So far, I have only had two experiments with the Form 4 students -- the first one was about plant cells, and the second one was about osmosis. And today I had the first experiment with the Form 3 students. We were supposed to do the experiments to determine the solubility of compounds and the reaction of a certain compounds with heat.
The solubility experiment - nothing to worry about la. They just needed to add distilled water into boiling tube that contains salts like iron oxide, copper carbonate, etc.
The best part of the whole experiment this morning was.. POP! EXPLOSION!
Honestly, I am that kind of freako who imagines what are some of the bad stuff that might happen in the given situations. And when it comes to heating chemicals, I am a little worried about that.. what if the chemicals explode, what if this happens, what if that happens..
It was my first lesson of the day. The students were supposed to heat the iron sulphide to produce sulphur dioxide gas which will turn the potassium manganate (VII) from purple to a colourless solution because the gas is acidic....
I assigned 3 groups of students to carry out that part of the experiment. First two groups started while the 3rd group was taking their own sweet time. Both groups had the same problem but one of the groups, I named it The Romans *because one of the boys named Roman*, had the best experience of the day where their boiling tube broke. *oh my god....*Let me explain to you the situation.
Materials and Apparatus : you have a boiling tube that contains iron sulphide (i gave it a yellow colour), then the boiling tube is connected to the test tube via delivery tube. The test tube contains potassium manganate (VII) which is purple in colour. The delivery tube has to be in the purple solution so that gas will straight enter into the solution.
Observe the diagram, box #1:
The Romans set up the apparatus as it is shown in the diagram and began to heat the iron sulphide.
I was at the other table monitoring the other group. This group of girls was the first to start heating. They heat the iron sulphide and the sulphur dioxide gas was channeled into the potassium manganate (VII) solution. Then we decided to stop the fire. It was truly my mistake that I didn't FIRST remove the test tube that contains the purple solution BEFORE turning off the fire. I saw the back flow of purple solution up into the delivery tube and in my heart I was like *oh my god.. shucks....!!!!!!!!* Good thing was, I managed to move the test tube away before more potassium manganate can flow into the boiling tube to cause an explosion. SAVED.
But the Romans weren't that lucky.
Box#2: While I was busy saving the girls... the Romans started heating the boiling tube. They placed the Bunsen burner on a stack of books. I saw and of course I told them to take away the books lar...so, they shifted the books together with Bunsen burner, away!!!
Box#3:
And then I was in my *Oh my god* mode again!!
I saw the purple solution rushing into the boiling tube and I was like....
Oh nooooooooooooooooo....!!!
I told them to move the test tube away... but they were too stunned and slow to respond and.....and i quickly rushed to their table and tried to move the test tube and ...
POPPPPPPP!
Box#4
A piece of glass about 1cm diameter broke and popped out from the boiling tube and fell to the floor. Smoke began to form. Some of us began to cough because of the gas that was released and purple powder all on the table and retort stand. My oh my. Thank God no one was hurt and it was just a MINI explosion....
I can't stop telling them how lucky we were *if lucky is the right word*. I was kind of traumatised by the whole incident. And seriously, I am glad that I am not teaching Chemistry. I can't imagine that kind of fear that I will have to live with if I am a Chemistry teacher. :p
Well... that's the drama I had..
The other class was also supposed to do the same experiment. Haha, I just cut off the heating part. Poor kids can only do the part on solubility.
I am still traumatised by the whole thing, k..... sheeeeshhhh
A piece of glass about 1cm diameter broke and popped out from the boiling tube and fell to the floor. Smoke began to form. Some of us began to cough because of the gas that was released and purple powder all on the table and retort stand. My oh my. Thank God no one was hurt and it was just a MINI explosion....
I can't stop telling them how lucky we were *if lucky is the right word*. I was kind of traumatised by the whole incident. And seriously, I am glad that I am not teaching Chemistry. I can't imagine that kind of fear that I will have to live with if I am a Chemistry teacher. :p
Well... that's the drama I had..
The other class was also supposed to do the same experiment. Haha, I just cut off the heating part. Poor kids can only do the part on solubility.
I am still traumatised by the whole thing, k..... sheeeeshhhh
1 comment:
This reminds me of a rather dramatic incident back when I was in Form 4.
We were doing the part on oxidation, heating a metal strip in a crucible. Our labs have gas piping, and so the Bunsen burners we use are the sort you have to 'plug in' to the pipes using a tube.
During the heating, we were crowded around the apparatus in one corner of the lab, and I was sitting next to the tap. Suddenly, I (or was it one of my friends?) somehow dislodged the tube from the tap, causing an immediate gas leakage.
The air around the tap and apparatus spontaneously burst into flames. Our reflexes must've been quite instant, as all I can remember was: leak - fire - jump away two metres.
Some of the hairs on our hands were singed off.
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