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Aerodynamics has a lot of the part in this because it helps decreasing the air pushing back on the car.

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved:

Mass: Obviously, this is how large and heavy the car is. Simply put, the less weight your dragster has, the faster it will go. This is the most important factor that will figure into your design. Keep it light!

Thrust: The gas escaping from the CO2 cartridge in the car. We'll cover this in a bit.

Friction: The second most important fact you'll face. Because the dragster has parts moving against one another, friction is created. You can help reduce it by making sure the axles are free to rotate, and that the wheels and tires are not rubbing on the car body.

Drag: Here's where aerodynamics come into play. As an object moves through the air, it is met with air resistance as speeds increase. This air resistance pushes against your CO2 car and prevents it from going as fast as it could in a vacuum. You can't completely ever reduce drag, but you can help reduce it by building a more aerodynamic car, but those are more difficult to create.

[source: Virginia Tech University Technology Education]

Of these three factors, drag is the toughest one to test for. It's hard to tell with the naked eye just how much drag your CO2 car will face. For that reason, you may want to opt for a wind tunnel. Believe it or not, there are small wind tunnels available designed to test models, like Pitsco's AirTech X-Stream Wind Tunnel [source: Science of Speed].

By putting your car into the wind tunnel and putting a fog vapor into the air stream, you can track how air flows over the car's body. You want a smooth flow of air free of swirling currents called eddies. If you have too many of those, you may want to use sandpaper to smooth out the design, or go with a new one altogether.

Up next, we'll examine what makes CO2 dragsters go: The power of carbon dioxide propulsion.

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved: Mass: Obviously, this is how large and heavy the car is.

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As a car moves faster, forces can push upward on the car and cause it to flip over. The best way to avoid this is to add weight to the front of the car to reduce lift.

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So you here most probably after watching the video on YouTube (if not, you can watch h﻿﻿﻿ere) and are wondering what made the car lift off the road while moving at high speed and the devastating effect it has on the car. We are going to cover alot about different types of car spoilers and how they help in stabilization of the car.

So what went wrong after all?

Let's discuss this important point...

Vehicles that run at high speeds often encounter control problems because, at high speeds, the increased airflow creates too car lift, which can be especially dangerous when the vehicle makes a turn or when it goes for a steep section of the road, as this can make it fly off the road and lose control.

In the figure above, the longer and greener the arrow is, the faster the air flows over the car. This shows airflow from the front of the car, but the same areas where air flows quickly when the car is going straight are the same areas where air flows quickly when the car is yawed.

What's the reason?

To put in simple terms.

A car is shaped like an airfoil (like a wing of a bird or plane). As the car accelerates the air moves faster around it and you get a vertical force that lifts it from the ground. As the uplifting force increases, it reaches a point where the force of gravitation gets negated and the tip of the car gets lifted up. Now the moving air gets blocked in front of it and instead of moving around it and air pressure increases. It pushes against the (rising) bottom of the car, the results is shown in the screenshot below.

A car is shaped like a airfoil (like a plane) if proper aerodynamics is not considered, it can lift from the ground !

Practically any shape will fly once there's enough angle of attack and forward speed, whether it's wing-shaped or not. What went wrong here especially in the above screenshot is some combination of a poorly-designed rear wing and the various other torques acting on the car got the front end up a little-- and once it's angled up, it's going up.

Solution to the problem?

This is interesting.

We can break down the solutions into four...

1. Add weight.

Yes that's correct, one practical solution would be to increase the weight of the vehicle to keep it on the ground. However, this causes the car to slow down and consume more fuel. Additionally, when it comes to racing cars, manufacturers cannot afford to add additional weight that can reduce the car's speed. Therefore, carmakers need a way to counter the lift without adding more weight, thus we would require a solution to the solution.

2. Design Improvement.

To put it straightforward - don't build a car shaped like a wing.The design of the car decides many things. For example, it is entirely possible (and desirable) to actually generate downforce just by going faster. This is called ground effect and some aerodynamics car design tips might include making the car low enough such that air goes faster under the car and not over it, so Bernoulli's principle actually sucks the car to the ground rather than lifts it up.

