Food Hot Plate vs Science Hot Plate

[mishima]

"Food" Hot Plate vs "Science" Hot Plate

I want to pick up a cheap hot plate for doing high school level demonstrations in chemistry. Is there any reason getting a normal hot plate would be a bad idea? Like this one?

Thanks.

 

[chemisttree]

From a customer review for the cheap hot plate on Amazon.

...the included thermostat only very roughly controls the temperature and allows it to fluctuate wildly.

That never happens with the http://sargentwelch.com/vwr-hotplate-stirrer/p/IG0037202/ I have used.

 

[mishima]

Will that matter much for high school level demos and experiments? Stuff like turning a penny into bronze by heating zinc sulfate, etc. Thanks.

 

[chemisttree]

Only you know the answer to that. Read some other reviews that describe it working for 2 weeks and then... KAPUT.

 

[mishima]

Well, I mean, how often do you really need a consistent heat source? What sort of things is it critical you don't have heat fluctuations? I'm coming from a lack of upper level chemistry experience/lab classes.

 

[Ygggdrasil]

One concern might be working with flammable solvents. Scientific hot plates will have been designed to not have any components that could potentially produce a spark to ignite flammable vapors. Food hot plates may not have been designed this way. See http://www.nap.edu/openbook.php?record_id=4911&page=116#p200063c99970116002

 

[chemisttree]

Exactly. Imagine you want to boil something flammable with this hotplate. You keep increasing the setting but it isn't boiling. You wait. And wait. Nothing is happening. You increase the setting a little further and WHAM. The hotplate goes into overdrive, overheating the solvent which boils with such force that the glass joints are blown apart and the apparatus falls to the floor. The boiling solvent fills the air with a cloud of flammable vapor, searching for a source of ignition.

Safety and control are priceless.