1. Scientific Evaluation
Being Objective

2. Measurements
Taking accurate measurements is only one aspect of scientific experiments
When recording measurements, be sure to list the units
Important to indicate whether you measured in metric or English units

3. The Metric System
How the world communicates the results of its experiments
Decimal system of measurement
All units divisible by 10

4. Base Units Most common base units used in the metric system
Gram (g)
Meter (m)
Liter (L)
Second (s)
Celsius degree (°C)
All other units in metric system derived from these base units

5. Prefixes Kilo (x1000) [k] Hecto (x100) [h] Deka (x10) [D]
BASE UNITS (x1)
Deci (x0.1) [d]
Centi (x0.01) [c]
Milli (x0.001) [m]
Now make a mnemonic device for the metric prefixes using the letters in red

6. Putting it all together…
Kilosecond  (ks = 1000 seconds)
Hectometer 
Centigram 
Dekasecond 
Deciliter 
Kilometer 
Milligram 
(hm = 100 meters)
(cg = .01 gram)
(Ds = 10 seconds)
(dL = .1 liter)
(km = 1000 meters)
(mg = .001 gram)

7. “m” How can we tell whether an “m” stands for a meter or milli-?
M at the end = meter
M at the beginning = milli
M by itself = meter

8. Practice k h D (base) d c m 400 millimeters in meters
k h D (b) d c m
4 0 0
=0.4 meters
5.27 kilograms in grams
5.2 7
=5,270 grams

9. Practice k h D (base) d c m
Using your BYOT or iPads go to
Type your first & last name (no spaces) for the “nickname”
Your message should include answers to the following:
6.82 Dekaliters in deciliters
175 millimeters in hectometers
4 kilograms in centigrams

10. The Big Five Gram (g)- measurement of mass
Mass: a measure of the quantity of matter
Often confused with weight: the measure of force of gravity between two objects
Equipment to measure mass
Triple beam balance
Electronic balance
Calibrate: adjust a measuring instrument to a standard
Tare: mass of the container, which is subtracted from the total mass of the container and substance to find the mass of just the substance

11. Now it’s your turn…
Complete “Balancing Chewing Gum” Experiment

12. The Big Five Meter (m)- measurement of length
Length: the distance between two points
Equipment to measure length
ruler
What if the object you need to measure is a potato?

13. The Big Five Liter (L)- measurement of volume
Volume: the amount of space occupied by an object
Usually measure liquids by their volume
Be careful when measuring the meniscus: curve at the surface of a liquid

14. Equipment to Measure Volume
Beaker: deep, wide-mouthed container with a pouring lip
Erlenmeyer flask: flat-bottomed, cone-shaped container
Graduated cylinder: tall container used to accurately
measure the volume of liquids to the nearest milliliter
Buret: graduated glass tube with a control valve at the bottom

15. The Big Five Second (s)- measurement of time
Critical to have someone act as a timer during experiments
Record start and stop times using a clock/watch
Failure to accurately monitor time can make your entire experiment invalid

16. The Big Five
Celsius degree (°C): is most commonly used unit of temperature
Water freezes at 0°C
Water boils at 100°C
Temperature: a measure of heat intensity
The US still uses Fahrenheit scale for everyday temperature measurements

17. Lab Experiment: “Measuring the Volume of Irregularly Shaped Objects”
How do you measure the volume of a biscuit?
Once completed with the lab..
Work on “Metric Units” worksheet

18. Scientific Method An organized approach to solving problems
ASK QUESTIONS
DEFINE THE PROBLEM
CONDUCT RESEARCH
STATE THE HYPOTHESIS
DESIGN THE EXPERIMENT
CONDUCT THE EXPERIMENT
EVALUATE THE RESULTS
REPORT THE RESULTS

20. Steps in the Scientific Method
ASK QUESTIONS
Why are you interested?
What are the benefits of investigating this topic?
How can this be analyzed?
For example, the Best Bean Company’s navy bean crop was destroyed by plant disease this year.
Is there a substitute for navy beans that will be comparable in flavor, texture, color, and cost?

