This lesson is the opening lesson in preparing students to create
their own science fair projects. It will introduce the concepts necessary
to create an experiment that uses the principles of the scientific method.
It gives the students the necessary tools to discriminate between an experiment
and a demonstration. The students need to already have been introduced to
the steps in writing lab reports using the scientific method: Purpose, Research,
Hypothesis, Procedure, Analysis and Conclusions.
Scientific Eye Series III, Lesson Eight, Variables
After completing this lesson the students should be able to
identify the independent variable, dependent variable and controls in an
experiment; and design simple experiments that use controls to isolate a
single independent variable and measure the resulting dependent variable.
Each group of two to four students will need :
Have a classroom source of:
- paper towels
- 1 graduated cylinder
- 7 clear plastic cups
- place to dispose of the wet sand.
Have the student groups fill two cups with marbles, two cups
with fine, dry sand and three cups with water. Have the groups count how
many marbles are in each of the two cups. Record group results on the board.
Then ask the students to discuss why there are differences in the answers.
The focus for viewing is a specific responsibility or task(s)
students are responsible for during and after watching the view to focus
and engage students' viewing attention. Assign each student group a focus
for viewing activity an tell them that they will be standing and presenting
their focus for viewing to the rest of the class after viewing the video
segments. Group one should identify independent variables shown in the video.
Group two should identify dependent variables in the video. Group three
should identify controls used in the video. Group four should identify the
various devices used to measure dependent variables
Teacher note: Several segments are skipped because
they do not deal directly with variables or controls and could side track
or confuse students who are approaching the topic for the first time. Because
of the introduction of vocabulary terms not included in the video, the video
needs to be stopped frequently and the students assisted with associating
the vocabulary terms with the words and scenes in the video.
BEGIN playing the video from the opening credits. PAUSE
the video when the screen shows a picture of a metronome and the narrator
says "Look and listen carefully, what's changing here?" mute the
sound on the TV and ask the students to focus on what's changing. RESUME
playing the video with the sound off. PAUSE the video when the screen
changes to a frying pan and have the students discuss what they interpret
to have been happening in the segment. REWIND to the beginning of
the metronome segment and play it again with the sound on. PAUSE
the video when the screen again shows a frying pan. Have the students discuss
how their explanations compared with the narrators explanation. Help the
students associate the term "cause" with the vocabulary term "independent
variable" and the term "effect" with the vocabulary word
"dependent variable. FAST FORWARD the video to a screen
showing the word "Look" and RESUME playing. PAUSE
the video when the screen shows three balloon and the narrator says "Which
ones were important?". Have the students identify the three variables
assisting them with using cause and effect to determine the independent
and dependent variables. These are color and size (independent variables)
and loudness of the sound of the balloons bursting (dependent variable).
RESUME playing the video. PAUSE the video when the narrator
says "There's some vinegar in the left-hand beaker." Have the
students identify the things in the demonstration on the screen that are
the same. Help them associate these with the vocabulary term "controls".
RESUME playing the video. PAUSE when the screen shows bubbles
in the left had beaker and point out the independent variable (the vinegar
vs. water) and the dependent variable (fizz vs. no fizz). RESUME
playing the video. PAUSE when the screen shows a girl holding a bag
of molasses and the narrator says "How would you find out how fast
the bag goes?" Initiate a discussion about the connection between the
dependent variable and measurements. In a good science fair experiment there
are measurements of the dependent variable, not a simple statement of this
brand wins. RESUME playing the video. PAUSE when the screen
shows a sky with a sun and the narrator says, "Elapsed time is a variable."
Initiate a discussion of ways to measure time as a variable. Discuss how
elapsed time can be an independent variable or a dependent variable relating
it to cause and effect. FAST FORWARD the video to where the
Scientific Eye logo appears on the screen and RESUME playing. PAUSE
where the screen shows the man measuring the bean and the narrator says,
"And how long do you think it would take?" Have the students identify
the possible independent variables and list them on the board. Have each
group choose one variable and identify how they could use controls to isolate
their chosen independent variable and how they would measure their resultant
dependent variable. STOP the video after the narrator says "Why
is fairness important?" and the Scientific Eye logo appears on the
Have the student groups predict which "full" cups
have the greater total volume of matter in it, the sand cups or the marble
cups. Have them write a procedure to prove or disprove their hypothesis.
Be sure that the identify the independent variable, the dependent variable
and any controls that they use. Check for utilization of the lesson concepts
in the design of their experiment by questioning the groups about their
procedure. Have the student perform their experiments and record the results.
Be sure they unit label the measurements they take to record their dependent
variable results. Have them record their results on the board and discuss
the results of the class as a whole.
If time permits, have the groups make an extra copy of their experiment
and exchange experiment plans with another group. After performing the other
group's experiment, have them critique the experiment plan. This will give
them experience needed to evaluate their own work. These critiques should
be included in the final scores for the activities. This activity lends
itself easily to inclusion in a portfolio.
Have the students attend the Mentors program meetings sponsored
by Science Pioneers to provide them with real scientist mentors as advisors
for their science fair projects. Science Pioneers has offices at Midwest
Research on Volker Boulevard in Kansas City, Missouri.
Have the student groups prepare a lesson on designing an experiment to show
to a group of younger students. This is particularly useful if you have
eighth grade students in a middle school present ideas to a group of sixth
graders who are entering science fair for the first time.
Have student groups prepare a sample science fair display from
their experiment and have them present it at the next P.T.A. or S.A.C. meeting
for parents to get an opportunity to interacts with the students about their
science and math experiences. This will be particularly useful if your students
are expected to explain their project to the judges at your local science
Language Arts and Science:
Have your students as a class videotape a "how to" video for next
year's class to see explaining how to design a science fair experiment and
identifying the variables and controls in the experiment. This is also a
useful review and reinforcement tool for students who have been absent or
need further advice in preparing their science fair project.
Language Arts, Science and Graphic Arts:
Have groups write a "how to" manual for placement in the school
library explaining how to do a specific science fair experiment and identifying
the variables and controls in the experiment. This is also a useful review
and reinforcement tool for students who have been absent or need further
advice in preparing their science fair project.
Math and Science:
Have the groups make individual group graphs of the results of their data.
Have them then make a combined graph of the results of the class for comparison.
Social Studies and Science:
Have the groups locate information in the library about famous experiments,
for example: Millikin's oil drop experiment. Have them write make believe
lab reports about the experiments utilizing the information given in the
If your students have access to Internet or satellite broadcast exchange
programs, they will enjoy the opportunity to share their ideas with other
classes of students from other schools.
Master Teacher: Joyce M. Conner
Lesson Plan Database
Thirteen Ed Online