So what is Bernoulli's principle by the way? Its states that an increase in the speed of a fluid occurs simultaneously with a decrease in the pressure exerted by the fluid. The principle is named after Daneil Bernoulli.

3. Add Diffusor.

With modern ways of simulation and testing you can design the bottom of your car in a way, that you get a zone of low air pressure underneath your (moving) car and you "suck your car onto the street"

Spoilers are added to cars and other vehicles to make them more aerodynamic.

The advantages of this can be seen very readily. Instead of having a heavy car, which is slow, or having a very light car, which can slide away easily, you now have a car that sticks better the faster it goes.

Sounds perfect, right? There is one catch.

Every time a wing generates lift (or a spoiler generates down force) it also generates drag. Drag is the natural reaction of the fluid (air) to resist motion through it (the car). Drag is bad, because it slows down the car. So, more down force is good... but too much down force = too much drag, which is bad. Very very high performance sports cars, like Le Mans or F1, have a ratio called the 'lift/drag' ratio. The car designers try and maximize this so that the car has just enough force to get around the corners, but not so much that they are too slow.

So what are the types of spoilers available?

There are various types of spoilers on car available today in various designs and types of materials. However, perhaps the best way to categorize spoilers is where they are mounted on the vehicle, as this also determines how they can improve a vehicle's performance. The chart below summarizes the common types:

The Many Benefits of Spoiler on Car

Installing a spoiler on a vehicle provides a variety of benefits for owners. The main benefits, perhaps, are for better traction and to add a sporty look, but also include other advantages, such as increased fuel efficiency, added visibility, reduced vehicle weight, and braking stability.

Conclusion

Adding a spoiler to a car is not all about looks. While many people may sneer at fancy spoilers on street cars, these do provide other advantages that changes the aerodynamics of a car.There are many different types of spoilers today, but they can be best classified according to where they are positioned on the car

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Why do cars generate lift ? [ANALYSIS AND SOLUTION]

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So you here most probably after watching the video on YouTube (if not, you can watch h﻿﻿﻿ere) and are wondering what made the car lift off the road while moving at high speed and the devastating effect it has on the car.

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aerodynamic drag is caused by turbulence which effects speed a lot and slows it down

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Most people believe that weight affects speed, but it doesn't. It affects momentum. Weight affects the speed going down a ramp (thanks to gravity), but friction and and it's mass is what helps your car speed up or down once it leaves the ramp.

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Preparation and points to note
Make sure the students have enough uninterrupted space for the model cars to roll long distances without interruption. A smooth surface works best; carpets create friction*.

The students could do the graphing on a computer spreadsheet programme.

In this activity, students need to make sense of information, draw on their own experiences, and debate their ideas, all of which use and further develop the key competency thinking.

The students will have prior knowledge, ideas, and misconceptions about mass, height, and distance. Encourage them to test and argue their ideas and to fi nd evidence or counter-arguments via their investigations. Students need to be explicitly taught the norms of mathematical argumentation and that it's the ideas that are competing and being evaluated, not them.

Although the students may know by now that weight doesn't affect speed (see Flying High, pages 4-6), they may not realise that mass does affect momentum. Weight affects speed down the ramp (the pull of gravity), but it's the mass (and friction) that affects speed after a car leaves the ramp. Heavier cars have more momentum, so they travel further, given the same amount of friction. Note that in the Swing Time activity, the pendulum speed was also not affected by weight, but heavier pendulums have more momentum and continue to swing for a longer time.
Points of entry: Mathematics
All the aspects that the students suggest will be variables. Prompt them to consider other variables and classify them as independent or dependent.

Make sure that everyone understands the defi nitions of independent, dependent, and controlled variables.

Measurement should be discussed in conjunction with accuracy, units, and error. Instead of grams or kilograms, the students can use informal units for mass, for example, identical small weights. Make sure they understand why the units must be uniform.

Discuss why averages (means) are useful when analysing data. It is unwise to rely on the results of just one measurement because of conditions and human error. Discuss averages in relation to activities that are naturally prone to variation, for example, traffic, air temperature, attendance, or driving speed, where any one measurement will not give you a good picture of overall conditions.

