1. Catalyst
Students conducted an investigation to determine if unknown liquids were acids or bases.
1. What is the scientist changing in this experiment?
2. What is the independent variable in this investigation?
3. What is the dependent variable in this investigation?

2. Announcements
Tonight for Homework: Conclusions and Human Error worksheet

3. Today’s Objectives SWBAT define scientific conclusion.
SWBAT write a precise and specific scientific conclusion based on data.
SWBAT explain why bias is a concern for scientists
SWBAT identify sources of bias
SWBAT identify errors in scientific investigations
SPI0807.Inq.5: Identify a faulty interpretation of data that is due to bias or experimental error.

4. Which is better Coke or Kroger soda?

5. Draw A Data Table in Your Notes
Type of Soda
Number People Preferring
What is the independent variable?
Type of soda
What is the dependent variable?
Number of People Preferring
How should you label your table?
You will get a Dixie cup of each sample
Do NOT drink the sample until Ms. P tells you

6. Title Your Notes
Inq. 5: Human Error

7. Scientific Conclusions
A scientific conclusion must be supported by research or data!!
A conclusion accepts or rejects your hypothesis. Scientific conclusions do not always have to support your hypothesis.
Conclusions are valid if a scientist has made no errors

8. Errors in Science
Two types of errors in science: human error and experimental error
Today, we will be taking about human error!

9. Human Error A human error is an error made by the scientist
The most likely error in an experiment is human error. Unfortunately, we are not perfect 
A human error makes the conclusion not valid.
Types of human errors:
Biases
Not following the procedures of an experiment (for example, missing or adding a step)
Making an error in measurement or calculation
Assuming a cause and effect relationship without data
Not having a controlled experiment

10. Biases
Biases are wishes or expectations that will lead to a certain conclusion
Can be intentional or unintentional
Some sources of biases:
Trying to persuade someone else
Relying on incomplete information
Past experiences are influencing you

11. Biases in Action
Ms. P thinks that Penn State is the best university in the nation! She conducts an experiment to see which college campus is the cleanest campus and she concludes that Penn State does.

12. Biases: Need to make careful observations
Example: Testing a drug, must measure the symptoms, not whether the patients say they feel better

13. Procedure You must follow the procedures of an experiment exactly.
If you make an error in the procedure, you must completely re-do the experiment!

14. Making an Error in Measurement or Calculation
Most frequent error  calculating change
When calculating a change in an experiment, you must always do the final value minus the initial value
Change =final - initial

15. Examples of Not Calculating a Change Correctly
After placing the rock in the graduated cylinder, Ms. Baggs said the volume of the rock was 30 ml.
Remember – the volume of the rock is equal to the change in volume (final volume – starting volume)
This is an example of human error because he made the mistake – if she was perfect, she would not have made this mistake!

16. Another Example
A farmer is trying to see what type of fertilizer has the largest change in height growth on his wheat.
He measures the height of the wheat after each fertilizer has been administered.
Remember, change = final – starting.
What does the farmer know?
Final - ?????
How is he suppose to know how much it grew? He only know its final height. What if one started out much taller?

17. Want kind of error is this?
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?

18. Human error Measuring from 100 end 95.4 is the wrong number
Answers:
Measuring from 100 end
95.4 is the wrong number
‘mm’ is wrong unit (cm)
Hand-held object, wobbling
Gap between object & the rule
End of object not at the end of the rule

19. Cause and Effect
In order to assume a cause and effect relationship has occurred, there has to actually be proof of a cause and effect!!!
You need to back, back, back that up with evidence. You must have experimental data that proves there is a cause an effect relationship between your independent and dependent variable, before assuming there is one.

20. Annie could hear the music playing over the loud speaker in the mall
Annie could hear the music playing over the loud speaker in the mall. She and her mother were shopping for a present for her father. Annie could see a big line in the center of the mall. She wondered what all the people were waiting for. She then heard a jolly "HO! HO! HO!" from the center of the crowd and she quickly realized what the people were waiting on. As Annie and her mother walked through the mall, she noticed that the store windows were decorated with green, white, and red decorations.

21. It actually was not Santa…
It was the Allstate guy!!!!

22. Controlled Experiments
You also need to make sure your experiment is controlled.
A controlled experiment has:
ONE independent variable and ONE dependent variable
Control group and experimental group
All other variables are controlled (control variables)

23. Stop and Jot
You will have two minutes to work with the person next to you to answer the question on the next slide
Answer the questions in your notebooks
Work quietly and efficiently

24. An Example
An experiment is conducted to test the effect of UV lights on the number of deformities a frog has. The following data is recorded.
What is the independent variable?
What is the dependent variable?
What are some control variables?
What is the control group?
Group
Kind of Frog
Number of eggs
Temperature
UV light exposure
# of deformities 1
Leopard frog
100
25° C
0 days 2
15 days 3
24 days 15

25. An Example
What is the independent variable? What is being changed? What is the cause? Amount of UV light exposure
What is the dependent variable? What is being measured? The number of deformities the frog has
What are some control variables? What must stay the same so that it does not affect on data? The kind of frog, the number of eggs, the temperature.
What is the control group? What is the group that does not receive the experimental treatment and must be used for comparison? Group 1 because it receives no UV light exposure. This is how we know that it is the UV light that is actually doing the affecting.

26. Control Variables
For example, if Mary wanted to see the effect of saltwater on plant growth, she needs to use the same type of plant, give it the same amount of sunlight, the same amount of water, etc. She also needs to compare it to a plant with regular water in order to make a conclusion.
Example: Juan wanted to see how the amount of food given to a dog affects its energy level. He has two dogs at home: a small poodle and a big Lab. Can he use these two dogs and only these two dogs in his experiment? Why or why not?

27. Think, Pair, Share!
1. I will show an experiment and ask you a question about it.
2. You will have 10 seconds to think about the answer by yourself. This step should be completed silently.
3. Then you and your partner will come share your ideas and write your answer in your notebook.

28. Example #1
Two birds are fed different types of bird seed to determine which type causes the bird to gain more weight. Which of the following would be an experimental error?
A. The birds are different species.
B. The birds are allowed to eat all the seed they wanted.
C. The birds are exposed to different amounts of light and heat.
D. All of the above.

29. Example #1
Two birds are fed different types of bird seed to determine which type causes the bird to gain more weight. Which of the following would be an experimental error?
We can only have ONE independent variable, which means we can only change one thing! The ONLY thing we should be changing is the type of seed!
A. The birds are different species. they have to be the same species
B. The birds are allowed to eat all the seed they wanted.  they need to eat the same amount of seed!!
C. The birds are exposed to different amounts of light and heat.  the need to be exposed to the same amount of light!
D. All of the above.

30. Example #2
Jonquil decides to test the effect of light exposure on the growth rate of a particular species of plant. He sets up his experiment as shown above and measures the height of the plants each day for a month. He makes sure to water the plants daily, each with the same amount of water. After collecting and analyzing the data, he notices that there is little variation in the height of the plants. Even though the plants received different amounts of light from each lamp, they are all the same height. Jonquil is surprised by these results. What should he have done differently?
A. Measured the plants more often
B. Used the same amount of light
C. Moved the plants away from the window

31. Example #3
Ms. Burke was raving about how well she could bake. Ms. P got tired of listening to her and decided to have a bake off to settle Ms. Burke once and for all. Both teachers bakes they’re best desserts and handed them out in class. As Ms. Burke handed hers out she talked about how delicious they were to each student. What kind of error is taking place?

32. Independent Practice
Complete the independent practice silently and independently
When you have finished, tape your work into your note book
Get your homework when you have finished
This is due TOMORROW