21. Steps in the Scientific Method
DEFINE THE PROBLEM
What is the exact purpose of your specific experiment?
In class, problem = purpose for experiment
Ex: To find a substitute bean similar in color, shape, texture, flavor, cooking characteristics, and cost, as well as its’ impact of customer approval

22. Steps in the Scientific Method
CONDUCT RESEARCH
List possible causes of your problem
Books, articles, online sources
Referred to as “Review of Literature”
Check information on related studies
Ex: finding names and descriptions of different kinds of beans or looks for recipes using other types of beans

23. Steps in the Scientific Method
STATE THE HYPOTHESIS
Hypothesis:
A possible solution to the problem
an educated guess or prediction
An “if, then” statement
Ex: Greater northern beans, pink beans, and pinto beans are acceptable substitutes of navy beans.

24. Steps in the Scientific Method
DESIGN THE EXPERIMENT
Variables:
Factor that is being changed
Ex: kind of bean
Control:
Standard against which you measure all changes
Ex: navy bean
Variation:
Change you made in the experiment
3 variations (greater northern, pink, and pinto beans)

25. TYPES OF VARIABLES Independent Variable Dependent Variable
The variable that is changed by the scientists
The “I control” variable
Dependent Variable
The variable that might change because of what the scientist changes
What is being measured

26. Remember! Your hypothesis can TELL you what your variables are!
Example: If I drink Mountain Dew before bed, then I will not sleep very much.
IV: Drinking Mountain Dew
DV: the amount of sleep

27. Use this hypothesis to identify the variables:
Practice
Use this hypothesis to identify the variables:
If I consume a large amount of sodium, then my body will dehydrate more quickly.
IV:___________________________________________
DV:__________________________________________

28. Use this hypothesis to identify the variables:
Practice
Use this hypothesis to identify the variables:
If I brush my teeth more, then there will be less plaque build-up on my teeth.
IV:___________________________________________
DV:__________________________________________

29. Now read the experiment and identify the variables:
Practice
Now read the experiment and identify the variables:
Elizabeth wanted to test if temperature affected how fast milk goes bad and curdles. She left milk in a room temperature closet, a fridge, and an oven that was turned on low heat. She then measured how rotten the milk was after 10 days.
IV:___________________________________________
DV:__________________________________________

30. Going back to your hypothesis..
Hypothesis: an educated guess or prediction; an “if, then” statement
If _____independent variable _____
then _____dependent variable_____

31. Example:
Independent Variable: I feed my cat a lot of food Dependent Variable: her weight will increase If ______________________________ then ______________________________

32. Remember!
Try to use INCREASE and DECREASE in your hypothesis! Example: IF I increase the amount of water I drink, THEN I will increase the efficiency of my kidneys.

33. Steps in the Scientific Method
CONDUCT THE EXPERIMENT
In class, groups will often conduct different variations
SO…..
Follow experiment directions EXACTLY in order to ensure accurate data

34. Steps in the Scientific Method
DATA COLLECTION
Numerical Observations:
i.e. Quantitative Observations
Still require units and descriptions or the numbers won’t make sense (time, temperature, mass, etc)
Descriptive Observations:
i.e. Qualitative Observations
Factors such as color, texture, temperature, and odor

35. Steps in the Scientific Method
EVALUATE THE RESULTS
Read data, observations, and notes
Look for patterns, common factors, changes, and questions
Look for answers to the questions and support for/against your hypothesis

36. Steps in the Scientific Method
REPORT THE RESULTS
Form a CONCLUSION that analyzes and applies data
Answers how, what, where, when, or why
Many experiments may lead you to more than one conclusions OR more than one option to solve your problem
State ideas for further research
Lab reports

37. Now try it on your own!
Complete worksheet “A Variable Way to Practice Variables”

38. Assignment: The Twinkie Project
Using the steps of the scientific method, create a hypothesis about Twinkies