What are the uses of the following laboratory apparatus:
1. water trough;
2.hard glass tubes; and
3.water bath

There is a homework board for such questions !

Can't do homework, but glass tubing is used to transfer acids. You can use it as a pipette or a pipe from one vessel to another. Hospitals and areas that have acid wash areas actually have glass pipes in the walls and floor for the plumbing. Glass is very acid resistant.

I suppose a "water trough" keeps the water off the bench!

Glass tubing has practically infinate uses in a chemisty lab - generally it is used because it is inert to mose chemicals. It's also useful for piping gases around. Personally, I prefer teflon tubing, 'cause it doesn't break (and cut me!).

Water bath is useful for controlling temperature. Immersing a reaction flask in an ice water bath gives you some control over reaction rate, for example. Also used during some recrystallizations. A hot water bath can be particularly useful for heating (low boiling) flammable solvents under reflux - water won't start a fire if something goes wrong.