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Testing Leaves For Starch

Posted: 01 Apr 2016, 08:08
by Whspa
My HT is saying that this prac, which involves test tubes of hot metho, has been banned.
She says that it's because of occasions where the metho has been heated over a Bunsen and the fumes have ignited.
Has anyone else heard this?
We use hot plates to heat a beaker of water to boiling, then put the test tube of metho and leaf into the hot water.

Re: Testing Leaves For Starch

Posted: 01 Apr 2016, 08:27
by Whspa
I can answer my own question. The DEC did issue Safety Alert No 50 which states that
"Schools must ensure that methylated spirits is not heated directly over a Bunsen burner even in a closed container such as a flask with reflux condenser. The recommended method is the use of a water bath whereby the flask is less likely to crack. Any failure of the flask using this method would substantially dilute the methylated spirits and minimise any potential for injury."
So our method should be fine.

Re: Testing Leaves For Starch

Posted: 01 Apr 2016, 09:34
by melsid
I have a teacher who is doing this prac today, she has ordered the hot plates, and beakers to use as water baths for the test tubes of metho.

I'm confident that it will be fine. :thumbup: