Unit B: Energy Flow in Technological...
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Transcript of Unit B: Energy Flow in Technological...
Unit B:
Energy Flow in
Technological Systems
The independent variable is also called the manipulated
variable. It is the one that the experimenter changes, or
has control over.
It is always plotted on the horizontal, or x-axis.
When looking at a data table, the independent
variable will be seen to increase by regular
intervals.
The dependent variable is also called the responding
variable. It is the one that the experimenter measures. It’s
value depends on the independent variable. It changes in
response to the change that the experimenter makes to the
manipulated variable.
It is always plotted on the vertical, or y-axis.
When looking at a data table, the
dependent variable will NOT be seen to
increase by regular intervals.
Volume (ml) Mass (g)
10.0 26.7
20.0 53.6
30.0 80.6
40.0 107.1
50.0 134.0
For example, to determine
the density of a liquid, a
student measures the mass
of various volumes of the
liquid.
Volume is the independent
variable because the
experimenter set it, and it
increases by regular
intervals.
Mass is the dependent variable because
the experimenter measured it and it does
not increase by regular intervals.
Mass vs Volume
0
25
50
75
100
125
150
0 10 20 30 40 50 60
Volume (ml)
Mass (
g)
All graphs MUST have
a title, of the y vs x
format.
label
units
label units
Each axis must have the appropriate label
and the symbol (abbreviation) for the units, in brackets.
Slope (m) measures the amount of steepness of a given
line segment.
Slope may be defined as the vertical change (rise) divided
by the horizontal change (run).
slope = m rise
run
y
x
2 1
2 1
y y
x x
Δ = the Greek letter delta
It means “change in . . .”
Distance vs Time
0
20
40
60
80
100
120
0 10 20 30 40 50
Time (h)
Dis
tan
ce (
km
)Pick any two points on the
line.
1 1, 0,0x y
2 2, 30,70x y
Substitute the values
into the slope formula.
2 1
2 1
y yslope
x x
70 0
30 0
km
h
2.3 km/h
Lines with a positive slope rise to the
right.
Lines with a negative slope fall to the
right.
Horizontal lines have a slope of zero.
rise =
run
yslope
x
rise =
run
yslope
x
no vertical change!
Vertical lines have an infinite slope.
∆y = zero
∆x = zero
no horizontal change!
If there is a clear
pattern among the
points, draw a best fit
line that comes as
close as possible to
most of the points.
Best fit line may be
straight or curved. (N)
(m)
read pages 472 - 477
Skill Worksheets 10 & 11