1. The Scientific Method
An Introduction

2. Nature of Science
“Science” is simply a logical way of thinking about the world.
Scientists use observations (with their senses) about the world around them in order to make inferences (logical guesses or predictions)
Science is always changing and growing as new information becomes known.

3. Observation versus Inference

4. Observations Any information collected with the senses.
The skill of describing scientific events
Quantitative – measurable or countable
3 meters long
4 marbles
50 kilograms
35 degrees Celsius
Qualitative – described with our senses, not measured
red flowers
smells like fresh baked cookies
tastes bitter

5. Inference
Conclusions, predictions, or deductions based on observations
The process of drawing a conclusion from given evidence
Practice:
You will close your eyes and quietly listen to 3 observations
After the observations have been shared, think of your inference.
Do not share your inference until asked to do so

6. Inference
Practice: Close your eyes and listen to the following observations: Inference?
I hear people screaming
I smell cotton candy, popcorn, and hamburgers
I see a lot of people

7. What was your inference & why?
Amusement Park
Share and Discuss
Day at the Beach
Sporting Event

8. Label Observation or Inference
__________Paul enjoys playing the guitar.
__________Sarah has a cold
__________Mr. Levin’s car has a big dent in it.
INFERENCE
OBSERVATION

9. There is a school dance tonight.
Observation practice
Write an observation for the following inference:
There is a school dance tonight.

10. The Scientific Method
The scientific method is a term used to describe the way in which scientists gather and use information.

11. We shall take a closer look at these steps and the terminology you will need to understand before you start a science project.

12. Steps of the Scientific Method
Step 1: State the Problem or Question based on observations that can be solved through experimentation.
Step 2: Gather information (research)
Step 3: Form a hypothesis
A hypothesis is an educated guess based on what you already know
Step 4: Test the hypothesis by making an experiment
Develop and follow a procedure. Include a detailed materials list. The outcome must be measurable (quantifiable)

13. Steps of the Scientific Method
Step 5: Collect & Analyze data
Include tables, graphs, and photographs
Step 6: Draw conclusions
Include a statement that accepts or rejects the hypothesis.
Make recommendations for further study and possible improvements to procedure.
Step 7: Share information with others (report your findings)
Be prepared to present the project to an audience.
Expect questions from the audience.

15. The Scientific Method You use the scientific method every day.
Example: You get home from school, put your key in the lock, and can’t open the door.
Here goes the scientific method…

16. The Scientific Method
State the problem/question: Why can’t I open the door?
Gather information: My key isn’t turning.
Hypothesis: I used the wrong key.
Experiment: Use a different key.
Collect data: Next key does turn in the lock.
Conclusion: Since the other key opens the door, I must have used the wrong key the first time.
Hypothesis supported.

17. Scientific Method
Describe one way you used the scientific method sometime this week. Don’t use the example provided
Share and discuss

18. Let’s put our knowledge of the Scientific Method to a realistic example that includes some of the terms you’ll be needing to use and understand.

19. She explains that yeast releases a gas as it feeds on sugar.
Problem/Question
John watches his grandmother bake bread. He ask his grandmother what makes the bread rise.
She explains that yeast releases a gas as it feeds on sugar.

20. Problem/Question
John wonders if the amount of sugar used in the recipe will affect the size of the bread loaf?

21. Caution!
Be careful how you use effect and affect. Effect is usually a noun and affect, a verb. “ The effect of sugar amounts on the rising of bread.” “How does sugar affect the rising of bread?”

22. Observation/Research
John researches the areas of baking and fermentation and tries to come up with a way to test his question.
He keeps all of his information on this topic in a journal.

23. John talks with his teacher and she gives him a Experimental Design Diagram to help him set up his investigation.

25. Formulate a Hypothesis
After talking with his teacher and conducting further research, he comes up with a hypothesis.
“If more sugar is added, then the bread will rise higher.”

26. Hypothesis It is written in an If, then statement
The hypothesis is an educated guess about the relationship between the independent and dependent variables.
It is written in an If, then statement
Note: These variables will be defined in the next few slides.

27. Do you know the difference between the independent and dependent variables?

28. Independent Variable
The independent, or manipulated variable, is a factor that’s intentionally changed by the experimenter.
John is going to use 25g., 50g., 100g., 250g., 500g. of sugar in his experiment.

