This is a pet hate of mine and I was wondering what others think.
Firstly, some background, I've been a science teacher for nearly 20 years, before that I worked in a hospital microbiology lab so I am very aware of the need for genuine safety in the lab.
I make my students wear safety glasses if they're heating anything in an open beaker or tube, even water, or using any chemicals that are even vaguely hazardous.
However, I'm seeing a HUGE increase in safety instructions on worksheets etc prepared for schools with really SILLY safety warnings. I hate this, I think it's counter-productive. I want my students to know that if I give them a safety instruction it's because it's sensible. Stupid warnings, when they know something is safe is just like the story about the boy that cried wolf.
Here's an example from 2011.
http://sites.jmu.edu/chemdemo/2011/06/14/mm-color-wheel/In this demo suitable for younger students, all you use are cold water, M&Ms and a plastic petri dish, yet it tells them to wear safety glasses.
Why?
Do they use safety glasses to drink water or eat M&Ms outside the lab? Of course not, so they KNOW this experiment isn't hazardous in any way whatsoever, they know there is nothing to protect their eyes from.
I don't buy the argument that they should be in the habit of ALWAYS wearing them in the lab either, that's a nonsense, they should be taught to properly assess safety. I don't make them wear saftey glasses to write with pens during a theory lesson, why would I make them when they're just dissolving M&Ms in water?