1. The Practice of Science
Designing an Investigation

2. There’s no such thing as THE scientific method!
The Process of Science
There’s no such thing as THE scientific method!
It’s more like “methods that are scientific” or “a scientific process”
The process of searching for explanations about the natural world doesn’t always follow a set of step-by-step procedures/rules.

3. NOT ALL scientific knowledge comes from experiments.
The Process of Science
NOT ALL scientific knowledge comes from experiments.
Controlled experiments are only one type of scientific investigation
That said, your science fair project should be a controlled experiment (unless you are working with Mr. Rodriguez on a different type of investigation).

4. SCIENCE FAIR: Choosing a Topic
Choose a topic to investigate.
Make sure it is interesting to you.
Make sure you have the resources (tools, ability, time) to investigate it.
Make sure there is an adequate research base available to you.
Make sure there are answerable questions that are relevant to your topic.
Our class project topic will be…

5. Soda & Mentos Reaction

6. Diet Coke & Mentos Fountain

7. SCIENCE FAIR: Research Question
Refine your topic into a testable question.
A testable question is one that can be answered with data you gather.
Identify variables that may have an impact on the original set of conditions. Choose one of these variables to test.
Effective research questions often identify both the independent (test) variable and the dependent (outcome) variable, ex: How does “x” affect “y”?

8. SCIENCE FAIR: Variables
The identification and control of variables is what characterizes a controlled experiment.
Independent Variable
Only ONE
Factor being tested/manipulated to see its impact
Dependent Variable
Factor being observed/measured to see how it is affected
Constants (Controlled Variables)
All other factors must be kept the same so they don’t influence the outcome

9. Soda and Mentos: Research Question
Brainstorm some testable questions for our soda and Mentos investigation.
Think of variables that may have an effect on the reaction:
INDEPENDENT?
Brand/Type of Soda/Mentos
Number of Mentos
Temperature of Soda/Mentos
DEPENDENT?
Height of Spray
Duration (Time) of Spray
Amount of “Fizz”

10. SCIENCE FAIR: Researching Your Topic
Search for information relevant to your topic to generate possible answers.
Try to consider every reasonable alternative
Use your research to narrow down possible explanations
Hypothesis vs. Prediction
A hypothesis is a testable explanation of the phenomenon.
A prediction is a statement of the expected outcome.
Ex) If (your hypothesis) is true, then (your prediction) will be observed.

11. Soda and Mentos: Research
Have others already attempted to answer this question?
What information might be helpful to answer this question?
What causes the reaction?
What ingredients are present?
How will the environment affect the reaction?
Where can we get this information?
Mythbusters episode
Internet research

12. SCIENCE FAIR: Planning Your Investigation
Plan out a timetable for your investigation. Make yourself deadlines and stick to them!
Design your investigation.
What type of investigation? How can you test your hypothesis?
What data will you need?
How/What will you measure/observe?
How will the data help you answer the question?
How will you control variables (if necessary)?
What materials will you need?

13. SCIENCE FAIR: Planning Your Investigation
Data vs. Evidence
Data consists of information you gather during your investigation
Observations and/or measurements
Evidence is data that has been analyzed and interpreted in support of a claim
Not all data will be evidence…
Scientific Confirmation
Ensures consistent and predictable results through repetition and replication
REPETITION – multiple trials
How do you know when you have enough trials?
Your data is consistent and predictable
REPLICATION – another scientist is able to duplicate your investigation with similar results

14. Soda and Mentos: Investigation Planning
What type of investigation?
What data will we need?
How/What will we measure/observe?
How will the data help us answer the question?
How will we control variables?
What materials will we need?

15. SCIENCE FAIR: Analysis
How can we learn from the investigation?
What can we learn from the investigation?
Think of ways to report your evidence.
What data is important? How can you highlight that importance? What can you COMPARE?
What relationships exist? How can you show them?

16. SCIENCE FAIR: Conclusions
What conclusions can be drawn?
Scientific CLAIMS must be supported by EVIDENCE. EVIDENCE must be JUSTIFIED with accepted scientific principles.
Note the word “supported” above…how is this different from the word “proven”?
Scientific explanations are TENTATIVE (open to change).
There is NO SUCH THING as “proof” in science. Scientific theories cannot be proven (despite what you may hear from actual scientists or the media).
We say “The results support…” or “The data suggests…” rather than “…has been proven”.

17. Soda and Mentos: Analysis
What data is important?
How can we highlight its importance?
What relationships exist?
What can we compare?
Does the data show relationships between the variables?
How can we show them?

18. Soda and Mentos: Conclusions
What conclusions can be supported by our data?
What data do we have to draw from?
How does that data support our conclusion?
Why are we able to use that data to support our conclusion? How can we use scientific concepts to explain the relationships?