental group?
What should Bart's conclusion be?

12. Krusty was told that a certain itching powder was the newest and best thing on the market; it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes.
What is being tested?
What is the control group?
What is the experimental group?
What should Krusty's conclusion be?

13. Measurement Time  ??? Seconds
Methods of Scientists
Most scientific studies and experiments use a standard system of metric units called Le Système International d’Unités, or SI for short.
SI is a modern version of the metric system based on a decimal system that uses the number 10 as the base unit.
Time  ??? Seconds
Length  not feet or inches but…Meters or Centimeters
Mass  ??? Kilogram
Area  ??? cm2
Temperature  Celsius

14. Communication
Scientists must share the results of their studies with other scientists (peers)
Publish findings in journals
Present their findings at scientific meetings
Scientists must be unbiased
Should not tamper with their data
Only publish & report tested & proven ideas
We will use Google Documents!

15. Theories
A theory may be formed after many related hypotheses have been tested and supported with experimental evidence, but it is not Law.
A broad and comprehensive statement of what is thought to be true
Supported by considerable evidence
Ties together related hypotheses
Theory of Plate Tectonics
Theory of Evolution
Theory of Natural Selection

16. Laws
A Statement of fact that concisely explains an action or group of actions e.g. Law of Gravity
Accepted to be true
Universal
May be expressed as a
math equation e.g. E=mc2
What does “C” stand for?