1. The Scientific Method

2. Scientific Method Steps
Observation
Hypothesizing
Prediction
Experiment
Collecting Data
Drawing conclusions

3. What is the scientific method?
It's a simple process of trial and error used to answer questions about the world.
Two Principles:
Events in the natural world have natural causes.
Uniformity: fundamental laws of nature operate the same at all places and at all times.

4. Observation Taking notice of things and asking why and how they occur.
Example Observation: Worms of the same species grow bigger in warmer areas of the country.
Question: What causes worms to grow bigger?

5. Hypothesizing Hypothesis:
An educated answer to the question from your observation.
A hypothesis must be testable and falsifiable.
Hypothesis: Heat causes worms to get bigger.

6. Prediction
A prediction is what is expected to happen if the hypothesis is true.
Prediction: If earthworms are exposed to high temperature, then they will grow bigger than those exposed to low temperature.
Must write “If…., then…”

7. Experiment Testing a hypothesis. A Controlled Experiment compares :
a control group:
used only for comparison and left alone
a experimental group (s):
Those that will be tested and manipulated
Both groups must be identical, except for what is being tested.

8. Worms must be from the same species.
The Worm Experiment
My hypothesis is that heat causes earthworms to grow bigger
Control Group Experimental Group
Worms must be from the same species.

9. Independent var. affects the Dependent var.
The Worm Experiment
Control group:
Group C: Earthworms at regular room temperature 32 degree C.
Experimental Group:
Group A: Earthworms exposed to high temp. >32 degree C
Group B: Earthworms exposed to low temp. <32 degree C
Independent Variable: Factor that is different between the control and the experimental group.
I.V.=Temperature.
It’s the only thing that’s different btw the groups.
Dependent Variable: what’s being tested.
D.V. = Growth
The growth of the worms is dependent on the temperature (independent variable).
Independent var. affects the Dependent var.

10. The Worm Experiment Control Group Experimental Group Group A Group C
High Temp.
(>32 degrees C)
Group C
Normal Temp.
(32 degrees C)
Group B
Low Temp.
(<32 degrees C)

11. Collecting Data Qualitative Data Quantitative Data
Data: information observed and gathered during an experiment.
Qualitative Data
Descriptions (warm, yellow, short, fast, drawings etc.)
Quantitative Data
Recorded Measurements (35 °C, 570 nm, 20 cm, 1m/s)

12. Is my hypothesis supported or falsified?
Drawing Conclusions
The data collected from the experiment is analyzed and used to either support or falsify the hypothesis.
RESULTS:
Earthworms in the high temp. grew twice as fast as those in the control group.
Low temp. worms grew half as fast as the control.
Is my hypothesis supported or falsified?
Days 1 2 3 4 5
Group A
>32 °C Mass
.93
.97
1.1
1.5
1.9
2.3
Group B
< 32 °C Mass
.96
.98
.99
1.0
Group C
At 32 °C Mass
1.3
1.7
2.1

14. Hypothesis vs. Theory
A hypothesis is tested (over and over again) until it is credible enough to be labeled a “theory”
Theory: an elevated status in science indicating the best known explanation for some phenomenon.
A theory that is confirmed may be further elevated to the status of fact or scientific "law".

15. Questions:
What’s the problem with using different kinds of worms instead of the same kind in a controlled experiment?
Explain how the independent variable affects the dependent variable.
Compare and contrast hypothesis from prediction.