Physical Science 8th Grade

Physical Science

The study of matter and energy

Theory

A time tested explanation
for events that occur in the natural world

Law

a scientific theory that has
been tested many times and is
generally accepted as true

Scientific Method

Follow these guidelines

Title

A problem stated in the form of the problem.

Research

Gather information using books, the
internet, other experiments etc.

Hypothesis

Use the research to make an
educated guess about the answer to
the problem
Use an if, then and because
statement.

Experiment

Create an Experimental Design Diagram
(EDD)
Perform the experiment
Record data and make observations
Qualitative: use of five senses; It looks like, it
smells like?
Quantitative: use actual numbers and
measurements, these observations are more
reliable.

Analysis

The data should be analyzed to look
for any patterns or relationships
Data should be represented using a
graph

Conclusion

Is the hypothesis correct?
Why? Or Why not?
Use data from the experiment to
support
How can the experiment be
improved?

Matter

Matter is what EVERYTHING is made
of (air, solids, liquids & gases)
All matter has the physical properties
of mass, inertia, weight, volume, and
density
Matter can have Physical and
Chemical properties

Mass

the amount of matter in an object
the amount of inertia an object has
units of measure: g, kg
Doesn?t change due to environment
for example: your mass would be the same on the
moon

Inertia

an objects tendency to resist any change in
motion
all objects want to keep doing what they are
doing, whether still or moving

More Mass = More Inertia

Nothing Here

Weight

The measure of gravitational pull
between objects
can change due to environment
For example, your weight would be less on
the moon.
(units of measure: Newtons (N), pounds
(lb)

Volume

Volume-
The amount of space an object takes up
units of measure: cc, cm3, mL, L
To determine the volume of:
Liquid: use a graduated cylinder (unit: mL)
Regular Shaped Object: (L x W x H)
(unit: cc, cm3)

To Determine Volume...

Irregular Shaped Object:
Use water displacement:
Measure the starting volume in a
graduated cylinder, add object, read
ending volume. The difference is the
volume of the object. (units: cc, cm3)

Density

The amount of matter/stuff packed into a
given amount of space
the amount of mass in a certain volume
units: g/cm3 & g/mL

Formula:
Density
=
Mass
Volume

The density of a substance does not
change regardless of the amount/size of
the object
Example= the density of water is 1 g/mL

Physical Properties

are characteristics that can be
observed without changing the
identity of the substance
Examples: mass, weight, volume,
density, boiling point, smell,
viscosity, color, shape, texture,
hardness

Title Continued

Format:
What is the Effect of the Independent
Variable on the Dependent Variable?
Example:
What is the Effect of Different Brands of
Fertilizer on the Growth Height of Bean
Plants?

Hypothesis Continued

**an educated guess about the answer
to the problem**
Format:
If (choose a level of IV) then (make a
prediction of DV) because (use
research or background

Hypothesis Example

If fast grow is tested, then the bean plant
growth height will be highest because fast
grow advertises a special ingredient for
extra high growth.

Independent Variable

The factor/variable that is purposely
changed by the experimenter, what
the experimenter decides to
change/test
?what ?I? change (or test)
Usually three or four levels

Levels of IV

the changes that are made to the
independent variable
For example:
Three levels of fertilizer would be
miracle grow, easy grow and fast
grow!

Trials

the number of times the experiment
is repeated for each level of the IV
Repeated trials are done to reduce
the effect of errors

Dependent Variable

The factor that is measured,
counted or observed!
the factor/variable that responds to
the changes in the IV

Factors Held Constant

all factors which remain the same for
each repeated trial and level of IV
(formerly called constants)

Control

An experiment without a
variable; used as a comparison (there
will not always be a control)