Go Car, Go!
Created for SPICE by Donovan German
KEY QUESTION(S): How are momentum and inertia affected by mass?
SCIENCE SUBJECT: Physical Science
GRADE LEVEL: 6-8
SCIENCE CONCEPTS: Newton’s First Law, momentum, velocity, acceleration
OVERALL TIME ESTIMATE: 3-5
50 minute class periods
LEARNING STYLES: Visual, auditory, and kinesthetic.
VOCABULARY:
Acceleration – rate of change of velocity
Inertia – measures an object’s tendency to remain at rest or to stay in
constant motion
Mass – quantity of matter in an object and a measure of the object’s inertia
Momentum – product of mass and velocity
Newton’s First Law – States that an object at rest or moving at a constant
speed in a straight path continues to do so until a net force acts on
it.
Velocity – a rate of change of displacement; includes both speed and
direction
LESSON SUMMARY: In this lab students will build a balloon powered car, without
directions, using the materials provided by the teacher. Students will evaluate
their cars for velocity, acceleration and momentum. After class races, students
will reevaluate their cars and suggest changes for improvement.
STUDENT LEARNING OBJECTIVES:
The student will be able to...
1. building a working balloon powered car
2. calculate velocity
3. calculate momentum
4. calculate acceleration
5. evaluate their car design based on its velocity, momentum & acceleration.
MATERIALS:
Per student:
Worksheet (located at end of file)
Per lab group:
1 inch thick Styrofoam board (car body)
1-2 balloons
wooden skewers (axels)
wire hanger pieces (axels)
ziplock bag (used to hold car and pieces during building process)
Meter sticks
Stopwatches or watch/clock with second hand
Calculators (optional)
Per class:
Bobbins
Wooden beads (both spherical and flat rounded beads)
Straws
Pipe cleaners
Rubber bands
Duct tape
masking tape
Hot glue gun
Foam balls
Markers
Any other items you have on hand that could be used in car building
Balance or electronic scale
Teacher:
Exacto knife (for cutting Styrofoam)
ADVANCE PREPARATION: Copy worksheets for students. Collect enough
materials for students to build cars.
PROCEDURE: Divide students into lab groups to build cars. The only requirement
for building the cars is that the body must be made of Styrofoam and can be
powered by no more than 2 balloons. Stand back and let them go. Have students
make a pattern for their car body and bring it to you to cut out of the Styrofoam
with an exacto knife. After the cars have been built, students should go through
the worksheet with their car. Once everyone has done this, race the cars. After
the races, have students think about how they could use this information to improve
their car’s performance.
SUNSHINE STATE STANDARDS:
SC.C.1.3.1. – knows that the motion of an object can be described by its
position, direction of motion, and speed.
SC.C.2.3.2 – knows common contact forces
SC.C.2.3.5 – understands that an object in motion will continue at a
constant speed and in a straight line until acted upon by a force and that an
object at rest will remain at rest until acted upon by a force.
SC.H.1.3.5 – knows that a change in one or more variables may alter the
outcome of an investigation.
Go Car, Go!
Inertia is Newton’s first law, which states than an object at rest will remain at rest unless
acted upon by an outside force. Alternatively, inertia can be understood as an object in
motion staying in motion unless acted upon by sufficient force to stop it. If you think
about it for a minute, you can discern that inertia really refers to the mass of an object,
because heavier objects are more difficult to get moving and once they are moving, they
are more difficult to stop.
Momentum is how much force a moving object exerts as a function of its mass and
velocity ( = mass x velocity). So, at a given velocity, a heavier object will have more
momentum than a lighter object. Acceleration is the change in velocity that occurs over a
given length of time [i.e. (v2 – v1)/time].
Today, you will build a balloon powered racing car. You will have a slew of materials
from which to choose to make your car. It is up to your group to design the body shape
and size of the car and determine what you will use for wheels and axles to make your car
work. There are four stipulations:
1) You must use different wheel types for each axle. All of your wheels cannot be
the same.
2) No more than two balloons per car.
3) You must use a piece of Styrofoam board for your car body.
4) You must have a platform on which to tape your balloon on top of your car. That
is, you need a piece of wood or metal attached to the top of your car that will
allow you to tape your balloon to the top of the car. Tape doesn’t stick well to
Styrofoam.
Otherwise, go to town! See what you can come up with and enjoy the process.
Materials for your lab group:
Ziplock bag
Meter stick
Stop watch or clock/watch with second hand
Calculator (optional)
1-2 balloons
materials for car pieces
Procedure:
1) Build your car. The first step is to design your car body. The body must be made
from Styrofoam board. Make a pattern of the shape you want and take it to the
teacher. The teacher will cut your body out of the Styrofoam board for you.
Select items to make your car from those supplied by your teacher. Make sure
your car rolls freely when pushed.
2) Record the mass of your car __________________________ g.
3) Once your car is complete, obtain a balloon and test your car. Inflate your balloon
and affix the balloon to the platform on the top of the car with tape such that the
balloon opening faces the back of the car. Remember, the balloon is the source of
force to move the car so make sure it blows your car in the right direction.
4) Let the balloon go and see if your car will move.
Did it work? ________. If so, proceed to number five. If not, what are you going
to do to remedy the situation? (Write down here what you will do.)
5) Set up a space on the floor in the classroom where you can let your car travel
freely.
6) Test your car at least three times before beginning the experiment.
7) We will determine the velocity and acceleration of your car as it moves across the
floor while the balloon deflates. Start the timer when you release the balloon and
stop it when the balloon is completely deflated, NOT when the car stops moving.
Use centimeters for the distance (displacement) and seconds for the time. Test the
car three. Record the time and distance in the table below for each trial. .
Remember to include your units! We will calculate the velocity and acceleration
in the next steps
Balloon Car Data
Trial
Time
Distance
1
2
3
Average
xxxxxxxxxxx
xxxxxxxxxxx
Velocity
Acceleration
8) Calculate the velocity for your car for each trial. Fill in the answers on your table
above. Show your work below.
V = d/t, where V = velocity, D = distance (displacement), and t = time.
9) Calculate your average velocity and fill in the answer on your table. Show your
work below.
10) Calculate the acceleration for you car for each trial. Fill in the answers on your
table above. Show your work below.
A= v2 – v1
t
where a = acceleration, v2 = velocity from table, v1 = 0, t = time
11) What is the momentum for your car? ( = mass x velocity). Show your work
below.
12) The whole class will now engage in races for highest velocity and most
momentum. Follow your teacher’s rules. Did your car win any of the events?
Why or why not?
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