On 22/02/2019 19:41, Max Demian wrote:
On 22/02/2019 13:01, NY wrote:
"Max Demian" wrote in message
o.uk...

Do they still use gas marks rather than degrees Celsius in gas ovens?
I haven't seen an explanation why gas ovens use these arbitrary
numbers rather than degrees (Fahrenheit or Celsius), though I have
some ideas why it might have happened.

Yes I've never understood why gas ovens historically used arbitrary
"gas marks".

My *guess* is that gas ovens were the first to have thermostats, as it
is easy to regulate gas flow with a tap, whereas the thermostats in
electric ovens work by switching the power on and off - hard to do
without sparking the contacts with the switches at that time. (I'm
thinking of the 1930s here.) I imagine electric ovens would have had a
high/medium/low switch and a thermometer in the door like the later Baby
Belling table top cookers.


More likely because houses had gas and not much electricity so they
could have a gas cooker but an electric one wouldn't have any power.


Perhaps the makers of the first thermostatic gas ovens lacked confidence
in their accuracy; or it was thought that degrees Fahrenheit would
confuse housewives and simple numbers would be easier for them. In any
case, they screwed up as presumably the original scale went from 1 (275
°F) to 9 (475 °F) and they realised that they needed an extra two marks
for lower temperatures: ½ (250 °F) and ¼ (225 °F).

This is all guesswork, however.




The scale of course was to make it simple rather than having degrees F
and now C as well.