mbalax - 7-10-2016 at 07:51
Hi there
Just a quick classroom question for any practising teachers out there, I'm new into teaching and need hazard advice.
I'm getting students to make a saturated copper sulfate solution and leave it over the weekend in petri dishes to evaporate the water and make
crystals.
Is it OK just to leave it out on windowsills in the lab, or is copper sulfate toxic enough to need to transfer it to the school's prep room as we
always do with acids or more obviously dangerous chemicals?
cheers
Mbalax
Texium - 7-10-2016 at 08:04
Leaving it on the windowsill is perfectly fine, especially since it will just be over the weekend when there aren't any students around who could
possibly knock it over.
Copper sulfate is really only appreciably toxic by ingestion, so it's not something that you need to be too concerned about as long as your students
don't stick their fingers in their mouths, and wash their hands after handling it.
Sulaiman - 7-10-2016 at 08:14
do you not have MSDS for chemicals that you expose your students to ?
your students have already passed the most dangerous stage ... powder, an eye irritant.
aga - 7-10-2016 at 08:24
Obviously consider/act on all the obvious stuff, and enforce general safety rules (eye protection, gloves etc).
In the normal world, a windowsill is fine.
As it is a Teaching environment, get into the ass-covering thing asap.
Inform all the parents & students (via a take-home leaflet) of all the risks & safety precautions before the event.
Do something like stick a BIG sign up that says something like "Toxic Chemicals. Do Not Touch, Eat, Pour into eyes or Smear on sensitive body parts.
Call 0898555555 in case of Emergency".
Texium - 7-10-2016 at 08:48
This may be a matter of personal philosophy, but I think that if you regularly overstate the dangers of working with tame chemicals like copper
sulfate, one of two things will happen, and neither of them are good:
1. You'll breed paranoia and chemophobia among your students and they won't feel comfortable in a lab because they feel like everything can
potentially kill them. They'll enter the lab with apprehension rather than excitement and probably not enjoy the experiment. This mindset has the
potential to turn away students who could have been future chemists had they been given a more reasonable outlook.
2. You'll set up a "boy who cried wolf" scenario, where your students will not take you as seriously in the future when you warn them about the
hazards of a chemical that actually is very toxic or corrosive, and they will not be as careful with it as they should be. Say in the future they were
to work with mercuric chloride. The hazards would probably sound very similar on paper to those of copper sulfate, but we know that in reality
mercuric chloride is far more dangerous.
MrHomeScientist - 7-10-2016 at 10:50
I'm with zts16. Read over the SDS (you should have already as part of the planning process) and inform your students of the actual hazards of the
substances you're working with. Instruct them on standard lab safety before handling anything: don't eat it, don't drink it, if it gets on you wash it
off with soap and water, always wear gloves and goggles. Then talk about the specific hazards of your experiment - copper sulfate is an irritant, can
possibly stain things, and is very toxic for aquatic life. So don't pour it down the drain or into any ponds or sewers, and if anyone spills on
themselves just rinse it off.
I always tell kids that safety in the lab comes in 3 steps: if you get something on you, (1) Don't Panic, (2) tell your partner and the teacher, and
(3) go to the sink and rinse it off right away.
Finally have you considered disposal? What will you do with leftover solution? I usually add baking soda to form (basic) copper carbonate, which can
be thrown away more safely.
CharlieA - 7-10-2016 at 18:11
I would interchange steps 2 and 3 for most cases.