Ask the students to think about why they are asked to graph their results and about what type of graph to use. What advantages does a graph have over a table? Why do we use different representations?
Points of entry: Science
Remind the students what it means to "think like a scientist". This activity reintroduces the scientifi c inquiry method (see page 5). Ensure that the students are comfortable with the cycle of hypothesis, design of experiments, data gathering, and conclusion.

Ask: What factors will affect distance? How can we test their effect fairly? Have the students invent experiments, for example, ask How could you test whether wheel size affects how far a car travels? For each test, prompt the students to determine the independent and controlled variables. (The dependent variable for these tests should always be the distance travelled.)

Challenge the students to justify why they think a particular variable may be important. This will reveal much about their science understandings. For example, air resistance increases with speed, but the cars will probably not go fast enough to make air resistance important. Variables that could spark students' thinking include starting location, wheel size, axle size, lubrication, wheel shape, wheelbase, and the car's length, width, and centre of gravity.

Prompt your students to identify what makes their investigation "scientific".

Relate their results back to their initial predictions: So did mass have an effect? Cognitive science tells us that people learn better when they think about how they learn. Ask How did the structure of the investigation help you make conclusions? Ask the students to think critically about how they pursued their investigation and what changes would have improved it.
Answers
Activity One
1. Ideas will vary. (Try to explain why you think your ideas will make a difference.)

2. a. Practical activity

b. The dependent variable is the distance travelled. The independent variable is the thing changed in each trial (in this case, mass).

c. Graphs will vary. However, each graph should show that heavier cars go further after they leave the ramp. A possible graph is:

3. In real life, a heavy car will be harder to slow down or stop than a lighter car travelling at the same speed (because the heavier car has more mass).
Activity Two Preparation and points to note
Changing the height will change the angle at which the ramp meets the ground. Cardboard and tape will help round any sharp angles or sudden drops. Make sure that the students have a way to secure the top of the ramp at different heights, for example, by propping the ramp up with different numbers of the same blocks (or books).

Ask the students to think about factors such as why it's important to start the car at the same spot for every trial and where the location of zero is on their horizontal scale of distance.

This is a natural opportunity to mix up groups so that the students work with a diversity of classmates. By being actively involved in a group with a common interest and focus, they are developing skills that apply to the key competency participating and contributing.
Points of entry: Mathematics
Link back to the ideas of independent, dependent, and controlled variables. On graphs, the mathematical convention is for the independent variable to go along the horizontal axis.

Ask: What other variables are contributing to the results? How do different cars behave on a ramp that is kept at the same height? Remind students to think about sources of error.
Points of entry: Science
The activity calls for multiple trials at different heights in order to get more data points (and hopefully, better accuracy).

Have the students relate their results back to their initial predictions: Did height have an effect?

Guide the students to think about weight and height together. The combination of the heaviest car on the highest ramp should clearly go the furthest. Have the students compare intermediate cases, for example, a light car on the highest ramp versus a heavy car on the lowest ramp.

As noted for Activity One, encourage the students to realise that the force of gravity pulling on a car is its weight (going down the ramp), but once the car is off the ramp, it is its mass that determines how far it will roll.
Answers
Activity Two
1. Practical activity. Your graph should show that the higher ramps caused the car to travel further.
For example, if you used up to 4 extra 10 cm blocks, your graph should show a similar pattern to this:

2. Different groups should have similar shaped graphs. However, the actual values will depend on factors such as the length of ramp, car, friction, and extra blocks used.

3. A heavy car on a high ramp should go furthest.

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Preparation and points to note Make sure the students have enough uninterrupted space for the model cars to roll long distances without interruption. A smooth surface works best; carpets create friction*. The students could do the graphing on a computer spreadsheet programme.

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Wider tires increase speed and decrease drag

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an inch of increased ride height degrades the coefficient of drag by about 10 drag counts

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As an object moves, it is met with air resistance, and this is called drag. To avoid having too much drag, you should try to minimize large dents or dips in your car design

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved:

Mass: Obviously, this is how large and heavy the car is. Simply put, the less weight your dragster has, the faster it will go. This is the most important factor that will figure into your design. Keep it light!

Thrust: The gas escaping from the CO2 cartridge in the car. We'll cover this in a bit.

