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!
Sour Power
Let's put aside for a moment that Tomás should have a power adapter at the ready to recharge Robodog. The big question is, why on earth did Emma wire the gang’s faithful mechanical canine to a bunch of lemons?! Well, lemons are full of citric acid (that's what makes them so sour!), and an acid can actually be used to generate electricity.
Try it yourself!
You can make a lemon battery using a couple of juicy lemons, a few household items, and some common electrical tools (that your parents may have or that may be available in your school’s science lab). Your lemon battery won’t have enough voltage to power a robot dog, but it can be used to power an LED light!
Each lemon can be thought as a little hill, providing enough incline (or potential) to move a little ball a short distance. The little ball is like your electrical current. If you put a lot of hills together in series (one right after the other), all of these hills can work together to roll a ball a long way. Each lemon battery provides a little bit of electricity—or more correctly, electrical potential. When combined in series, that potential is enough to power a low-light LED for a time.
There are other ways to wire your lemon battery, but that’s a discussion for another day. For now, enjoy the lemonade!