Quick QuizBefore we start
A small bet · What's your guess?

How many microwaves
are sold every second worldwide?

Option A
~ 0.5
one every 2 seconds
✓
Option B
~ 2
two every second
✓
Option C
~ 5
five every second
✓
Option D
~ 12
twelve every second
✓
→ Press to reveal the answer
Answer → Option B · ~2–3 per second — that's ~80 million a year
Make your guess — then we'll find out01 / 17
The Marvel of the Microwave2026
A talk in seven minutes

The Marvel
of the Microwave.

History · Science · Everyday Magic
1:30
By Florian Köppe & Gino Anaya Mendoza02 / 17
Table of ContentsAgenda
What to expect

The Menu.

  • 01 What is it? (Spectrum & Uses)
  • 02 The Accidental Invention (Percy Spencer)
  • 03 Inside the Box (Anatomy & Science)
  • 04 Mythbusting (Radiation, Nutrients, Metal)
A quick roadmap03 / 17
02 · The Question
Quick question
  • Almost everyone owns one
  • Almost no one knows how it works
  • Today — let's change that
?
Let's change that.04 / 17
03 · What is a Microwave?The Spectrum
Definition

It's a wave.

Microwaves
Radio1 km
Microwave1 m – 1 mm
Infrared700 nm
Visible400 nm
UV10 nm
X / γtiny
FREQUENCY
2.45 GHz
TYPE
Non-ionizing
SAFETY
Safe.
Between radio and infrared05 / 17
04 · Where you find themEverywhere
Same waves, four jobs
001
Wi-Fi
2.4 GHz · same band as your dinner
002
Radar
Ships, planes, weather
003
Mobile
Every call rides a microwave
004
Cooking
The accidental application
Same physics, different boxes06 / 17
05 · The Inventor1945
Percy Spencer
Percy Spencer · Raytheon
Meet the man
Percy
Spencer.
Engineer
Raytheon
Working on
Radar
Year
1945
Massachusetts, USA07 / 17
06 · The AccidentOne sticky pocket
The spark

A candy bar
in his pocket.

  • Standing near a magnetron
  • Chocolate melted in his pocket
  • Next test: popcorn popped
  • Then: an egg exploded
Watch it melt08 / 17
07 · The First Microwave"Radarange" · 1947
Two years later

The first one
was huge.

Height
1.8 m
Weight
340 kg
Price
$5k
1.8 m0
YOU · 1.75 m
RADARANGE · 1.8 m
It needed its own water cooling09 / 17
08 · Inside the BoxAnatomy
Four parts. One job.
2:00
1
2
3
4
01
Magnetron
Makes the waves.
02
Waveguide
Channels them in.
03
Turntable
Spins for evenness.
04
Faraday Cage
Keeps them inside.
Look at the door — see the holes?10 / 17
09 · The ScienceThe big idea
The mechanism is called

Dielectric
Heating.

  • Doesn't heat the air
  • Doesn't heat the plate
  • Heats the water — by spinning it
+ −
H₂O · spinning → heat
One word to remember11 / 17
10 · The MechanismWater = tiny dipoles
How it actually works

Water molecules
are tiny dipoles.

The microwave's electric field flips. The molecules try to keep up — and rub against each other. Friction = heat.
+ red, − blue. Ask me why.12 / 17
11 · The SpeedHow fast they spin
The molecules flip
5,000,000,000
times per second.
Five billion rotations every second. That's where the heat comes from — pure friction at the molecular scale.
2.45 GHz = 2.45 billion cycles/sec × 2 directions13 / 17
12 · Myth Number OneFact-check
MYTH 01
"Microwaves make
food radioactive."
FACT
  • Non-ionizing waves — no DNA damage
  • Vanish the moment the door opens
  • Like a lamp — off means off
Switch it off · light is gone
No glow, no leftover rays14 / 17
13 · Myth Number TwoFact-check
MYTH 02
"They destroy
all the nutrients."
FACT
  • All heat destroys vitamins — not just microwaves
  • Fast cooking · little water
  • Often more nutrients than boiling
Boiling
−55% vit. C
Microwave
−28% vit. C
Boiling broccoli is the real villain15 / 17
14 · Myth Number ThreeFact-check
MYTH 03
"You can never
put metal inside."
NUANCE
  • Sharp edges → sparks (forks, foil balls)
  • Smooth metal → reflects safely
  • The oven walls are metal!
  • When in doubt: leave it out
Sharp · forks
Edges concentrate charge — arcs fly.
Smooth · walls, mugs
Curves reflect waves — that's the oven itself.
Forks bad. Stainless mugs fine.16 / 17
15 · EndFin.
A wartime accident

That changed
dinner.

Thank you. Questions?
End of presentation17 / 17
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