1. What should you do if you see a fire in the lab?
Warm-up
What should you do if you see a fire in the lab?

2. Unit 1a: The scientific method
Or, never say, “I have a theory!”

3. The scientific method
Pattern of logical investigation involving stating a problem, forming a hypothesis, researching and gathering information, testing a hypothesis, analyzing data, drawing conclusions.
A way of thinking
Not restricted to science
Can’t use the scientific method for everything

4. hypothesis
A testable, possible explanation for a problem using what is known and what is observed.
An untestable hypothesis = a BAD hypothesis
Example: “I think this electronic box on the wall controls the room temperature”

5. Good or Bad hypothesis?
Love is the most important thing in the universe.
Love is claimed by most people to be the most important thing in the universe.
Chocolate is the best tasting substance in the world.
People exposed to chocolate in their culture are more likely to enjoy it.
Bananas outperform Gatorade as a recovery food/drink after a marathon.
Before the universe existed, there was a giant walrus whose consciousness was the only thing that existed.

6. experiment
Organized procedure for testing a hypothesis; tests the effect of one thing on another under controlled conditions

7. variable
Quantity that can have more one value. Can change in an experiment.
Examples: thermostat settings, room temperature, humidity, etc.
OFF
65°
85°

8. Dependent variable
Factor that changes as a result of changes in other variables
Example: the temperature of the room
72°

9. Independent variable
Factor that, as it changes, affects the measure of another variable
Usually what you manipulate
Example: thermostat setting

10. Graphing variables Use “DRY MIX” to remember
D: Dependent M: Manipulated
R: Responds I: Independent
Y: Y-axis X: X-axis
Set temperature
Actual temperature

11. constant In an experiment, the variable that does not change
Example: humidity, size of room. Size of AC unit.
Room 1
Room 2

12. control Standard used for comparison of test results in an experiment.
Example: room with no thermostat.
Room 1
Room 2

13. bias
Occurs when a scientist’s expectations change how the results of an experiment are measured or viewed.
Example: scientist subconsciously ignores or exaggerates data

14. model
Used to represent an idea object, or event that is too big, too small, too complex, or too dangerous to observe or test directly.
Example: a circuit diagram of the thermostat or a computer simulation of a thermostat controlling the temp.

15. Scientific theory
Explanation of things or events based on knowledge gained from many observations, investigations, and experiments.
A theory is NOT a hunch!!!
Explains the how or the why.

16. Scientific law
Statement about what happens in nature that seems to be always true under certain conditions; does not explain why or how something happens.
Examples: the law of gravity versus the theory of gravity.

17. Theories DO NOT become laws!
Laws are not “better” than theories

18. GRAPHICAL REPRESENTATION OF DATA
How to make your data speak, and how to read it

19. Cartesian plots Remember “DRY MIX”: X-axis: maniupulated, independent
Y-axis: responding, dependent, what is measured

20. Line graphs Data points are connected by lines
Used for many data points of continuous data (often time) on the x-axis

21. Line graphs

22. Bar graphs
data point magnitude on y-axis represented as vertical bar/line
Used for plotting non-continuous data, or continuous data with few data points, on x-axis, such as ice cream flavors, brands of shoes, color of light, seasons of year
Sometimes a bar graph or a line graph could be used to represent the same data

23. Bar graphs

24. Bar graphs

25. histograms
special line/bar graphs where y-axis represents the frequency of a measure (how common something is)
Frequency can be represented as number, fraction, percentage, proportion
Usually dependent variable values are put on the y- axis, but here the frequency of values (or a range of values) is placed on the y-axis. [“DRY MIX “does NOT apply]
Typically there is no space between the bars
Examples: IQ chart, height of people in population, grades on an exam, lifespan, “bell curve”

26. histograms

27. histograms

28. histograms