NATURE OF SCIENCE
Mrs. Cassel
Rm 106
SCIENCE
HOW DO WE “DO” SCIENCE?

Scientific Method (Inquiry)

People
What is Problem or Researchable Question

In
Gather Information

Hershey Create a Hypothesis
(if. . . Then. . . Because. . . Statement)

Eat
Experiment

Dark
Collect and Analyze Data

Chocolate Form Conclusion
QUALITATIVE VS. QUANTITATIVE

Qualitative
Observations or Data that are based on your 5 senses
and are DESCRIPTIVE.
 Ex: The mineral is yellow in color and smells like
rotten eggs.


Quantitative
Observations or Data that are measureable and
NUMERICAL.
 Ex: The mineral has a mass of 26g and a volume of
13 cm3. Its Density is 2g/cm3.

INDEPENDENT

VS.
DEPENDENT VARIABLE
Manipulated variable Independent variable

The thing you choose to change.
The IF part of the hypothesis

Responding variable  Dependent variable

The factor that may change because of the
Independent variable.


What you are observing or measuring
The THEN part of the hypothesis
If I increase the temperature of the water, then
the amount of sugar dissolved increases.
THEORY VS. LAW

Theory

An attempt to EXPLAIN something observable in
nature. Supported by much repeated testing.


Big Bang Theory: attempts to explain how the Universe
was formed and why we see evidence that the Universe is
expanding.
Law

Attempts to DESCRIBE something observable in
nature. Does not try to explain it, only states that it
happens.

Law of Gravity: States that all things in the Universe are
attracted to all things in the Universe with the same force
and are dependent on their Mass and Distance between
objects.
RESEARCHABLE QUESTIONS






Causal: Cause and Effect Questions Designed
to determine whether one or more variables causes
or affects one or more outcome variables.
Ex: What is affect of Red Bull on heart rate?
What is the effect hand fatigue on reaction time?
How does exercise affect the rate of carbon dioxide
production?
How is the diffusion of air freshener influenced by
temperature?
How does
affect
of the gum?
HYPOTHESIS
What is affect of Red Bull on heart rate?
 If we drink 100 ml of Redbull, then our heart rate
will increase.
 How does exercise affect the rate of carbon
dioxide production?
 If we increase our exercise by double, then the
rate of carbon dioxide production will increase.
 How is the diffusion of air freshener influenced
by temperature?
 If we increase the temperature of the air
freshener by 10 degrees, the air freshener
diffusion will increase.

HYPOTHESIS

If we
to the gum,
then
will increase.
Quantify the Independent variable.
 Use terms increase/decrease to show direction of change.

DATA TABLE

When creating a data table you must decide the
number of columns and row.

1st column on the left is the Independent Variable

Don’t forget to include a UNIT in the Label
Time
Gum
Chewed
(min)
2
4
6
Length
of
Stretch
(cm)
Trial1
Length
of
stretch
(cm)
Trial 2
Length
of
Stretch
(cm)
Trial 3
GRAPH
The independent variable is plotted on the x-axis
 The dependent variable is plotted on the y-axis

DATA ANALYSIS

Trend Line: A line on a graph showing the
general direction that a group of points seem to
be heading.
RELATIONSHIP OF VARIABLES

Direct Relationship (Positive)

This means as the Independent variable INCREASES
the Dependent variable INCREASES.
RELATIONSHIP OF VARIABLES

Inverse Relationship (Negative)

This means as the Independent variable INCREASES
the Dependent variable DECREASES.
DATA ANALYSIS

Strength of Relationship: How closely the
points follow the trend line, shows the strength of
the relationship.
DATA ANALYSIS

In a lab report, the data analysis is where you
tell us specific things about the data on your
graph.
What is the relationship between the two variables
you are observing? (Positive, Negative)
What is the strength of that relationship? (Strong,
Weak)
Give data to support those two things.
1.
2.
3.
1.
Ex: After 1 minute the gum only stretched 20 cm whereas
at 3 minutes the gum stretched 100 cm.
CONCLUSION
State your conclusion whether you accept, reject, or
need to modify your hypothesis.
 State how you could improve your experiment to
make it more valid and reliable.

1.
2.
3.
Acknowledge hidden variables that you couldn’t control
or chose not to because of situation. (validity)
Increase the number of trials, improve equipment, etc.
(reliability)
Further Study: Now that you’ve completed this lab,
what study might you do based on this one?