1. The Scientific Method

2. Hypothesis
An informed guess that tries to explain how or why an event occurs.
A suggested solution to a problem based on background knowledge.
A good hypothesis explains known facts.
It must be testable.
Written as an “If, then, because” statement.
What is one hypothesis that explains the origins of the galaxies?

3. The Big Bang Theory!

4. Big Bang Hypothesis
Originally the universe was packed into one dense sphere of hydrogen, probably not much larger than our sun.
About 15 billion years ago this mass of hydrogen exploded, forming a gigantic expanding cloud.
Some parts of the cloud moved faster than others, but all parts moved outwards, away from the center.

5. Big Bang (cont.)
As the clouds moved, the particles condensed into billions of galaxies.
They all continued to move outward, away from the center and each other.
Those moving at the fastest speeds are now farthest out in space.

6. What force caused the particles to condense?
Gravity!

7. Gravity
The force of gravity is directly related to the mass of the objects and how close they are to each other.
Mass – the amount of matter (stuff) in an object or substance.
Weight – the effect of gravity on an object or substance.

8. Steps in the Scientific Method
Identify the Problem/ Ask a question
What am I trying to figure out?
Make Observations
Gather Information
Find out what is already known by research and observation
Form a Hypothesis
Propose a solution based on your information
An educated guess about the relationship between the variables you will be testing

9. Observations Observations are factual statements, not opinions.
Gathered using your five senses.

10. Inferences Do the Farside activity!!
A possible explanation based on your observations.
Do the Farside activity!!

11. Design and Perform a Controlled Experiment or Collect Field Data
Develop a procedure to test your hypothesis.
A good or “valid” experiment will only have ONE variable! –its called a FAIR TEST or a CONTROLLED EXPERIMENT

12. Scientific Experiments Follow Rules
An experimenter changes one factor and observes or measures what happens.
The experimenter makes a special effort to keep other factors constant so that they will not effect the outcome.
Constants – all factors that remain the same and have a fixed value in an experiment.

13. Controls Controls are NOT being tested
Control - a duplicate setup of the experiment you are performing with everything identical except for the variable that you are testing
Controls are NOT being tested
Controls are used for COMPARISON

14. Variables Variables are factors that change.
Factor in the experiment that is being tested
Independent Variable – the variable that is purposefully changed by the experimenter
Dependent Variable – the variable that responds to the change (the outcome). It is measured or observed.

15. Confounding Variable
Confounding variable – variables that the researcher failed to control, or eliminate, damaging the validity of an experiment

16. Analyze Results The data is the results of the experiment
May be qualitative or quantitative

17. DATA
Must be organized
Can be organized into charts, tables, or graphs

18. DATA Precision – how close the measured values are to each other
Accuracy – how close the value is to the true value
Precision – how close the measured values are to each other

20. Conclusions Based on your data
Do your results support or reject your hypothesis?

21. Repeat
Repeat
Repeat

22. Communicate Results Theory – an explanation supported by much evidence
Law – statements that describe how the natural world works. No exceptions have been found

23. Perform a Controlled Experiment or Collect Field Data
Information from experiments, measurement, research and observation

24. Form a Conclusion Propose a Theory Test Publish your Results
Based on your results
Propose a Theory
Accepted hypothesis based on evidence
Test
Again and again
Publish your Results
So that others may verify your results