Friction: The second most important fact you'll face. Because the dragster has parts moving against one another, friction is created. You can help reduce it by making sure the axles are free to rotate, and that the wheels and tires are not rubbing on the car body.

Drag: Here's where aerodynamics come into play. As an object moves through the air, it is met with air resistance as speeds increase. This air resistance pushes against your CO2 car and prevents it from going as fast as it could in a vacuum. You can't completely ever reduce drag, but you can help reduce it by building a more aerodynamic car, but those are more difficult to create.

[source: Virginia Tech University Technology Education]

Of these three factors, drag is the toughest one to test for. It's hard to tell with the naked eye just how much drag your CO2 car will face. For that reason, you may want to opt for a wind tunnel. Believe it or not, there are small wind tunnels available designed to test models, like Pitsco's AirTech X-Stream Wind Tunnel [source: Science of Speed].

By putting your car into the wind tunnel and putting a fog vapor into the air stream, you can track how air flows over the car's body. You want a smooth flow of air free of swirling currents called eddies. If you have too many of those, you may want to use sandpaper to smooth out the design, or go with a new one altogether.

Up next, we'll examine what makes CO2 dragsters go: The power of carbon dioxide propulsion.

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved: Mass: Obviously, this is how large and heavy the car is.

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You want to make sure the weight on the front and back is about the same to make sure the car can move well

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Something with less mass can move faster because it is lighter.

# data[].attributes.attachment_link.readable_text
Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved:

Mass: Obviously, this is how large and heavy the car is. Simply put, the less weight your dragster has, the faster it will go. This is the most important factor that will figure into your design. Keep it light!

Thrust: The gas escaping from the CO2 cartridge in the car. We'll cover this in a bit.

Friction: The second most important fact you'll face. Because the dragster has parts moving against one another, friction is created. You can help reduce it by making sure the axles are free to rotate, and that the wheels and tires are not rubbing on the car body.

Drag: Here's where aerodynamics come into play. As an object moves through the air, it is met with air resistance as speeds increase. This air resistance pushes against your CO2 car and prevents it from going as fast as it could in a vacuum. You can't completely ever reduce drag, but you can help reduce it by building a more aerodynamic car, but those are more difficult to create.

[source: Virginia Tech University Technology Education]

Of these three factors, drag is the toughest one to test for. It's hard to tell with the naked eye just how much drag your CO2 car will face. For that reason, you may want to opt for a wind tunnel. Believe it or not, there are small wind tunnels available designed to test models, like Pitsco's AirTech X-Stream Wind Tunnel [source: Science of Speed].

By putting your car into the wind tunnel and putting a fog vapor into the air stream, you can track how air flows over the car's body. You want a smooth flow of air free of swirling currents called eddies. If you have too many of those, you may want to use sandpaper to smooth out the design, or go with a new one altogether.

Up next, we'll examine what makes CO2 dragsters go: The power of carbon dioxide propulsion.

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved: Mass: Obviously, this is how large and heavy the car is.

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Friction is something people try to reduce in cars, but without friction, the car can't move. When a car starts to move, it's the friction between the wheels of the car and the road that makes the car move forward.

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Summary Building upon their understanding of forces and Newton's laws of motion, students learn about the force of friction, specifically with respect to cars. They explore the friction between tires and the road to learn how it affects the movement of cars while driving. In an associated literacy activity, students explore the theme of conflict in literature, and the difference between internal and external conflict, and various types of conflicts. Stories are used to discuss methods of managing and resolving conflict and interpersonal friction.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

Engineers use their understanding of the force of friction to design safe roads, tires, cars and brakes. Transportation and automotive engineers make sure that roads and tires provide the right amount of friction because friction provides traction and control for a safe driving experience, especially in icy or wet conditions. Even designing how paper is moved through a copy machine involves an understanding of friction. Engineers also reduce the force of friction between moving mechanical parts (in engines, tools, artificial limbs, etc.) so the parts run smoother and last longer.

Learning Objectives

After this lesson, students should be able to:

Explain how friction relates to the movement of cars (moving forward, stopping, turning corners).

