1. Diet Coke and Mentos

2. Scientific Method
3 Minutes
Do Now: In the top left of your notebook… What is the difference between a dependent variable and an independent variable?
Objective:
In the top right of your notebook…
I can apply the scientific method when conducting laboratory exercises

3. Portfolio Review
Unit 1 – Scientific Method
9 objectives
27 pieces of evidence total
Folders!

4. Diet Coke and Mentos Lab
The purpose of this lab is to
Help you practice using the scientific method
Teach you expectations for lab reports in chemistry
Ensure that you understand all of the vocabulary that we use with the scientific method

5. Diet Coke and Mentos Lab http://video. google. com/videoplay

6. Think Pair Share What do you think might cause the reaction between Mentos and Diet Coke?

7. Mmm… Diet Coke and Mentos… the best combo 
Step 1: Problem (what is the question?)
Step 2: Research (do you already know something about this experiment)

8. Observations are what we see, smell, taste, hear, or feel.
Before we create a hypothesis, let’s make some observations and inferences…
Observations are what we see, smell, taste, hear, or feel.
Qualitative: Ex: red, blue, small, big, hot, cold, etc.
Quantitative: Involves a number
Inferences are a guess based on what you observe.
Inference:

9. What kind of data is this?
Class Poll
Ellen counts how many breakfast sandwiches are eaten in each 1st Period
What kind of data is this?
Qualitative?
Quantitative?

10. Step 3: Hypothesis – ÏF…..THEN….
What do you think is going to happen to the diet coke?
Step 4: Identify your variables
 What are we changing in the experiment?
 What are we observing in the experiment?
 What are we keeping the same?
Independent Variable (what we changed)
Dependent Variable (what we observed)
Control Variables (what we kept the same)   

11. Independent and Dependent Variables
Independent Variable: The variable that you CHANGE Dependent Variable: The variable that you observe and measure the RESULT of

12. Example-Rain and Zebras
Observation: A scientist studied the relationship between the amount of rain and the number of zebras born each spring. Independent Variable: ? Dependent Variable:

13. Control Variable
Also called a constant Control variable: a variable which does not change during an experiment so that results remain accurate

14. DO NOW OBJECTIVE Experimental Group
A botanist wants to determine what color ultraviolet light, if any, will result in the most optimal plant growth. He exposes plants to red, blue, and yellow ultraviolet light and compares their growth to the growth of plants exposed to the normal white light.
Experimental Group
I can apply the scientific method when conducting laboratory exercises
Write a hypothesis that relates to this experiment.
Identify the following variables:
Independent Variable
Dependent Variable
Control Group

15. Experimental Group & Control Group
Experimental group: the subject(s) being tested Control group: the subject(s) who do not receive experimental treatment and are used as a comparison

16. Don’t confuse control variable with control group.
CHALLENGE: Pitfall!
Don’t confuse control variable with control group.
Control variables, or constants, stay the same for the entire experiment
Control group is a group that is used for comparison

17. Example
Question: Is there a relationship between the number of hours spent studying and the score a student gets on the weekly quiz? Define the: Independent Variable Dependent Variable Control Variables Experimental Group Control Group

18. Example 2
Independent Variable Number of hours spent studying Dependent Variable Score on the weekly quiz Control Variables Amount of sleep Content knowledge Difficulty of the quizzes

19. Example 2
Experimental Group Students studying more (or less) hours than normal Control Group Students studying the normal amount of hours

20. Graphing Data
After collecting data, you need to make graphs in order to interpret the result
DRY MIX
Dependent Responsive Variable Y-Axis
Manipulate Independent Variable X-Axis

21. Diet Coke and Mentos Lab  Timeline
Thursday
Get into lab groups
Identify the ‘control’ group in the experiment
Control Group = what you compare the experiment to

22. Control Group  Diet Coke and Mentos
2-liter bottle of Diet Coke at room temperature
‘Mentos dispenser’ to get the Mentos into the Diet Coke  Make sure you ask Ms. B what this will look like!!!
3 mint Mentos

23. Determine what independent variable you want to manipulate in your experiment (5 minutes!!!!!)
Write out your group’s plan (Thursday/Friday)
Get your plan approved by Ms. Bergman (Friday)
Buy supplies (by Monday!!!)

24. What do you need to know?
Control
Independent variable
Dependent variable(s)
Materials needed
Lab report format

25. Lab Write Up Format Title Purpose Hypothesis Materials Procedure
Scientific Method
Lab Write Up Format
Title
Purpose
Hypothesis
Materials
Procedure
Data Collection
Analysis (answer questions)
Conclusion

27. Scientific Method Rewrite in your own words

28. Crossword puzzle (Due Friday) Work on Diet Coke and Mentos Lab
Homework
Crossword puzzle (Due Friday)
Work on Diet Coke and Mentos Lab
What is your procedure?
Do you need to get any supplies?