TOPIC: Scientific Method
Aim: Review the rules of graphing.
Do Now: next slide
HW: Ditto – Identify Controls and
Variables Sections A and B
Students wanted to determine if PG
Growth Solution affects plant growth.
Two groups of 5 plants of the same
species we kept in identical conditions
except the plants in Group A were
given PG growth solution every 3 days.
The plants in Group B were not given
the solution.The heights of the plants in
both groups were recorded at the
beginning of the study and at the end of
a 3 week period.
To investigate the effect of a substance
on plant growth, 2 bean plants of the
same species were grown under
identical conditions with Substance Z
added to the soil of one of the plants. At
the end of 2 weeks, the plant grown
with Substance Z was 15.5 cm tall. The
plant grown without Substance Z was
9.2cm tall. The researcher concluded
that the presence of Substance Z
causes the plants to grow taller.
Why are
graphs
used?
• Visually display
data measured
• So data can be
easily understood
Parts of a
graph
• Relationship:
As the “indep. variable” increases, the
“dep. variable”...
10 23 39 48 64 77 87 98
INCORRECT!!!
The scale has no CONSISTENT interval.
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
CORRECT!!!
The scale has a CONSISTENT interval.
It goes by 5’s.
10
15
20
25 30 35 40 45 50
55
INCORRECT!!!
The number of boxes between the numbers
is not the same.
50
55
60
65
70
75
80
85
90
CORRECT!!!
The number of boxes between numbers is
the same.
There is a consistent interval.
20
40
60
80
100
120
CORRECT!!!
There is a consistent interval.
The number of boxes between each number
is the same.
0
10
20
60
65
70
CORRECT!!!
No consistent interval.
75
80
85
90
0
10
20
60
65
70
75
80
85
90
INCORRECT!!!
The numbers are not beneath the lines. They
are between the lines.
3 main
1.Bar graph
graphs
used in
science
2. Circle Graph (Pie Chart)
3. Line graph
12
14
14
15
Students of different ages were
given the same jigsaw puzzle to
put together. They were timed
to see how long it took to finish
the puzzle.
What was the independent
variable?
• Ages of the students
What was the dependent
variable?
• The time it to put the puzzle
together
• The time was measured by
the scientist