Text LOL (Nate Fulmer)

Title: Text LOL

Principle(s) Investigated: Linear motion, d = vt, unit conversion

Standards : NGSS

Materials: Student cell phones, spread sheet app

Procedure: Students are divided into small groups of ~3. One member is the driver, the others will act as time keeper and recorded taker. The driver is told they are driving along the freeway at 65 mph when they feel the familiar buzz in their pocket. As quickly as possible, the driver must reach into their pocket, unlock their phone, and text “LOL” to a friend. The other group members will run the stop watch to see how long it takes them to send the text. As a group, the class will use the given speed and the time recorded to calculate the distance they would have traveled in that time.

Student prior knowledge: Student will already need a handle on the relationship between distance, velocity, and time.

Explanation: Make sure every student gets the chance to be the "driver." Different students have different cell phones with different modes of unlocking and texting, and that's fine. Collect all student data from across the class and aggregate it into a single, class-wide histogram or bell curve. Students can then see where they are in context of the rest of the class. Use the average time across the class as an example. Since the time is in seconds and the speed in miles per hour, this will be a good place to discuss unit conversion -- feet per second will probably make the most sense. Use d = vt to solve for the the distance traveled. At 65 mph, typical distances are usually around 1/5 mile, which surprises a lot of students. This thought experiment helps give scientific validation to the dangers of texting and driving and hopefully allows the opportunity for students to view a commonplace activity through the eyes of a scrutinizing scientist -- evaluate texting while driving scientifically, empirically, and critically.

Questions & Answers:

1. If the car were traveling at 30 mph, how far would it travel in feet?

~260 - 570 ft

2. How far in would light in a vacuum travel in this time?

~5.9e9 - 1.3e10 ft or ~1.1e6 - 2.5e6 miles

3. How far in feet would a jet plane (600 mph) travel in this time?

~5300 - 11,400 ft or ~1 - 2.2 miles

Applications to Everyday Life: This principle applies to any circumstance where either the velocity of an object is constant or you're interested in analyzing average velocity. E.g. if your mile time was 8 minutes, your average velocity was 7.5 mph; if it's 10 miles between your work and home and it takes you about 30 minutes to get between them, then your average velocity is 20 mph (great place to talk about the difference between average and instantaneous velocities); since the distance between the pitcher's mound and home plate is 60.5 feet, a 90 mph fast ball will take 0.46 seconds to reach the batter.