Curved+Mirror+Design

This project is currently just theoretical because I haven't determined if two pieces of flat mirror will simulate a curved mirror. I think they will, but I would have to get some mirrors and give it a try.

Kick Off Have students experience the need for an optimal field of view to be designed into the mirrors used on automobiles.

Have one person form each team use a mirror to back a foot driven cart. The car would consist of wheels mounted under a 4 by 2.5 foot frame. Two of the wheels could be of the caster type and I would limit how far they could turn. Have a seat at the rear end of the frame. Put a box over the frame that has a side mirror mounted, like one on a car, outside of a small window. (Use a really tiny flat, convex, or concave mirror.) Have students sit on the seat and move the box around a course backwards using the mirror. One student from each team. (Alternative: Put a small hole for a front window and have students parallel park.)

Read these and see how this problem applies to the real world. [] []

The Challenge Determine the best filed of view size for a car mirror to make backing up more successful while reducing a car's left side blind spot? (The field of view on a submarine periscope could also be optimized.)

Mapping the Lesson to the EDP

Problem/Goal: Side mirrors on cars are small and have a small field of view. Curved mirrors can provide a larger field of view, but distort the view. Determine the curve of a 10 cm wide mirror that will work well for both backing and observing a car's blind spot. Work in teams to simulate this curved mirror with two flat mirrors. Then determine the optimum field of view for backing while still reducing a car's left side blind spot. Support your answer with findings and a range for the optimum field of view for a 10 cm wide mirror.

Research Investigate the mirrors used in automobiles. Investigate mirrors and the law of reflection using the internet and the activity at this link. Investigate the field of view in curved mirrors. http://physicalsciencecottrell.wikispaces.com/Law+of+Reflection+Lab

Develop Figure out how to use two flat mirrors like a curved mirror and test the changes in the field of view. (If a flexible mirror is available use it.) Make a graph of different angles between the two mirrors and the corresponding fields of view. Write ratios for the mirror width and the fields of view widths in a table. Use the distance to the back of the card board box car for determining the field of view. (Any math teachers have a better idea on how to apply math to this problem?)

Choose Decide on the angle between two mirrors that will simulate a curved mirror that would work well for both backing and observing a blind spot.

Create Construct a prototype using two mirrors that will attach to the box car used in this activity.

Test and Evaluate Have all the teams do timed runs of the course or parallel parking.

COMMUNICATE Discuss the results of the test with other team members.

Redesign Redesign your mirror for another time trial.

COMMUNICATE Make recommendations for a follow-up redesign and produce a report

Teacher information: Activity cost: Mirrors, tape, string, popsicle sticks, cardboard, small nails, wood, caster wheels, big card board boxes. Two 5 cm by 5cm mirrors per team. Or a 5 cm by 10 cm or 15 cm thin, flexible, acrylic, mirror if you can find one.

Possible mirror sources: http://www.flinnsci.com/store/Scripts/prodView.asp?idproduct=15668 This material might flex enough to produce a curve. https://www.interstateplastics.com/Acrylic-Mirror-Clear-Extruded-Mirror-Sheet-ACRCLEE.php?

Source for the "anatomy" of this activity: http://www.middleweb.com/7048/anatomy-of-a-stem-lesson/