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Microwave madness

Microwave madness

By Paul Armstrong and John Chambers
Microwave Array and Technology Centre, Cambridge, UK.


The success of the microwave has been told in numerous accounts in the literature and on the Internet. Invented by Percy Spencer in 1945 as the magnetron, it has evolved considerably in power, size and shape and is now found in kitchens all around the world.

Radio waves can be fun - millions of amateur CB radio enthusiasts use them all the time to tap into conversations and communicate with other like-minded geeks; kids all around the world use them to manipulate radio-controlled cars, boats and ‘planes; many of us tune into our favourite radio stations to listen to music, news, plays and sports coverage; most of us have mobile ‘phones which also use radio waves for communication. However, many of us do not think of microwaves as being in the same bracket.

Microwaves are pretty neat inventions then, they work using radio waves (usually in the 2500 frequency range), which are absorbed by water, fats and sugars. This converts into heat and excites the molecules in the food. As the food is heated from all angles at the same time, it cooks evenly throughout. Perfect.

But, just what is safe and what is not safe to cook, play with and provoke in a microwave? Here we provide a list of common items that have been tried and tested in the microwave under laboratory conditions. Please do not try this at home; we are experts in the field of microwave array technology.


We took a number of everyday items and subjected them to controlled microwave bursts in a standard 900-Watt output microwave oven. Observations were made during the time the door was closed and the oven turned on, although these were occasionally hampered by steam and flying debris. Total microwave time - TMT - is noted for each item.

Results (in no particular order)

Looked like it may start sparking but just sat there doing nothing. Well-rounded spoons apparently do rearrange the microwaves slightly, but they do not spark nor overheat. Forks, however, do spark lots.
TMT: 2 minutes, experiment aborted.
Eggs going bang!
Eggs (raw)
Looked innocent enough until after 45 seconds it exploded with a cataclysmic splat, coating the door, roof and sides of the microwave in scrambled egg (see picture).
TMT: 45 seconds.

Glue stick
Melted, remained sticky, and still able to glue most things - just very hot glue.
TMT: 1 minute 30 seconds, experiment stopped.

Keys melt, LCD screen bubbles after 2 minutes, Goes black after 2m30s, catches fire after 3m25s.
TMT: 3 minutes 27 seconds, experiment aborted, fire extinguished.

Potato (King Edward's)
No outward changes of appearance up until 28 minutes. Some potatoey odour. After 36 minutes, started to go wrinkly, after 48 minutes black, after 64 minutes, black, hard and excessive smoke.
TMT: 64 minute, experiment aborted.

Ballpoint pen
Ink reached boiling point in just under 1 minute. Ink flowed everywhere; pen was red hot and failed to write anything.
TMT: 57 seconds, pen discarded.
Sparks fly!
Fountain pen
Sparks flying from nib after 15 seconds, ink reached boiling point in just under 1 minute. Ink cartridge exploded after 75 seconds, pen failed to write anything.
TMT: 75 seconds, NB: Ink is a nightmare to get off a microwave wall.

Pasta (uncooked)
Nothing, just hot dry pasta.
TMT: 1 minute, experiment aborted.

Sun-dried raisins
Lost their plumpness after 2 minutes, after 3m20s began to go black and started smoking.
TMT: 3 minutes 25 seconds, experiment aborted, raisin removed and doused in water.

Silicon implant
Implant started shrinking after 1m 13 seconds, exploded after 2m 27 seconds. Do not stand in a microwave if you have silicone implants.
TMT: 2 minutes 27 seconds, experiment aborted, silicone removal experts called in.

Light bulb (60w)
Bulb begins to light up after a few seconds. Under 50% power, the bulb begins to pulse, but that’s all it does.
TMT: 12 minutes, experiment aborted due to author boredom.

Milk (in a carton)
Milk boiled after 74 seconds. Carton exploded after 98 seconds. A pint of milk makes a hell of a mess in a small microwave.
TMT: 1 minute 38 seconds, experiment aborted, flood ensued.

Aluminium foil
Thin strip of tin foil in the centre of the oven created blue sparks and much burning and crackling as UV light is given off.
TMT: 20 seconds, experiment aborted for fear of UV skin damage.

A sock
Nothing, although authors can confirm it smelled better upon removal.
TMT: 18 minutes.

A grape was cut lengthways and placed in the microwave with centre facing upwards. A fantastic plasma show ensued, with pulses of ball lightning type plasma flowing from the grape.
TMT: 26 seconds, show stopped.
A CD - sadly not playable after the event. c/o Stefan Wieman
As the microwaves make their way through the outer plastic coating to the metal surface, they flicker and blue sparks were observed over the disc surface (see picture).
TMT: 3 minutes 20 seconds, experiment aborted after sparks ended.

Cigarettes (whole, filtered)
Looked darker in colour after 2 minutes, but little outward change of appearance. Too hot to smoke upon removal.
TMT: 2 minutes 34 seconds, experiment aborted, tar stains scrubbed off microwave.

Stamp (first class)
After 35 seconds the underneath surface started bubbling. Lost its stickiness after being allowed to cool.
TMT: 35 seconds.

Jelly baby
Looks like something out of a horror film, as the body begins to bubble, melt and deform until it spills its contents onto the plate.
TMT: 4 minutes 38 seconds, experiment aborted after jelly baby death.

Dry ice
Amazing! It just disappeared...
TMT: 3 minutes 46 seconds, experiment stopped, magic circle contacted.

£20 note (sterling)
Metal strip caught fire after 1 minute 28 seconds.
TMT: 1 minute 28 seconds, experiment aborted, note sadly ruined, damn.
Soap: frothy c/o Stefan Wieman
Soap (bar of)
Wow, this one is great! It grows to about five times its original size after a matter or minutes and lathers up like there is no tomorrow (see left).
TMT: 5 minutes, experiment aborted due to oven being entirely filled with soap! Very clean oven though.

m&m (peanut variety)
Begins to spark, then catches fire. Lovely nutty chocolate smell.
TMT: 3 minutes.

A brick
TMT: 128 minutes, experiment aborted.

Not recommended.
TMT: 3 minutes 7 seconds, experiment aborted, chemical experts called in, kitchen area sealed off.

Nothing much happened, although probably not very good for the cactus.
TMT: 7 minutes 14 seconds, experiment aborted due to botanical concerns.

Lit candle
Similar to the grape, a plasma fireball appears from the top near the flame. Lit up the entire microwave and caused charring of the oven roof.
TMT: 3 minutes, experiment aborted due to intense flames and concerns for our safety.

The physics underlying why metallic and grape-ic substances react the way they do in response to microwaves is undoubtedly fascinating, but it is still physics so we’ve decided to think about it later.

Putting everyday objects in microwaves for entertainment is a silly, puerile and frankly dangerous pastime, which is what makes it such good fun. We don’t take any responsibility if you’re daft enough to try and repeat any of the above, and if you end up setting fire to your microwave/ hair/house please don’t contact us, the fire brigade will be much more use.

Mssrs Armstrong and Chambers will return once they’ve had time to sit down and think about what they’ve done. You never know, they might even have some explanations for their results.

Thanks to Stefan Wieman for the CD and soap pictures, see more of his mad microwave experiments online, including photocopier lamps, blown bulbs and Christmas tree ornaments at


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16 Jun 2010
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