Define friction as a force that resists the motion of an object moving relative to another object

Predict ways to improve the movement of cars in snow and ice, and explain why

Relate engineering with frictional forces, especially when designing automobiles

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

Click to view other curriculum aligned to this Performance Expectation

This lesson focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim. Science knowledge is based upon logical and conceptual connections between evidence and explanations.

The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. All positions of objects and the directions of forces and motions must be described in an arbitrarily chosen reference frame and arbitrarily chosen units of size. In order to share information with other people, these choices must also be shared.

Explanations of stability and change in natural or designed systems can be constructed by examining the changes over time and forces at different scales.

Suggest an alignment not listed above

Pre-Req Knowledge

Forces, Newton's laws of motion

Introduction/Motivation

Think about the last time you rode in a bus or a car. Why do the wheels on some cars spin out at a green light, while other cars go forward without spinning wheels? Why do cars come screeching to a stop when the driver slams on the brakes? What makes a car going 60 miles per hour stay on the highway traveling safely forward? The answer to all these questions is the force of FRICTION (and Newton's laws of motion, of course)! Engineers need to understand the force of friction so that they can design safe roads, tires, cars and brakes. Engineers also try to reduce the force of friction between moving mechanical parts so that they will last longer.

When a car's tires start to turn, the friction between the road and the tires make the car begin to move forward. Similarly, when a car is going around a corner, the friction between the road and the tires keeps the car from sliding off the side of the road (remember Newton's first law? Without the force of friction, the car would tend to go in a straight line - straight off the road!) When a car slows down, the friction between the road and the tires helps to bring the car to a stop as the wheels slow down. It is the friction between the wheels and the brake pads that causes the wheels to slow down. Obviously, friction is a very important force when you are riding in a car!

Imagine that there was a lot less friction between roads and tires. Pretend that there was the same amount of friction as there is between your shoe and ice if you walked across an ice-covered lake. What would happen? Cars would be slipping all over the road because the friction between the road and tire would not be sufficient enough to keep the tire "stuck" to the road. It would be hard for cars to start going because their wheels would spin. It would also be hard for the cars to stop. Imagine trying to stop a car by pushing on the brakes if there were no friction between the tires and the road - what would happen? Even if the wheels stopped turning, the car would keep sliding over the low-friction roads! The car would slide and spin out of control, going across the yellow line or into a ditch!

Sometimes, when it rains or snows, the friction between tires and the road can be greatly reduced, and there is the danger of the car sliding. Because of this hazard, engineers developed extra safe brakes - computer-controlled antilock braking systems (ABS). Because these ABS brakes are computer-controlled, they can sense what each wheel is doing at all times. Since the computer knows what all four wheels are doing, if one wheel is about to start skidding while trying to brake, the ABS system can adjust the other three wheels so that the car does not slide. Refer to the fun and hands-on associated activity Hovercraft Racers! for students to investigate the friction between two surfaces. Follow-up with the associated activity How Far? Measuring Friction Using Different Materials for students to explore how different textures provide varying amounts of friction to objects moving across them.

Our imaginary low-friction road isn't all bad news, though. If a car could get going with very little friction between the tires and the road, the car would be much more fuel-efficient because the engine wouldn't have to work very hard to keep the car moving. Transportation and automotive engineers make sure that roads and tires have the right amount of friction - too much, and the car engines would have to do more work to keep going; too little, and the cars would not stick to the road!

Engineers take advantage of this link between friction and tire/road dynamics to make roads with material that encourages friction for safety, but not too much friction, so that cars do not have to work too hard to move forward. In areas where there is a lot of snow, some people use special tires with metal studs because the metal studs poke into the snow and ice, creating more friction than rubber alone. Sometimes, roads are so icy that people even have to put chains on their tires to create enough friction between the car tires and the road so that they do not slip and slide all over the roads.

Following the lesson refer to the associated activity It Takes Two to Tangle to expand the idea of friction in personal relationships through stories.

