Making an electric car is a
mechanical engineering challenge often used as a competition for
students from 5th grade to 8th grade.
An electric car is driven by a
DC electric motor, powered by one or two batteries.
Transmission of force from the
motor to the car axle is accomplished using two pulleys and
one rubber band acting as a belt. A simple switch made of a
paper clip is used to connect or disconnect the circuit.
Wheels are made of larger pulleys with rubber rings as
tires. The car chassis is mad of a plastic board, reinforced
by wood blocks and eye screws that will also support the
axles of the wheels.
Some students may prefer to buy all
the parts separately and cut all
the woods themselves and design their own car; however, most
students and teachers prefer to get all the parts in a kit and make
changes as they need.
With this project students can explore:
- A simple propulsion method
- Basic gluing techniques and design concepts
- Concept of stored chemical energy energy
and converting it to mechanical energy
- A simple electric circuit
Kits usually come with parts, cut to size and ready to use.
The picture bellow shows the materials you usually
find in an Electric Car Kit from MiniScience. Kit includes at least
4 wooden parts and one plastic board, cut to size in addition to the
4 pulley wheels, 4 tire rings, battery holder, one transmission
pulley, electric motor, rubber bands, motor mount, screws, brass
paper clips and eyelets.
Before using the kit please verify the content
with the parts in this picture.
In addition to the kit
parts you will need:
- White glue or wood
- Grip Pins
- Sand Paper (Medium
- Latex Paint
During construction of the electric vehicle, students
can experiment and
comprehend methods of power transfer, using glue, measurement, making a simple
electric circuit . It is up to the teacher to make sure this background information is
provided to students in some manner.
Before invention of gas
engines, cars were pulled by horses or other animals.
Now gas burning engines are the most popular drive in
cars. There are concerns about the air pollutions caused
by gas engines and electric cars are entering the market
in a fast pace. Electric cars rely the electrical energy
stored in batteries, so they will not cause any air
Because of the limited
amount of electricity stored in batteries, electric cars
must be made very light so they can transfer a longer
distance with a limited amount of energy.
1. Cut the 30cm basswood piece to
make two lengths each 7cm long.
(You may have this already
cut to size in your kit)
2. Cut the 30cm piece of 4mm dowel to make two lengths each 10cm
(You may have this already
cut to size in your kit)
3. Lay out the components of the kit and cut the plastic tubing into
4 equal pieces.
4. Connect the two wooden blocks to the plastic base using four
screw eyes. The screw eyes are placed at an equal distance from the
smaller end of the base and at a distance from the edge to
accommodate the plastic tubing. A sharp object may be required to
start the process of screwing the eye through the plastic and into
5. Place the axle dowels through the screw eye axle holders:
6. Fit the small pulley onto one of the axles and then fit a large
pulley onto each axle as a wheel. Put a piece of plastic tubing
between the screw eye and the wheel and ensure that the tubing is
not too tight against the eye. Finish off the wheel by fitting an
O-ring around each pulley.
7. Using the paper clip as a guide poke the brass fasteners through
the plastic base and secure them so that the heads of the paper
clips are on the side that has the wooden blocks, not the screw
eyes. Place the paper clip under one of the brass fasteners.
8. Cut the red wire into two and strip 1cm from each end. Also strip
1cm from each end of the black wire. Connect one end of a red wire
to the positive end of the battery holder and the other end of the
wire to the brass fastener that is connected to the paper clip.
Connect the second red wire to the second brass fastener. Connect
the black wire to the negative end of the battery holder. Notice the
location of the small pulley.
9. Position the gray motor clip onto the base as shown in the
Push the small black motor pulley onto the shaft of the motor and
connect its two terminals to the red and black wire. Position the
motor into the motor clip and using an elastic band connect the
small motor pulley to the small red pulley as shown above.
When the paper clip switch is closed the electrical circuit is made
and the electric car will move. Crossing the elastic band will cause
the car to move in the opposite direction.
Electric Car project:
Construction of an electric car is
an engineering/ technology project. When you try your car in a race,
the one that is built with more precision and more considerations,
will be the fastest. To build and use this car as a science project,
you may find a research subject that is closely related to that. For
example you may try to find out:
Which battery brand provides the
most power to your car?
Make a slight slope (about 10%) and
use your car to carry some load up the slope. Find out what is the
maximum weight that can be carried by your car. You may use pennies
as weight. Each penny is about 3 grams.
Repeat your test with different
batteries and record your results in a table like this:
|Make Bar Graph:
You can also use the results
to make a bar graph. Bar graph can be used to present your
Make one vertical bar for
each battery brand you test. The height of each bar will be
the amount of load (weight) the car could carry with that
brand of battery. For example you may make a bar 75mm tall
indicating to show that the car was able to carry 75 grams
with that specific battery.
|If you don't
have this kit, you can order it now! It is
available both as a single pack and class pack.