race cars (compressed air cars)

RACE CARS(Compressed Air Cars)

8th Grade Ind. TechMiss Check

Table of ContentsUnit 1- Understand the ProblemUnit 2- Gather InformationUnit 3-Develop SolutionsUnit 4-Implement a SolutionUnit 5-Test and EvaluateUnit 6-Redesign and Communicate

Unit 4 – ImplementA Solution

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.

Lab SafetyAlways 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.

Safety First!

During the LabWhile 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.

Working with Tools and MachinesYou 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.

Safety First!

Cleaning UpAfter 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.

Clean Up!

Lab Safety-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.

Lab Safety

Complete the Lab Safety Quiz

On the “Lab Safety” page.

Skin FrictionGlossary

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.

Skin Friction- Yellow CarThis 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

Skin Friction- Blue CarThis 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

Skin Friction- Red CarThis 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

Complete Questions Numbered OneThrough Three

SummaryFriction 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.

Rolling FrictionGlossary

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.

Yellow CarThis 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

Blue CarThis 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

Red CarThis 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

Complete Questions Numbered Four

Through Six

SummaryRolling 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.

You are ready to build Your CO2 car.

You MUST have permissionAnd be supervised by

Miss Check when using anyOf the machines.

Use the next 2 slides and forms 4-2:Implement A Solution and 4-3:Assemble The Car as guides to building your car.

Build The PrototypeIn 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.

Finish the Car1. 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”.