Lesson Background and Concepts for Teachers

Friction is a force that arises when things rub together. The frictional force between the road and tire is what allows the tire to "push" off the road, thus moving the car forward (Newton's third law - the action is the pushing frictional force, the reaction is the forward movement of the car). Imagine a car being lowered on a jack. When the tires don't touch the ground at all (and so there is no friction between the tires and the ground), the tires can spin, but the car does not move. At the very moment that the tires first touch the ground, they "grab" the ground. That "grab" is the frictional force between the tire and the ground. When the tires "grab" the ground, the car moves forward. Sometimes, such as when a car is on ice, mud or sand, there is not enough frictional force for a car's tires to grab the ground, and so the car has a hard time moving forward (it spins out or slides). So, even though friction is often thought of as the force that opposes the motion of an object, the motion of a car would not be possible without friction! Friction may slow the car down as it moves along the road, but it also is the force that enables the car to move forward at all. It is the friction force that keeps the tires from sliding on the road. By the same token, it is friction that makes the car come to a stop when the brakes are applied. So, it is the force of friction that makes a car accelerate forward and also decelerate to a stop.

Friction is also very important when a car goes around a turn. If the friction between the road and tires is not sufficient, the car will slide sideways off the road instead of turning the corner. Dirt roads have less friction than paved roads, which is why cars sometimes slide around corners on dirt roads on TV or in movies. If cars are going very fast, the back tires can slide, making the car "fishtail" as it goes around the corner.

Associated Activities

Lesson Closure

Have the students explain what they think friction is. Why does it slow down movement, but at the same time make movement possible? Why is friction so important for engineers who build cars to understand? What are some additional applications of friction in day-to-day life and for engineers? What would life be like without friction?

Vocabulary/Definitions

Force: Something that acts from the outside to push or pull an object. For example, an adult pulling a child in a wagon exerts a force upon the wagon.

Friction: A force that arises when things rub together.

Newton's third law of motion: For every action there is an equal and opposite reaction.

Assessment

Pre-Lesson Assessment

Discussion Question: Solicit, integrate and summarize student responses.

What forces make a car going 60 miles per hour stay on the highway traveling safely forward? Why does the car not slow down, swerve right and left, or slide off the road? (Answer: FRICTION and Newton's third law of motion. The friction between the road and the car's tires make it travel in the forward direction.).

Post-Introduction Assessment

Question/Answer: Ask the students and discuss as a class:

Imagine trying to stop a car by pushing on the brakes if there were no friction between the wheels and the road. What would happen? (Answer: If there were no friction, the wheels would stop, but the car would keep sliding, and would not slow down at all. The car would only stop when it hit something.)

Can you think of a situation in which an engineer might want less friction? When might an engineer want more friction? (Possible answers: Engineers try to reduce friction between moving parts so that they do not wear down as quickly. Increasing friction is a useful way to slow things down - that is how the brakes work in a car, a bike or a scooter! There are many other possible answers to this question.)

Lesson Summary Assessment

Roundtable: Have the class form into teams of 3-5 students each. Have the students on each team make a list of ways that friction affects cars by each person taking turns writing down ideas. Students pass the list around the group until all ideas are exhausted. Have teams read aloud the answers and write them on the board. (Suggestion: Friction does not only occur between wheels and the road - it also occurs between all moving parts in the engine, the brakes, etc.)

Friction Boggle!: Repeat the same activity as above, except when the teams read aloud their answers and write them on the board, ask if any other teams came up with the same idea. If any other teams have the same answer on their sheet, all teams have to cross that answer out on their list. The team that ends up with the most "unique" ideas, wins!

Lesson Extension Activities

Ask the students go home and ride their bike, and return to school with some observations about the movement of the bike and friction that they've made while riding their bike. How are road bikes different than mountain bikes? Why are the tires different?

Ask the students to research hovercrafts. How do they work? How fast can they go? What kind of surfaces can they go over? What role does friction play in the movement of hovercrafts?

References

Gittewitt, Paul. Conceptual Physics. Menlo Park, CA: Addison-Wesley, 1992.

Hauser, Jill Frankel. Gizmos and Gadgets: Creating Science Contraptions that Work (and Knowing Why). Charlotte, VT: Williamson Publishing, 1999.

Kagan, Spencer. Cooperative Learning. Capistrano, CA: Kagan Cooperative Learning, 1994. (Source for Roundtable assessment.)

