This semester I'm the lucky professor who has three labs. One day a week, I have a morning lab and an afternoon lab with a lecture sandwiched in-between). My morning lab went smoothly, especially for the first lab of the semester for freshmen. No breakages. No weird products. They probably were the best group I've ever had for the first lab.
Then the afternoon lab began. As soon as one group picked up their evaporating dish, it was dropped and broken.
A little later I smelled something burning. I discovered a group who had melted a rubber policeman into their sample. Burnt rubber smells awful. Not to mention that their sample now had pieces of burnt rubber in it.
Later another group's watch glass exploded and broke. Nothing like having to pick up pieces of glass, weighing, and hoping to recover some of your sample.
We ended the day with a bang. The product should have been table salt. That's not what one group had. They had yellow crystals that gave off awful fumes. I sent them to the fume hood with their mystery product.
Needless to say, lab took the full time.
Maybe this group got all of the mishaps out of their system the first week of lab.
Here's to hoping!