THE AIR CAR
Grades 9-11

Students will engage in a physical science investigation into velocity and acceleration by building an air car and testing acceleration rates.

EUREKA: #5 Acceleration II: Calculating Acceleration and #4 Acceleration I: Force=Mass x Acceleration (optional)

FUTURES WITH JAIME ESCALANTE: #4 Automotive Design

Students will be able to:

• determine the velocity of a vehicle
• demonstrate how velocity, force, mass and friction are inter-related
• define and calculate acceleration

(One set for each group of 3 students)

• one standard paper clip
• three "jumbo" paper clips
• two plastic straws
• two large index cards
• narrow masking tape
• rubber bands
• bond paper cut to fit pencil length -35.6cm x 21.6cm approx.
• "Building an Air Car" handout for each student
• "The Air Car" student questionnaire

Tools

• pencil
• drawing compass (if circles not pre-drawn)
• pliers (needle nose)
• scissors
• stop watch, meter stick

Constructing an Air Car - Allow one full class period for assembly. This activity works well when students work in groups of three to create one air car.
Explain to the students that they will construct and test air cars as part of an extended investigation into automotive design, velocity and acceleration. Once their cars are completed, they will calculate and run time trials and then make design modifications.
Divide students into groups of three and instruct one person from each group to pick up the materials and tools that will be needed for the activity. Refer to the "Constructing an Air Car" directions and diagram.
When students have constructed their cars and have checked that their cars accelerate, proceed to the first viewing activity.

Explain to students that they will determine the performance capabilities of their cars. Lead students to discuss speed (distance per time, such as miles per hour) and change in speed, or acceleration, as two major performance specifications measured on vehicles.
Introduce the short video as overview of the basic information they will need to understand to conduct their time trials.

Eureka is a series of five minute animated videos which cover physical science principles in a brief and humorous manner. Each program in a module builds on the previous program. The information is delivered rapidly. BEGIN with #4 "Acceleration I" if you think your students need this basic knowledge first.
CUE Eureka #5, "Acceleration II" to the beginning of the program. Each program begins with a summary of the previous program or programs in a specific module. FAST FORWARD through the review of program #4 if appropriate.
Review the main focus viewing questions (questions #1 -5 on the handout) with students but don't pass out the handout.



Focus Viewing Questions:

1. How would you define "acceleration?" (Rate of change in speed per time period.)

2. If we measure speed in terms of hours, why do we usually measure acceleration in terms of seconds?
(Because acceleration usually occurs in seconds rather than minutes or hours.)

3. How do you determine the speed of a vehicle? (Distance divided by time.)

4. One meter per second per second is also written as _________? (1 m/sec x sec)

5. How do you determine the acceleration of a vehicle? (The video does not give the formula from this, but rather explains what acceleration is. You will have to lead the discussion afterwards to explain that acceleration is determined by dividing the change in speed divided by the change in time.)

First viewing: Show the program from beginning to end without interruptions. Students will respond to the humor and watch for visual and auditory cues which address some of the focus questions. STOP tape at the end of the program.
Discuss with students how they might determine the speed of their car. (Marking off a 4 meter long flat track at one meter intervals, and timing how long it takes for the car to travel a measured distance.)
Also discuss the fact that the car is NOT traveling at a constant speed, but rather increasing and decreasing in speed in a given period of time. Tell them this is the basis for acceleration.
Second viewing: Pass out "The Air Car" student handout and rewind the video to the beginning using your remote control. You will use the second viewing technique which works well with this short 5 minute program. Give students a few minutes to review the questions and write in any answers they recall from the first showing of the video and the discussion.
The second viewing allows students to complete the handout and verify their understanding of the discussion. Before showing the video a second time, tell students to instruct you to pause when key points from the handout are addressed. REWIND portions if necessary. Students will be able to complete most of the handout during the second viewing.
Ask students how one determines the speed of a vehicle. In particular, how could they determine the speed of their cars?
CUE Futures with Jaime Escalante: #4, Automotive Design.
PLAY the video from the beginning for about one minute. Jaime discusses on a chalkboard, how velocity is determined. Right after he does that, stop the tape. Ask students to clarify how velocity is determined. Explain that they are going to use distance and time to figure out the speed of their own cars.
Return to the student handouts. Allow students time to complete their data table and questions #6 and #7.
Press PLAY to RESUME the video as Jaime and his guests discuss car design. After the program, invite students to list any new ideas for modifications under question #8 on their handout.

With masking tape, mark off a four meter race track in 1 meter increments and perform timings. It will take three people per timing. The first person gets the car ready (turns the propeller). The second person times how long it takes to get to the one meter mark, and the third person times how long it takes the car to get to the 2 meter mark. Students take time trials, calculating the velocity and acceleration of their cars. They record their data in the Activity Data Table on the handout. To further investigate acceleration, you may want to
calculate the acceleration in the first meter, second meter, and so on, and compare the figures and discuss why they are different. Provide floor space to see how far (distance) their cars can travel. They should record this data.
Allow students to alter their cars (add rubber bands, modify supports, etc.) to increase the velocity of their cars. Take addition time trials to see if their modifications improve the performance of their cars. Students should list any modifications they made or plan to make on the handout, #8. However, tell them they may want to add or subtract information after the next viewing activity.

Log on to the Consumer Reports web page and investigate their evaluation of various model cars based on the performance specifications. Make comparisons between different makes. Challenge students to find out why some body types have different acceleration rates than others (van vs a 2-seater, for example.)
Automobile Related Sites
http://www.cyberauto.com
http://www.consumerworld.org
http://www.autosite.com
http://www.kars.com/mototrend
http://www.toyota.com
http://www.laguna-seca.com
http://www.galaxy.einet.net/galaxy

1. Discuss the significance of friction in acceleration: Where does friction occur? How could friction be reduced? Challenge students to modify their cars with other materials not supplied by you to increase force (a different propeller) and/or reduce friction (washers placed significantly.)

2. Log on to the Internet and search for various motor vehicle companies, such as Ford, GM and Honda. Investigate different car models and specifications and determine their acceleration rates.

3. At each car company's web site, investigate "what's new" in technology to improve performance specifications in terms of body and mechanical engineering.

Master Teachers: Randall Lam and Stan Hitomi