1. 8/28/15 Today I will explain the steps to the scientific method
Warm Up-
What is the scientific method?

2. Scientific Method and Experimental Design
Physics:
Unit 1

3. Scientific Method What is the scientific method?
A way to answer questions about the world
Why do we use the scientific method?
Good way to organize ourselves
Common sense

4. Scientific Method Steps 1. Identify the problem or question
2. Gather information and make observations
3. Form a hypothesis
4. Test the hypothesis (experiment)
5. Analyze the data and form a conclusion

5. Scientific Method Hypothesis - Theory – Law – educated guess
can never truly prove correct
Theory –
well tested hypotheses about a topic
Law –
Hypothesis or theory that has been tested over and over and generally accepted as fact

6. 8/31/15 Today I will demonstrate the steps of the scientific method.
Warm Up –
Find your pulse on your wrist or your neck and see how many times it beats in 10 seconds.

7. 9/1/15 Today I will design a controlled experiment Warm Up –
Why do we use the scientific method?

8. Designing a Controlled Experiment
Experiments in science often try to figure out how one thing affects another thing.
Variable – any factor or “thing” in a scientific experiment

9. Designing a Controlled Experiment
When one variable is changed, the effect on the second variable can be measured.
You can only change ONE variable
- or else you won’t know where the response came from!

10. Designing a Controlled Experiment
Scientists always try to conduct controlled experiments.
This is done by choosing only one variable to change, and holding all other variables constant.

11. Designing a Controlled Experiment
Suppose you want to test how changing the mass of a pendulum affects the time it takes a pendulum to swing back and forth (also known as its period).

12. Designing a Controlled Experiment
You must keep all other variables constant, such as:
length of the pendulum string
distance the pendulum is pulled back
Controlled variables – variables not being tested that must be held constant

13. Designing a Controlled Experiment
The only thing you would deliberately change is the mass of the pendulum.
Independent variable – the variable that is deliberately changed in an experiment

14. Designing a Controlled Experiment
Since you are testing the effect of changing the mass on the period, the period is what you are testing for.
Dependent variable – the variable that responds to (or depends on) the deliberate change. This is what is measured.

15. Designing a Controlled Experiment
You can also further make sure that your results are valid by setting up a control group.
Control group – a group that does not change any variable to ensure variable is not affected by other influences.

16. Designing a Controlled Experiment
Controlled experiment – an experiment conducted with only one independent variable and only one dependent variable while holding all other variables constant.

17. Mythbusters – Talking to plants
Worksheet – scientific variable

18. 9/2/15
Today I will practice making helicopters and determine a good variable to test
Warm Up –
I want to see if using the air conditioner in my car really uses more gas. If I design an experiment to test this, what is the dependent variable and what is the independent variable?

19. Helicopter Experiment
Build a helicopter out of an index card using the example.
Cut on solid lines, Fold on dotted lines
Make a list of variables that can be changed and choose one!

20. 9/3/15 Today I will design an experiment to test helicopter flight
Warm Up –
I want to test how the newest exercise video works for weight loss, so I design an experiment. What is my independent variable, dependent variable, and control variables?

21. Data Table In a controlled experiment, we need to gather data!
Where will we put this data?
Data Table!

22. Data Table
Why do we need a data table?
-Organization
-Communication

23. Data Table Elements of a good data table:
Overall title – explain what is in the table
Column titles – explain what each piece means
Independent variable may be filled out in advance.

24. Data Table
Data Tables must be set up BEFORE you begin your experiment!
Data collected during the experiment is filled in as you go!
Let’s set up our helicopter table!

25. 9/4/15 Today I will finish my helicopter experiment
Warm Up – I have heard that oiling the wheels on my skateboard will make me go faster. What is the independent, dependent and control variables? How might you set up an experiment?

26. 9/8/15 Today I will graph data
Warm Up – I notice that the later it gets in the day, the more talkative my students are. What is my independent and dependent variable?

27. Revisiting Variables
In some cases, the independent and dependent variables are not very clear because you have not set up an experiment.
In this case, ask yourself: Does “a” depend on “b”, or does “b” depend on “a”?
I have more energy when I eat more food.

28. Graphing
Once the data is collected, it is necessary to determine the relationship between the two variables in the experiment.
For each relationship, we can make a graph!

29. Graphing Super important:
The independent variable is plotted on the horizontal or x-axis!
The dependent variable is plotted on the vertical or y-axis!

30. Elements of good graphs:
A title – describes the experiment.

31. Elements of good graphs:
Space and scale – the graph should fill up the entire space allotted and use an appropriate scale. Each square on a given axis must be the same scale, however, the x and y axes may be scaled differently.

32. Elements of good graphs:
Labels – each axis must be labeled with the variable and the unit of that variable.

33. Elements of good graphs:
Data Points – Each data point should be plotted and marked with a small dot. (Do not connect the dots)

34. Elements of good graphs:
Best fit line – this line should show the overall trend of the data. It should be a straight line, but does not necessarily have to touch each point. Does NOT need to go through the origin!

35. Best Fit Line

36. Best Fit Line

37. Graphing
Scale–
For many purposes, you do not have to start your scale at zero.
HOWEVER, because we will need to find the y-intercept on our graph, we must start at zero, even if that makes our graph weird!

38. Graphing Activity #1

39. 9/9/14 Today I will analyze graphs of data Warm Up –
In the equation y=mx + b, what does m and b stand for?

40. Graphical Analysis Slope:
Choose two points that fall on your best fit line that are easy to read.
These can be
1.) Actual data points that fall on your line or 2.) Points where the graph paper lines meet
These are (x1, y1) and (x2, y2). You must write these two points down.

41. (5, 5)
(10, 7)

42. Graphical Analysis
*Slope tells us the relationship between the variables. Every time the independent variable increases one, the dependent variable does what the slope says!

43. Graphical Analysis
Let’s find our slope! x1 y1
(5, 5)
(10, 7) y2 x2

44. Graphical Analysis
*Units on slope:

45. Graphical Analysis
y – intercept – The point on the graph where they line crosses the y-axis.
The y-intercept is the value of the dependent variable when the independent variable is zero.

46. Graphical Analysis Units on y-intercept = Unit on y-axis
Let’s find our y-intercept!
y-intercept = 3!

47. Graphical Analysis Equation of the line: y = mx + b
where m = slope and b = y-intercept
So, what is the equation of our line?

48. Graphing Activity #2

49. 9/10/15 Today I will graph and analyze data. Warm Up –
Explain what the slope means

50. 9/11/15 Today I will graph and analyze data. Warm Up –
Explain what the y-intercept means

51. Analyzing Data
We can use our graphs, to find information that we don’t have.
Find the given data on the graph and trace to the line, then trace to the corresponding value on the opposite axis.
(You may need to estimate.)

52. Analyzing Data Take out your “Halloween Candy” project.
If I go to 24 houses, how much candy can I expect to get?
If I received 92 pieces of candy, how many houses did I go to?

53. 9/14/15 Today I will graph and analyze data. Warm Up –
What is the equation for finding slope?

54. 9/15/15 Today I will graph and analyze data. Warm Up –
My eyesight gets worse with age. What is the independent variable?