For classrooms

Each comic explains one piece of serious technology in four panels, then backs every number with sources. Here is every topic with a suggested grade band and two questions to start a discussion.

Every page prints cleanly on plain paper: the background grid, buttons and links drop out, and no panel splits across pages. Use the “Print this comic” button on any topic, or your browser’s print command.

1. GPS

   Grades 6 to 12. Or: how we used Einstein to find the DoorDash guy.

   1. Why does your phone need to hear four satellites, not just one?
   2. What is the dumb payoff, and what else do we actually use GPS for?

2. The power grid

   Grades 5 to 12. Or: splitting atoms to cool three beers.

   1. Why do power lines run at such high voltage before it gets to your house?
   2. What is the dumb payoff, and what in your home uses the most electricity?

3. Undersea cables

   Grades 4 to 12. Or: lasers on the ocean floor for dog videos.

   1. How does light carry a message through a glass fiber?
   2. What is the dumb payoff, and what else crosses the ocean through these cables?

4. Computer chips

   Grades 7 to 12. Or: wizard sand that mostly does email.

   1. Why does making smaller switches need such extreme light?
   2. What is the dumb payoff, and what would you rather use a chip for?

5. Weather forecasting

   Grades 4 to 10. Or: simulating the whole sky to pick a hoodie.

   1. Which three kinds of measurements go into a forecast?
   2. What is the dumb payoff, and when did a forecast actually matter to you?

6. Internet routing

   Grades 7 to 12. Or: a phone book run on trust, used to find pizza.

   1. Why does the internet work even though nobody is in charge of it?
   2. What is the dumb payoff, and what happens when networks trust a wrong route?

7. Bananas

   Grades 3 to 8. Or: a floating refrigerator for a snack you forget.

   1. Why are nearly all store bananas clones of each other, and why is that risky?
   2. What is the dumb payoff, and how far did your last banana travel?

8. The blue LED

   Grades 6 to 12. Or: a Nobel Prize for 3 a.m. scrolling.

   1. Why did white LED light have to wait for a blue LED?
   2. What is the dumb payoff, and where else do you see LEDs every day?

9. Barcodes

   Grades 3 to 8. Or: lasers that yell at you at self-checkout.

   1. How can a pattern of stripes stand for a number?
   2. What is the dumb payoff, and what does a store learn every time it scans one?

10. The microwave oven

    Grades 4 to 10. Or: wartime radar for lukewarm coffee.

    1. How does a microwave heat food without heating the air around it first?
    2. What is the dumb payoff, and what was the microwave's technology first built for?

11. Jet engines

    Grades 6 to 12. Or: metal grown like a gem to fly home for an argument.

    1. How can a blade survive gas that is hotter than its own melting point?
    2. What is the dumb payoff, and what else do jet engines make possible?

12. Card payments

    Grades 6 to 12. Or: a global fraud-sniffing network for one latte.

    1. Why does a tap make a new one-time code instead of sending your card number?
    2. What is the dumb payoff, and how many steps happen before the terminal beeps?

13. Lithium-ion batteries

    Grades 6 to 12. Or: a Nobel Prize that still dies at 14%.

    1. Why was the first lithium battery too dangerous to sell?
    2. What is the dumb payoff, and why does an old phone die before it reaches zero?

14. Smoke detectors

    Grades 5 to 12. Or: nuclear leftovers that yell at toast.

    1. How does a speck of americium make an electric current, and what does smoke do to it?
    2. What is the dumb payoff, and what should you check when you change the battery?

15. Wi-Fi

    Grades 6 to 12. Or: black hole math for bathroom cat videos.

    1. Why do radio signals indoors arrive as a smear of echoes?
    2. What is the dumb payoff, and what did the astronomers actually go looking for?

16. Phone motion sensors

    Grades 6 to 12. Or: a silicon gyroscope that hates when you lie down.

    1. How can a vibrating piece of silicon tell that your phone is turning?
    2. What is the dumb payoff, and where else are these sensors hiding?

17. Noise-cancelling headphones

    Grades 5 to 12. Or: anti-sound for ignoring your roommate.

    1. What happens when you add a sound wave to its upside-down copy?
    2. What is the dumb payoff, and why do voices still get through?

18. Phone cameras

    Grades 6 to 12. Or: a Nobel-winning eye for photographing lunch.

    1. How does a chip turn light into electric charge it can count?
    2. What is the dumb payoff, and why would a phone take many photos for one picture?

19. CAPTCHAs

    Grades 5 to 12. Or: proving you’re human to robots who do it better.

    1. How did typing squiggly words help digitize old books?
    2. What is the dumb payoff, and why are CAPTCHAs getting harder to use?

20. Inkjet printers

    Grades 5 to 12. Or: tiny ink explosions that refuse to print black.

    1. How does boiling a tiny bit of ink push a drop onto the paper?
    2. What is the dumb payoff, and why is printer ink so expensive?

21. Toilets and water treatment

    Grades 4 to 12. Or: a city-sized chemistry plant for your poop.

    1. What are the four steps that turn river water into drinking water?
    2. What is the dumb payoff, and how much water does your home flush in a day?

22. Song recognition

    Grades 6 to 12. Or: a star map of sound for the grocery store song.

    1. How can a few seconds of noisy sound become a fingerprint?
    2. What is the dumb payoff, and why does matching work even with people talking?

23. Air conditioning

    Grades 4 to 12. Or: a printing press fix for hoodies in July.

    1. What problem was the first air conditioner actually built to fix?
    2. What is the dumb payoff, and why does cooling use so much electricity?