Table of Contents
Unit 1- Understand the Problem
Unit 2- Gather Information
Unit 3-Develop Solutions
Unit 4-Implement a Solution
Unit 5-Test and Evaluate
Unit 6-Redesign and Communicate
In this activity you will:
--Learn about friction.
-Implement a solution for the CO2 Car Design project.
-Cut out, shape, and finish your car.
-Keep safety in mind while building your car.
Always keep safety in mind. Safety is staying out of harm’s way. Follow all of our
specific lab safety rules. Always read and follow lab safety rules. Ask questions when
you do not understand what to do.
While you are working in the lab, use common sense. Make sure to:
- Follow all of the instructions
- Pay close attention to what you are doing at all times
- Keep your work areas clean and tidy at all times
Always read the instructions before beginning the activity.
Carefully follow all of the written and oral directions. If you are in doubt, ask
the teacher for instructions.
Wear eye protection when needed.
Stay focused on your task, especially when you are using tools or machines.
And be aware of the people around you.
If any injuries do happen in the lab, tell your teacher immediately.
You may have the chance to work with tools and equipment that need to be handled
safely.
Wear eye protection when working with sharp tools or machines with moving parts.
When using machines and tools, make sure that you are not wearing any loose
clothing or jewelry, and that your hair is tied back securely.
Keep hands and fingers away from all moving parts.
Handle sharp instruments with extreme care. Always point them away from your
body and cut material away from your body.
Review a machine’s safety rules before you turn it on. Remember to ask your
teacher for help if you are not sure.
After your work is done, turn off any machines that you are using. Clean up your work
area and return all tools to the proper place.
Remember the number one safety rule: Follow the rules and ask questions if you are not
sure what to do.
-Always make sure to point sharp instruments and cut materials
AWAY from your body.
-After your work is done, make sure to turn off machines, clean up
your area, and return tools to their proper places.
-Keep hands and fingers away from blades and moving parts.
-Before you turn on a machine, make sure to read or review the
safety rules and instructions.
-If an injury were to occur you need to immediately turn off the
machine and notify the instructor.
Friction- When two surfaces rub together, the irregularities of
the surfaces catch again each other. Friction is the force one
surface exerts on the other when they rub together.
Skin Friction- Skin friction is friction that takes place in a thin
layer of air surrounding the surface of an object. Skin friction is
caused by the collision of particles between the object and the
air.
** The rougher the surface of the object, the greater the skin
friction.
This car has a standard body design and is made from light
materials. Because the car has not been sanded, the finish is very
rough.
2.784 seconds
This car has a standard body design and is made from light
materials. The car has been sanded a small amount. Some areas
that are smooth, while others are still rough to the touch.
2.453 seconds
This car has a standard body design and is made from light
materials. The car is very smooth and well-sanded. There are no
rough areas.
2.187 seconds
Friction is the force one surface exerts on the other when they
rub together. It is a type of drag.
Skin friction is a friction that is caused by the collision of
particles between the object and the air.
To reduce skin friction, sand the car until it is smooth.
Friction- Recall that friction is the force one surface exerts on the
other when they rub together.
Rolling Friction- Rolling friction occurs when an object rolls over
a surface. The most common place where rolling friction occurs
on a race car is between the axles and the body.
This car has standard body design and is made from light
materials. The axle is perpendicular, or at a 90 degree angle to
the car body. The axle has been lubricated, or oiled.
90 degrees
Race Time – 18.57 seconds
This car has a standard body design and is made from light
materials. The axle is not perpendicular, or at a 90 degree angle,
to the car body. The axle has been lubricated, or oiled.
Race Time- 28.47 seconds
This car has a standard body design and is made from light
materials. The axle is perpendicular, or at a 90 angle, to the car
body. The axle has not been lubricated, or oiled.
90 degrees
Race Time – 19.67 seconds
Rolling friction is the friction that occurs when an object rolls over
a surface.
To reduce axle rolling friction, make sure the axles are free from
burrs or scratches, are perpendicular to the car body, and are
lubricated.
Use the next 2 slides and forms 4-2:Implement A Solution and
4-3:Assemble The Car as guides to building your car.
In this activity, you will build your prototype car. Building a prototype
involves several steps.
1. The first step is to prepare to cut the car.
a. Use scissors to cut out the car views from your Design Sketch.
b. Use a marker to trace the cut-outs onto the car body.
c. And then mark the axle holes.
2. Next, create axle holes on the car body. Axle holes must be exactly
parallel, or even, with the bottom of the car body.
3. Then, cut out your car. You will use the scroll saw to do so.
4. It is a good idea to make sure your car meets the Race Car Specifications
before continuing.
1. The next step is to shape the car.
2. Then reduce skin friction. You can reduce skin friction on your
car by sanding the car until it is smooth.
3. Then you assemble the car. Assembling the car involves
installing the wheels and axles correctly. It involves making
sure the wheels and axles have good rolling friction.
4. Fasten the eye hooks on the bottom of the car. The eye hooks
will help keep the race car driving in a straight line.
5. After the car is finished, roll it gentry across a table or flat
surface to check if the wheels roll smoothly but are not loose.
Congratulations! You have completed Unit 4- Implement a Solution.
You will now move onto Unit 5.
The power point is titled “Unit 5 – Test and Evaluate”.