Naked Science Forum

Non Life Sciences => Technology => Topic started by: Chemistry4me on 14/06/2009 04:48:54

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: Chemistry4me on 14/06/2009 04:48:54

Is there any reason for me to believe that if I place my 2 minute noodles right on the edge of the spinning plate it'll cook slower?

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: Chemistry4me on 15/06/2009 03:44:32

Is that a 'no' then?

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: lyner on 15/06/2009 07:56:27

I think that, if you put the food right at the edge, it may well not be in the highest regions of Electric field strength so it may cook slower. The Electric field drops to zero at the wall, which is a 'short circuit'. But the currents in the wall may be higher so I'm not sure what effect this would have on the molecules of water in the food - not much, I suspect.

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: Don_1 on 15/06/2009 08:25:57

I have conducted a quick experiment for you, to accentain the properties of our microwave oven.

Equipment

One Philips Whirlpool Jet Microwave oven
Two BHS mugs
One probe thermometer
Water

Method

Two identical mugs were filled with 100ml of water. The temperature of the water was noted at 17.5^oC.

One mug was placed at the center of the turntable, the other at the edge of the turntable. The microwave oven was set to 750 watts and 90 secs.

The experiment was repeated with fresh water for a period of 120 secs.

The experiment was then altered to microwave one mug only at the center of the oven, then one mug only at the edge, each for a period of 60 secs.

Results

Exp. #  - Centrally placed mug - Edge placed mug

1   -           31.6^ooC                     33.5^ooC
2   -           38.4^ooC                     40.9^ooC
3   -           35.2^ooC                     35.2^ooC

Evaluation

It appears that there is no difference when placing an item at the center or edge when microwaving a single item, but when microwaving multiple items, those on the edge will heat faster than those at the center.

Finale

I now have several hundred mls of luke warm water which I shall tip into the kettle to make a cup of coffee.

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: Chemistry4me on 15/06/2009 09:24:30

Wow, thanks matey!

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: Don_1 on 15/06/2009 10:00:50

Later today I shall conduct similar experiments with a box of 50 Bird's Eye^® frozen 'ding' meals. Being the type who detests waste, I shall, of course, consume said 'ding' meals once thoroghly heated, according to the manufacturer's instructions.

Should I become as fat as a pig, or fatter than the pig I am already as fat as, I shall blame you!

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: Chemistry4me on 15/06/2009 10:27:42

Sharing is caring. You should share then.

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: lyner on 15/06/2009 14:33:26

If you have a turntable then your food is kept from the edge. Also, a liquid will convect and reduce the localised power distribution.
A good test would be to put some cake mixture (neoprene bakeware) right next to the wall and see how uniform the cooking is. Take out the turntable and use a square baking vessel.

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: BenV on 15/06/2009 14:48:07

I guess it will depend on the distribution of hotspots in your oven, and the size of the food.  Should there be a hotspot right in the centre, then a small meal will cook quicker as it's constantly in a hotspot - a large plateful will overcook in the centre and undercook elsewhere.

However, if a hotspot does not coincide with the centre, then moving through hotspots will be better than sat next to one.

Test it out, and measure the speed of light at the same time - http://www.thenakedscientists.com/HTML/kitchen-science/exp/measuring-the-speed-of-light/

Title: Does my food cook faster in the microwave if it is placed in the middle?
Post by: lyner on 17/06/2009 14:19:38

I have always thought that was a bit of a cheat method - you are relying on someone else having measured the frequency of your microwaves first.
But all's fair in love and Science.