VanCleave, Janice. Physics for Every Kid: 101 Easy Experiments in Motion, Heat, Light, Machines and Sound. NewYork, NY: John Wiley and Sons Inc., 1991.

Wolfson, Richard and Jay M. Pasachoff. Physics: For Scientists and Engineers. Reading, MA: Addison-Wesley Longman Inc., 1999.

Copyright © 2004 by Regents of the University of Colorado.

Contributors Sabre Duren; Ben Heavner; Malinda Schaefer Zarske; Denise Carlson

Supporting Program Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: December 8, 2020

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Red Light, Green Light: Forces of Friction, Roads & Tires - Lesson

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Building upon their understanding of forces and Newton's laws of motion, students learn about the force of friction, specifically with respect to cars. They explore the friction between tires and the road to learn how it affects the movement of cars while driving.

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The gas escaping the CO2 Cartridge will push or accelerate the car forward.

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A good shape for your car is a sphere , this is a good shape because it is symmetrical which allows air flow over its surface and little disruption to the air stream.

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Make sure the tires aren't rubbing against your car and the lighter your car is the faster it will go. You could also help your car go faster by building more of a aerodynamic car but those are harder to make.

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The less mass your car has the faster it will go. You should probably make it so your car is lighter

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the way you can reduce friction is by making sure the axels are able to rotate and that the wheels are not to close to the car

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The less weight you put on your car the faster it will go, make the car thin a light weight

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The less weight you put on your car the faster it will go, make the car thin a light weight

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the less weight on your co2 car, the faster the car will go.

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the less weight on your co2 car, the faster the car will go.

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Introduction:

An important consideration in designing a vehicle is aerodynamics. Aerodynamics is the effect of airflow and the forces involved when an object moves through the air or when air moves past an object. Aerodynamics has taken on new importance since the need for more fuel-efficient vehicles. A poorly designed vehicle uses more fuel. The flow of air moving around a vehicle is called streamline. A body with an overall rounded or square shape will cause air to break away from the streamline into swirls of air. This uneven or turbulent air movement that will slow the vehicle down is called drag. Vehicles have less resistance if they are rounded in the front and tapered off to a point in the rear (teardrop shape). In this activity, you will design, construct, and test an aerodynamically sound vehicle. The car you will be building is like a miniature rocket powered dragster. As you build your dragster, take your time. It will have a better chance of looking good and going fast if you build it with patience and care. One major mistake can ruin the whole dragster and disqualify you from racing. Take pride in your work and try to make the best dragster in the class.

Problem:

You are an automotive design engineer in the research and development department of the ASA Automotive Company. You have been assigned the task of designing the new, fuel efficient, aerodynamically sound, stylish, and futuristic automobile for the company. You will be in charge of the designing, constructing, and testing of the new vehicle. All cars in the company will be compared for excellence in design, craftsmanship, aerodynamics, and the fastest racing time.

In order to keep the competition fair and for the safety of the entire class, there are certain specifications that must be followed by all students. Keep these specifications in mind when completing the design process for you CO2 dragster.

Research:

You will be given class time to use the Internet to search for information about CO2 dragsters. You must show documentation of your research, along with the web addresses used.

Materials/Supplies:

masking tape

sandpaper

soda straw

2 axles

4 washers

5/8" x 2-3/4" x 12" basswood block

2 rear wheels

2 front wheels

2 1/8" screw eyes

CO2 cartridges

Tools/Equipment:
Procedure:

1. Develop several thumbnail sketches. You should not just rely on one design at this point. Develop at least forty (40) different designs. Be creative. Don't be afraid to experiment with some far out designs. Thumbnails are little, not much detail, quick sketches to give you ideas.

2. Look over the thumbnails and choose the best three (3) ideas. Sketch these ideas a little larger, with more detail, and from several angles or views. These are your rough sketches.

3. Next you will complete one (1) Final Sketch of the car you think will be the best and the fastest.

4. Using AutoSketch, neatly draw your dragster exact size and detail using the 1/4" template located in the video folder. (Remember to the document to your DESKTOP when you first begin and the document often while you work.) This final drawing will be used as the pattern to cut out your dragster. Be sure to show the location of the axle holes.

