Transcript (IV, DV, Constants). - stroh

Today’s Agenda
Catalyst
 Variables Notes and Practice Time

I-N-D-E-P-E-N-D-E-N-T!
DEPENDENT
CONSTANTS

Exit Question
Today’s Objectives

SWBAT identify independent,
dependent, and constant
variables in a scientific
experiment.
Experimentation

Key Point #1: A proper experiment
always has an independent
variable and dependent variable.
The
purpose of an experiment is to
test how changing ONE THING affects
something else.
Variables
Independent Variable: what causes the
change we are measuring (acts
independently)
 Dependent variable: what gets changed
(depends on other things)
 Remember!!!!

 Variables
are always CATEGORIES of things:
time, amount, frequency, size, type
 Variables are NEVER specific things!!!
Demo

http://www.unitedstreaming.com/
videos/dsc/externalApplications/
virtual_labs-es/Plants/index.html
Teacher Models

Scientists have discovered something
shocking: if you eat a lot of hamburgers,
then you will gain fat. What is the
independent variable?
A.
B.
C.
D.
Eat a lot of hamburgers
Type of hamburger you eat (McDonald’s,
Wendy’s, Burger King, etc.)
Amount of hamburgers you eat
How much weight you gain
Teacher Models

Well-rested students learn more in school.
So, Ms. Stroh believes that starting school
later would increase test scores. What is
the dependent variable?
A.
B.
C.
D.
Starting school later
Well-rested students
Time that school starts
Test scores
NEW PROCEDURE!
WHITEBOARDS!
Whiteboard Practice

When Ms. Stroh says “GO!”
 Send
one member of your group to get
whiteboards, erasers, and markers for
everyone (back lab bench)

Hurry! Remember, we want to stay under
3 minutes of transition time!
Whiteboards 1

Ms. Stroh believes that the more you
study, the better grades you’ll earn.
What is the independent variable?
A.
B.
C.
D.
Studying more
Amount of time you study
Grade earned
Type of test
Whiteboards 2

Shanel is always cold in class. She
hypothesizes that if she wears many
layers of clothing to school, then she will
be warmer. What is the dependent
variable?
A.
B.
C.
D.
Number of layers Shanel wears
How warm Shanel is
Temperature of the room
Shanel will be warmer
Whiteboards 3

Ms. Stroh’s students want to test how
easily bought off she is. Students who
give her an apple get a “C.” Students
who give her candy get an “A.” What is
the independent variable?
A.
B.
C.
D.
Type of food given to Ms. Stroh
Apples and candy
“A” on the report card
Report card
Whiteboards 4

Tashica hates cooking, but loves listening
to music. She believes that if she listens to
music while cooking, then she will cook
more often. What is the dependent
variable?
A.
B.
C.
D.
She will cook more often
Listens to music while cooking
Frequency that Tashica cooks
What Tashica listens to
If you’re having trouble…
WRONG







4 minutes
26 mg of baking soda
Lifting weights every
day
Medium t-shirts
Bullfrog
16 candles
Never gets sick
RIGHT







Time to get dressed
Amount of baking soda
Frequency of lifting
weights
Size of t-shirts
Type of frog
Number of candles
Degree of health
Review

Ms. Stroh believes that the more you
study, the better grades you’ll earn.
What is the independent variable?
A.
B.
C.
D.
Studying more
Amount of time you study
Grade earned
Type of test
Review

Shanel is always cold in class. She
hypothesizes that if she wears many
layers of clothing to school, then she will
be warmer. What is the dependent
variable?
A.
B.
C.
D.
Number of layers Shanel wears
How warm Shanel is
Temperature of the room
Shanel will be warmer
Review

Ms. Stroh’s students want to test how
easily bought off she is. Students who
give her an apple get a “C.” Students
who give her candy get an “A.” What is
the independent variable?
A.
B.
C.
D.
Type of food given to Ms. Stroh
Apples and candy
“A” on the report card
Report card
Review

Tashica hates cooking, but loves listening
to music. She believes that if she listens to
music while cooking, then she will cook
more often. What is the dependent
variable?
A.
B.
C.
D.
She will cook more often
Listens to music while cooking
Frequency that Tashica cooks
What Tashica listens to
Guided Practice Worksheet
10 minutes to complete
3 minutes to compare answers
KEEP THIS to help you with
homework tonight

Constants

Key Point #2: Everything but the
independent and dependent variable
must be kept constant.
 Constant:
 If
variable we keep the same
many different things change at once, we
don’t know what causes the change!
Example

Let’s say we want to design an experiment to
determine what causes the Hornets to win games.
Number of
games that
Hornets win
Try this one! Answer in notes…

Travie McCoy hypothesizes that if he write
more songs about being rich, then he will sell
more CDs because his listeners also want to be
rich.
 What
is the IV?
 What is the DV?
 What are the constants?
 Remember,
variables are
CATEGORIES.
If Travie write more songs about being rich, then he will sell
more CDs because his listeners also want to be rich.

IV
Number of songs about being rich
 How often Travie sings about being rich
 Amount of times Travie sings about money


DV
Number of CDs Travie sells
 How many CDs Travie sells


Constant
Amount of money CDs cost
 Number of tracks on each CD
 How good each CD is

Practice
You want to know when in the year there are the most
love bugs. Every night, you record how many love
bugs you find outside.
IV =
Time of year
(season/month)
DV =
Amount of fireflies
Constant =
Practice

Maria needs to run a 6 minute mile to pass PE. She
believes that if she runs every day, then she will be
able to run faster.
IV =
Frequency that
Maria runs
DV = Mile time
Constant =
Practice

Students of different genders were given the same
puzzle to assemble. The puzzle assembly time was
measured.
IV =
Type of gender
DV =
Time to assemble
puzzle
Constant =
If there are more students,
then there will be more school
bus drivers.
IV =
Amount of students
DV =
Number of school
bus drivers
Constant =
What depends on what?
IV =
Amount of sugar used
DV =
Number of beignets
sold
Constant =
If the amount of sugar used
on beignets decreases, then
less beignets will be sold.
If the Saints win more games, then they will
attract more big name players.
IV = Number of games won
DV = Number of players
attracted
Constant =
Conclusion

A proper experiment always has an
independent variable and dependent
variable. Everything but the independent and
dependent variable must be kept constant.
 Independent
Variable: what causes the change we are
measuring
 Dependent variable: what gets changed

Constant: variable we keep the same
Exit Question

Let’s say you want to figure out if drinking
milk actually makes you taller. So you drink a
glass of milk every day, and record your
height every day.
1.
2.
3.
What is the independent variable?
What is the dependent variable?
What are at least two constants?
HW: IV, DV, Constants Worksheet!