1. Lab Procedures & The Scientific Method

2. How would you define the following?
Variable
Constant
Independent
Dependent
Control

3. Lab Reports
Lab Reports will be done in groups or on your own depending on the lab
All reports will have the same format, unless I give you something different
Rubric for reports

4. Anatomy of a Lab Report Title (1pt) – anything appropriate
You want to see which type of paper towel absorbs the most water, what could be a title for your lab?
Introduction (3pts) – usually just one paragraph, tell me why we are doing the lab
From the example above: In this lab we will look at which brand of paper towel absorbs the most water. We will use Brawny, Viva, and Bounty, adding water a cup at a time until no more water is absorbed.

5. Anatomy of a Lab Report
Hypothesis (2pts) – what do you think will happen
Using the paper towel example, come up with a hypothesis
If we were looking at what is the effect of temperature on plant growth, what could your hypothesis be?
Safety notes(1pt) – will be given but MUST be in your lab report

6. Anatomy of a Lab Report
Materials (1pt) – often listed on the lab so look!
Procedure (3pts)
Identify independent/dependent variable (1)
Pre-lab questions (1)
Steps to follow (usually given) (1)
Data (5 pts) – record your information you gather during the lab…no calculations!

7. Anatomy of a Lab Report Calculations (5 pts)
Any calculations you do (duh!)
Graphs
Must have headings, labels, units, key (if needed) and a title!
Error Analysis (2pts) – what could have gone wrong?
There is always error, so don’t leave it out
Usually found in the procedure or calculations portion

8. Anatomy of a Lab Report Conclusion (2pts) What did you learn?
Was your hypothesis correct? Why or why not?
Each lab report is worth at least 25 points. If there are questions to answer at the end, include them in the conclusion, but they may add points to the report.

9. Independent/Dependent Variables
What does independent mean?
The independent variable is the variable that WE change or that doesn’t change
In the paper towel experiment, we are changing the brand of paper towels, so that is the independent variable

10. Independent/Dependent Variables
What does dependent mean?
The dependent variable DEPENDS on the independent variable
The dependent variable is what we are looking at, what we study to see if it changes
In the paper towel example, the dependent variable is how much water is absorbed

11. Control Group
The control group is a group that does not have anything changing
A control is what you compare your experiment results to
Why would you use a control group?

12. Example 1
Dr. Imanut wants to examine whether a new drug increases the maze running performance of older rats. Just like aging humans, older rats show signs of poorer memory for new things. Dr. Imanut teaches two groups of older rats to find a piece of tasty rat chow in the maze. One group of rats is given the new drug while they are learning the maze. The second group is not given the drug. One week after having learned the maze, he retests the rats and records how long it takes them to find the rat chow.
What is the independent variable?
Age of the rats, type of maze, length of time it took the rats to run the maze, presence or absence of the drug
What is the dependent variable?
Age of rats, type of maze, length of time it took the rats to run the maze, presence or absence of drug

13. Example 2
A researcher wanted to study the effects of sleep deprivation on physical coordination. The researcher selected 25 year-old male college students and deprived some of the subjects of either 24, 36, or 45 hours of sleep.
In the study, what was the independent variable?
In the study, what was the dependent variable?

14. Example 3
A researcher wanted to know whether the number of people present would influence subjects’ judgments on a simple perceptual task. In each case the other members of the group gave an incorrect answer. The researcher then noted whether the subject conformed to the group decision.
What was the independent variable?
What was the dependent variable?

15. On your own… Simpson’s Homework Due Tomorrow
You may ask questions, but DO YOUR OWN WORK

16. Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.
Identify:
1. Control Group
2. Independent Variable
3. Dependent Variable
4. What should Smithers' conclusion be? 
5. How could this experiment be improved?

17. Homer notices that his shower is covered in a strange green slime
Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of "treatment" there is no change in the appearance of the green slime on either side of the shower.
6. What was the iniitial observation?
Identify the- 7. Control Group
8. Independent Variable
9. Dependent Variable
10. What should Homer's conclusion be?

18. Organizing Data Title of Known (Independent Variable)
Put your data into a table BEFORE graphing
Table should be set up as follows:
Title of Known (Independent Variable)
Title of Unknown (Dependent Variable)

19. Example
Every hour, over a 4 hour period, you checked the temperature of your experiment. Here is the information you collected: 1st hour, 32 degrees C; 2nd hour, 35 degrees C; 3rd hour, 33 degrees C; 4th hour, 34 degrees C
How would you arrange the data in the table?

20. Hour Temperature 1 32 2 35 3 33 4 34 Data Table (°C)
What am I missing?
Title for data table
Label for Temperature

21. Expectations for Graphing
Neat, legible writing – words and numbers
Use a Ruler!
Give your graph a Title
Label your X and Y axis
Are the numbers meters, days, months?
Y-axis is always the DEPENDENT variable
What you do not know..found out in experiment
Quantity or Amount

22. Expectations of a Graph
X-axis is always the INDEPENDENT variable
What you know
Time, Date, Days, People, etc
Key/Legend to explain colors, shading, etc.

23. Types of Graphs Line graph Bar graph Shows changes in information
If more than one line is necessary, use different colors for each line
Bar graph
Quick picture of organized data
Each bar shown must be the same width and spaced apart equally
Color or shade each bar differently, include key

24. Types of Graphs Circle Graph (Pie Chart)
Shows quick picture of data based on percentage of 100
Each section represents a smaller percentage
Color/shade each section differently
__% ?
50%
25%

25. Types of Graphs
Using the data table we created earlier, which type of graph would you use to present the information? Why?
Draw the graph

26. Types of Error We are human, so we make mistakes
Where can we look for mistakes?
First check measurements
Then check procedure
There are several types of errors: Random, Systematic, and Linked

27. Random Errors Errors that produce non-reproducible data
Doing something different each time you try the experiment
Ex: Don’t clean your instruments properly and some residue is left over
Always some randomness, but shouldn’t be significant

28. Systematic Errors Data often looks consistent and reproducible
Doing something your not aware of that causes all measurements to be off the same amount
Ex: Ruler starts at 2” instead of 1”, but you don’t realize it, something is stuck at the bottom of a beaker you are measuring out of

29. Design a Lab
Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which is a commercial hair product) affect the speed of hair growth". Her family is willing to volunteer for the experiment.
Describe how Lisa would perform this experiment. Identify the control group, and the independent and dependent variables in your description.

30. Putting it all together…
Now that you know about lab reports and how to put them together, we should do one!
Soap Bubbles Lab
Safety: Do NOT eat the soap or suck in on the straw, keep soap out of eyes