5. Take your thumbnails, rough sketch, final sketch, and final drawing to the teacher to have them approved and graded.

6. Carefully cut out the top and side views of your car from your final drawing.

7. Tape the templates on your wooden block and trace around them with a pencil. Be sure to locate and mark the axle holes and engine housing. (Note: Tape the top view template to the bottom of the wooden block.

8. Drill the axle holes (3/16") on the drill press being very careful to keep them straight and parallel to each other. They should be 1/4" from the bottom of the car.

9. Cut the side view first using the band saw. Then, cut the top view, which you traced, on the bottom of the block. Be very careful not to cut into the engine housing.

10. Shape the body using a wood rasp, file, Dremel Tool, and sandpaper.

11. Finish smoothing the car using finer and finer grit sandpaper.

12. Take your car home and apply spray paint and/or decals (optional).

13. Cut two pieces of soda straw 1-5/8" long for bearings. Insert one straw through the front axle hole and the other through the rear axle hole.

14. Insert axles through the straws.

15. Place washers on each end of the axles.

16. Carefully place the wheels on the axles. Be careful not to break the wheels. If the wheel does not stay on place a drop of hot-melt glue in the wheel before placing it on the axle.

17. Install the screw eyes about 3/4" to 1-1/2" from each end of the body. They screw into the bottom of the car. Be sure that they are centered down the middle of the vehicle.

18. Take the completed CO2 car to your teacher for grading.

Evaluation:

1. The following are required:

Research (documentation of research, along with the address(s) used) = 20 pts

40 thumbnail sketches = 20 pts

3 rough sketches = 30 pts

1 Final Sketch = 30 pts

Final Drawing = 50 pts

2. LSRAV dragster = 100 pts

design (creativity/appearance) = 30 pts

workmanship (shaping/smoothing/finishing) = 50 pts

aerodynamic design = 20 pts

Total = 250 pts

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Introduction: An important consideration in designing a vehicle is aerodynamics. Aerodynamics is the effect of airflow and the forces involved when an object moves through the air or when air moves past an object. Aerodynamics has taken on new importance since the need for more fuel-efficient vehicles.

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Friction is when surfaces rub against each other, and this can slow down your car. To reduce it you should make sure your axles can move easily and your tires don't rub on the body of the car.

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My claim is that you should have a more light weight car so it can accelerate faster.

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You want to make sure that your car has equal weight in the front and in the back so it doesn't tilt or flip.

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A sphere shape is very good for a co2 car because it is symetrical and it allows the air to go over the surface with a small amount of distruption to the sir stream.

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Cars with a lot of flat, straight edges are faster because they're more aerodynamic. You should include a lot of flat edges in your design.

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved:

Mass: Obviously, this is how large and heavy the car is. Simply put, the less weight your dragster has, the faster it will go. This is the most important factor that will figure into your design. Keep it light!

Thrust: The gas escaping from the CO2 cartridge in the car. We'll cover this in a bit.

Friction: The second most important fact you'll face. Because the dragster has parts moving against one another, friction is created. You can help reduce it by making sure the axles are free to rotate, and that the wheels and tires are not rubbing on the car body.

Drag: Here's where aerodynamics come into play. As an object moves through the air, it is met with air resistance as speeds increase. This air resistance pushes against your CO2 car and prevents it from going as fast as it could in a vacuum. You can't completely ever reduce drag, but you can help reduce it by building a more aerodynamic car, but those are more difficult to create.

[source: Virginia Tech University Technology Education]

Of these three factors, drag is the toughest one to test for. It's hard to tell with the naked eye just how much drag your CO2 car will face. For that reason, you may want to opt for a wind tunnel. Believe it or not, there are small wind tunnels available designed to test models, like Pitsco's AirTech X-Stream Wind Tunnel [source: Science of Speed].

By putting your car into the wind tunnel and putting a fog vapor into the air stream, you can track how air flows over the car's body. You want a smooth flow of air free of swirling currents called eddies. If you have too many of those, you may want to use sandpaper to smooth out the design, or go with a new one altogether.

Up next, we'll examine what makes CO2 dragsters go: The power of carbon dioxide propulsion.

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Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved: Mass: Obviously, this is how large and heavy the car is.