# Fifth Period

## First Time Here?

Go to the first strip and
see how it all started!

Join students Sophie, Tomás, Emma, and Marcus during Fifth Period! This STEM comic strip chronicles the exciting and often hilarious adventures of a close-knit group of four friends as they learn about science, technology, engineering, and math from their kooky, inspiring, off-the-wall science teacher, Mr. Kepler. When they're not in class, these kids love to explore the vast world of STEM on their own, launching weather balloons, programming computer games, and cataloging insects, sometimes with unpredictable and highly entertaining results!

Check back on the first and third Friday of every month for a new Fifth Period strip!

September 6, 2013

### Mr. Kepler Strikes Again

It’s true! Sound travels slower than light. We see light almost instantaneously because light travels so fast (186,282 miles per second!). But sound is actual oscillations (movement to and fro) of a fluid, like air, so it takes longer to get to us. Marcus actually knows that the speed of sound is 1,126 feet per second and that a mile has 5,128 feet. But since he is a master estimator and knows what to do to make quick calculations, he rounds both those numbers down to 1,000 feet per second and 5,000 feet. No storm will ever surprise him! Mr. Kepler’s “shocking” prank on the other hand...

Try it yourself!

Next time a thunderstorm rolls in, count the seconds between the lightning flash and thunder. Just remember, if you can hear thunder, a lightning strike is close enough to hit you, so stay inside!

Also, if you are lucky enough to visit a quiet canyon or someplace like that, try shouting across it. Time how long it takes to hear your echo with a stopwatch—if you multiply the number of seconds by the speed of sound (1,126 feet/second), you can get an approximate distance to the other side! But wait—the echo you hear has had to travel out and then travel back—twice as far. So you have to take the time times the speed of sound, and then divide that by two to get the distance to the other side. A similar thing happens with radar, but that’s a problem for another week!