29. In this case, it would be the size of the loaf of bread.
Dependent Variable
The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable.
In this case, it would be the size of the loaf of bread.

30. She discusses with John how to determine the control group.
Experiment
His teacher helps him come up with a procedure and list of needed materials.
She discusses with John how to determine the control group.

31. What is a controlled experiment?
A controlled experiment is a scientific test that is directly manipulated by a scientist, in order to test a single variable at a time.
Why is this important?

32. Control Group
In a scientific experiment, the control is the group that serves as the standard of comparison.
The control group may be a “no treatment" or an “experimenter selected” group.

33. All experiments should have a control group.
The control group is exposed to the same conditions as the experimental group, except for the variable being tested.
All experiments should have a control group.

34. Control Group
Because his grandmother always used 50g. of sugar in her recipe, John is going to use that amount in his control group.

35. Control Examples
Drug Test: Two groups of people get a pill. One group gets a pill that contains the new drug to be tested (the experimental group), and the other (the control group) gets a pill that does not contain the drug.

36. Control Examples
Engine Test: Two identical engines have different carburetors. One is a new fuel injected carburetor (the experimental group), and the other (the control group) is the standard carburetor.

37. Control Examples
Teaching Method: Two groups of students are taught algebra. One uses a new method (the experimental group), and the other (the control group) uses the old way.

38. Constants
John’s teacher reminds him to keep all other factors the same so that any observed changes in the bread can be attributed to the variation in the amount of sugar.

39. Constants
The constants in an experiment are all the factors that the experimenter attempts to keep the same.

40. Can you think of some constants for this experiment?

41. Constants They might include:
Other ingredients to the bread recipe, oven used, rise time, brand of ingredients, cooking time, type of pan used, air temperature and humidity where the bread was rising, oven temperature, age of the yeast…

42. Experiment
John writes out his procedure for his experiment along with a materials list in his journal. He has both of these checked by his teacher where she checks for any safety concerns.

43. John is going to test each sugar variable 3 times.
Repeated Trials
Trials refer to replicate groups that are exposed to the same conditions in an experiment.
John is going to test each sugar variable 3 times.

44. Collect and Analyze Results
John comes up with a table he can use to record his data.
John gets all his materials together and carries out his experiment.

45. Organize and Analyze the data
Create charts, graphs, or tables
These can help scientists see their results in an easily readable format
Data is divided into two categories:
1. Qualitative data: descriptions, words
2. Quantitative data: numbers, measurements

46. Size of Baked Bread (LxWxH) cm3
Size of Bread Loaf (cm3)
Trials
Amt. of Sugar (g.) 1 2 3
Average
Size (cm3) 25
768
744
761
758 50
1296
1188
1260
100
1080
1116
250
672
576
588
612
500
432
504
360
Control group

47. Collect and Analyze Results
John examines his data and notices that his control worked the best in this experiment, but not significantly better than 100g. of sugar.

48. Conclusion
John rejects his hypothesis, but decides to re-test using sugar amounts between 50g. and 100g.

49. Once again, John gathers his materials and carries out his experiment.
Here are the results.

50. Can you tell which group did the best?

51. Size of Baked Bread (LxWxH) cm3
Size of Bread Loaf (cm3)
Trials
Amt. of Sugar (g.) 1 2 3
Average
Size (cm3) 50
1296
1440
1344 60
1404
1380 70
1638
1560
1612 80
1332 90
1080
1200
972
1084
Control group

52. Graphing Independent variables go on the X axis
Dependent variables go on the Y axis

53. Conclusion John finds that 70g. of sugar produces the largest loaf.
His hypothesis is accepted.

54. Communicate the Results
John tells his grandmother about his findings and prepares to present his project in Science class.

55. Theories v. Laws
Theory= a hypothesis supported by many experiments (Scientific) Law= a theory that has never been disproved over a long period of time What scientific laws can you think of? Law of gravity Law of thermodynamics
Sir Isaac Newton

56. Your turn to practice… List the problem (in question format)
Independent Variable
Dependent Variable
3 Constants
Create a data table for the results data
Create a graph for the data provided