1. The Scientific Method

2. THE SCIENTIFIC METHOD http://glencoe. mcgraw-hill
Question
Observation
Hypothesis
Experiment
Data
Conclusion

3. VARIABLES
The different factors that can change in an experiment An experiment usually has three types of variables: independent, dependent and constant

4. INDEPENDENT VARIABLES (What I CHANGE in an experiment)
This is the variable that you intentionally change throughout the experiment
A good experiment has only ONE independent variable
What are you physically doing to the experiment that might cause a change

5. DEPENDENT VARIABLES (What I OBSERVE)
The variable that responds and changes because of the independent variable (because of what you did)
Often measured at the end of the experiment

6. CONSTANT VARIABLES (What I Keep the SAME)
These could change and affect your experiment, but you do not want them to
This does not ever change in an experiment
Ex. Do plants grow better in darkness? Constant variable would be the amount of water you give the plants

7. EXAMPLES OF VARIABLES QUESTION INDEPENDENT VARIABLE (WHAT I CHANGE)
(WHAT RESPONDS)
CONSTANT VARIABLE
(WHAT I KEEP THE SAME)
Does heating a cup of water allow it to dissolve more sugar?
Temperature of the water measured in degrees Celsius
Amount of sugar that dissolves completely measured in grams
Amount of stirring
Type of sugar
Does fertilizer make a plant grow bigger?
Amount of fertilizer measured in grams
Growth of plant measured in centimeters
Same size pot for each plant
Same type of plant in each pot
Same type and amount of soil in each pot
Same amount of water and light
Make measurements of growth for each plant at the same time
Do bicycle fenders keep the rider dry when riding through a puddle?
The bicycle either has fenders or does not
The rider either gets wet or does not
Same type of bicycle
Same type of tires on bike
Riding at the same speed
Same size and depth of puddle
Who listens to music the most: teenagers or their parents?
The groups receiving the survey: teenagers or parents
The amount of time that each person listens to music per day measured in hours
Ask the question in exactly the same way to each individual

8. CONTROL A standard to which your results can be compared
These are exposed to the same conditions as the experiment groups, but there is no variable being tested
Examples: Growing plants in sunlight in a darkness experiment, no antibiotic on a bacteria study about testing new drugs (placebo group)

9. QUESTION
CONTROL
Does heating a cup of water allow it to dissolve more sugar?
ROOM TEMPERATURE
Does fertilizer make a plant grow bigger?
NO FERTILIZER
Do bicycle fenders keep the rider dry when riding through a puddle?
NO FENDERS
Who listens to music the most: teenagers or their parents
COMPARISON STUDY—NO CONTROL

10. Procedures
A list of materials needed to complete the experiment is given.
Step by step directions for how the procedure is performed is given.
Specific information for data collection are included.

11. IMPORTANCE OF REPEATING EXPERIMENTS
For results to be considered valid, experiments need to be repeated countless times to be sure that the same results occur

12. Types of Data
Qualitative: descriptions that do not include measurement. Examples would be color, texture, and appearance.
Quantitative: a number and unit is given for an exact measurement. Examples would be 12 feet, 3 grams, and 4.2 liters.

13. Data Analysis For quantitative data, averages are often calculated.
Totals are given for qualitative data. For example, 4 dogs were black and 2 were brown
A graph is made of the averages so that it is easier to interpret.
A sentence or two is given to summarize the numerical data.

14. Conclusion A summary of the experimental findings.
Restates the hypothesis.
Identifies whether the hypothesis was supported or rejected by the experiment.
Provides a possible reason for the results.
Discusses how the findings are useful.
Proposes ways to improve the experiment and/or additional questions to be tested.

15. SCIENTIFIC THEORY
An explanation or model for a scientific question that backs a hypothesis and is supported by results from many, many experiments
The theory of evolution
explains how organisms
change over time in
response to their
changing environment

16. SCIENTIFIC LAW
A rule that describes the behavior of something in nature
A scientific law typically describes what will happen, but not why
They are universally accepted as true
Examples include Newton’s Laws of Motion, law of gravity