Microwaves Shake Water
From the box to a water molecule
A microwave oven heats food without a flame. A wave 12 cm long bounces around the metal box, making hot and cold spots, then reaches into the food and shakes its water molecules. Follow it in 14 scenes, zooming in from the box to a single molecule.
Watch from the start in 3DChapter 1 · Where the Waves Come From
No flame, no hot plate — yet the food gets hot. What heats it?
- 1 How Does It Heat Without a Flame?
No flame and no hot plate, yet the food gets hot
View in 3D → - 2 Making Waves From Electricity
A magnetron turns electricity into waves
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Chapter 2 · Waves in the Box
How do the waves move inside the metal box?
- 3 Waves Trapped by Metal Walls
Metal walls bounce the waves and keep them inside
View in 3D → - 4 One Wave Is 12 cm Long
Each wave is about 12.2 cm long
View in 3D → - 5 Hot Spots and Cold Spots
Overlapping waves make hot and cold spots every 6.1 cm
View in 3D → - 6 So the Turntable Turns
Turning lifts the weakest spot from 31% to 71%
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Chapter 3 · When Waves Meet Food
What happens when the waves reach the food?
- 7 The Waves Twist Water Molecules
Plus and minus switch 4.9 billion times a second, twisting water molecules back and forth
View in 3D → - 8 Jiggling Becomes Heat
Twisted water molecules bump into each other and get hot
View in 3D → - 9 Only the Outer 1.6 cm
About 1.6 cm into food, the waves drop to about a third
View in 3D → - 10 The Middle Warms by Conduction
After 2 minutes: surface 50 °C, middle 34 °C — let it stand and it evens out
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Chapter 4 · So That’s Why
Now the everyday puzzles of a microwave oven make sense.
- 11 Why Is Ice So Slow to Melt?
Water molecules in ice can’t turn, so they barely absorb the waves
View in 3D → - 12 Why Don’t the Waves Leak Out the Door?
Holes much smaller than a 12 cm wave don’t let it out
View in 3D → - 13 Why Do Forks Spark?
Charge crowds onto sharp metal tips until the air sparks
View in 3D → - 14 Does It Make Food Radioactive?
One particle of microwave energy is about 500,000 times too weak to break a water molecule
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More in the series
Wavelength, standing waves and the properties of water are calculated with textbook formulas. The standing-wave pattern is a simplified sum of the metal box’s resonant modes; water’s properties come from the Debye model (water at 20 °C). In the 3D view, waves and molecules move far slower than in real life, and the water molecule is an enlarged model.