1. Bias and Error in Science.
Write notes in this color!!!

2. Definitions : evidence
‘evidence’ is data which is judged to be relevant.
For example:
When you investigate cooling:
the temperature data is relevant,
so it is evidence.
The length of the thermometer is not relevant,
so it is not evidence.

3. Definitions : evidence
‘evidence’ is data which is judged to be relevant.
The evidence needs be:
Reliable
and
Valid.

4. Reliability Reliable data is evidence you can trust.
If someone else did the same experiment,
they would get the same result.
Your evidence will be more reliable if you repeat your readings.

5. Bias Bias Bias is Very Bad! Notes Science
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Bias: this means you are prejudiced towards or against something and that you allow your views to affect the results of your experiment.
Science is about obtaining accurate results
so bias should NEVER be allowed to influence
your experimental results!
Bias is Very Bad!
Bias
Bias

6. Example: You are doing research to determine which NFL quarterback has the greatest accuracy with throwing a football, and your favorite football team is the Tennessee Titans.
You are disappointed to learn that the Titans' quarterback is the second most accurate instead of the first.
Yet because this is your favorite team, you change the data so that this quarterback appears to be the most accurate.
This is BIAS, and it should
NEVER be allowed in science.

7. Identify the bias or error in this situation
Example: Bubba loves extra salt on his “French-fried taters.”
He conducts an experiment to determine how much
better french-fries taste with lots of extra salt.
Identify the bias or error in this situation
ANSWER: Because Bubba likes extra salt on his fries, he
wrongly assumes that everyone else will like extra salt too.
He is biased toward salt, so his results will contain errors.
BIAS should NEVER be allowed in science experiments!

8. BIAS should NEVER be allowed in science experiments!
A Case of Bieber Fever
Two students who love Justin Bieber’s music do an experiment to
measure how long people have to hear one of Justin’s songs before
they too fall in love with his sound.
Question: Which choice below most likely will occur in this case?
A) Bias C) Song and Dance
B) End of the world D) World Peace
Answer: These two students are biased towards Justin Beiber, so their results will probably be biased and wrong too.
BIAS should NEVER be allowed in science experiments!

9. Solutions to Bias in Science
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Solutions to Bias in Science
Humans are imperfect, so bias happens both intentionally and unintentionally.
Ways to Reduce and/or Eliminate Bias
Be aware that bias can and does happen.
Strive to recognize it, and eliminate it from your experiments.
Follow the steps and principles of the scientific method.
Most importantly, make sure that others rigorously review your work looking for bias.

10. Notes Science Errors in Science
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Errors in Science
Avoid Mistakes:
One small error can result in all your experimental data being wrong.
So scientists work very hard to avoid making mistakes.
Peer Review:
One key way scientists deal with this issue is by having other scientists review their work to check for mistakes.
This very common practice is called peer review.

11. What is an error? An error is a mistake of some kind...
…causing an error in your results…
…so the result is not accurate.

12. Notes Science To Avoid Mistakes:
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To Avoid Mistakes:
Make sure you are following the steps of the scientific method.
Make sure you have only one independent variable at a time.
Make sure you correctly identify your dependent variables.
Make sure you include valid control experiments.
Make sure you record in detail every step of your experiment.
Ask someone else to review all your work (peer review).

13. Human error
Example 1
Professor Messer is trying to measure the length of a piece of wood:
Discuss what he is doing wrong.
How many mistakes can you find? ( Hint there are 6 mistakes)

14. Human error Measuring from 100 end 95.4 is the wrong number
Answers:
Measuring from 100 end
95.4 is the wrong number
Hand-held object, wobbling
Gap between object & the ruler
End of object not at the end of the rule
He is on wrong side of the rule to see scale.
How many did you find?

15. Random errors These may be due to human error, a faulty technique,
or faulty equipment.
To reduce the error,
take a lot of readings,
and then calculate the average (mean).

16. Reliability For example:
3 students measure the time for 1 swing of a pendulum:
Jo measures 1 swing.
Emma measures 1 swing, but 20 times, and calculates the average (mean) time.
Jack measures 20 swings and divides the time by 20.
Physics for You page 359
Discuss which method is the most reliable, and why.

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