#### Transcript Unit 2 Power Point

```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:
the Compressed Air Car
Design project.
-Evaluate how drag and
weight can affect a car’s
aerodynamics.
Glossary
Aerodynamics-As a car drives down a road, air flows around it.
The way air flows around cars and other objects is studied in
aerodynamics. Engineers use what they learn in aerodynamics to
design fast cars, boats, airplanes, and even rockets.
Drag-As a car drives down a road, the air flowing around it resists
its motion and slows it down. The force that slows down the car is
called drag. A race car engineer’s goal is to minimize drag so a car
can move as fast as possible.
Glossary Continued..
Form Drag- Recall that drag is a force that slows a car down. When drag is caused by the
shape of the car, it is called form drag. Designers try to minimize form drag by
streamlining a car body. Streamlining is shaping a car so that it has the smallest amount
of drag when air flows around it.
Transition Point- When air flows over a car, it follows the shape of the car. If the smooth
air flow is interrupted, it moves away from the car and flows in many different directions.
It swirls and twist in little pockets of air, called eddies. This air flow is turbulent. The
location where the smooth air becomes turbulent is called a transition point.
Eddies
This car body is level and even. Because the transition point is at
the rear of the car body, the air flow is streamlined over most of
the car body.
Race Time-23.12 seconds
This car body is blunt. Because the transition point is at the middle
of the car body, the air flow is streamlined over only about half of
the car body and turbulent over the other half of the car body.
Race Time -24.28 seconds
This car body is rough and choppy. Because the transition point
is at the front of the car, the air flow is turbulent over most of the
car body.
Race Time - 26.95 seconds
Aerodynamics studies the way air flows around objects.
Drag is a force that slows a car down. Form drag is drag
produced by the shape of the car.
Streamlining is shaping an object so that it has the smallest
amount of form drag as air flows around it.
A transition point is a location where smooth air becomes
turbulent.
The ideal car body has a transition point as far back on the car as
possible.
Glossary
Aerodynamics- Recall, aerodynamics is the study of the way air
flows around objects. Engineers use aerodynamics to develop
fast cars.
Weight- The weight of a race car can affect how fast it moves.
Weight is a measure of the force of gravity on an object. It is a
measure of how heavy an object is. The car’s weight is a result
of the materials that are used to build a car and the way those
materials are used. Often specifications establish the minimum
and maximum car weight allowed for competition.
This car has a standard body design and is made from light
materials. Because none of the car’s center section has
been hollowed out, it is heavier than the red and blue cars.
Race Time – 25.31 seconds
This car has a standard body design and is made from light
materials. Because some of the car’s center section has been
hollowed out, it is lighter than the yellow car, but heavier
than the red car.
Race Time – 22.60 seconds
This car has a standard body design and is made from light materials.
Because most of the car’s center section has been hollowed out, it is
lighter than the blue and yellow cars. But when this car races, it does
not offer enough support to the wheels and axles. The axle will
break through the wood, and the car cannot finish the race.
Top View
Race Time – N/A
Weight is a measure of how heavy an object is. The weight of a
race car can affect how fast it moves.
The ideal car weight is one that is as light as possible, but does
not sacrifice its strength.
Congratulations! You have completed Unit 2- Gather
Information. You will now move onto Unit 3.
The power point is titled “Unit 3 – Develop Solutions”.
```