I think you are talking about cleats. If that is the case then yes, they are safer than metal but wear out sooner. Also the shoe must be the interchangeable kind.
The easy answer is, "to cap test tubes and flasks." The real answer is, rubber stoppers are used in the lab because the rubber in them is unaffected by most chemicals - and unlike the glass stoppers that used to be standard in laboratories, they don't get stuck in the container.
rubber stoppers are used for a variety of things cars, door stops, test tube caps, brakes, and printer rollers
Commonly, rubber stoppers are used in scientific experiments to plug and test tubes. Their purpose is to prevent liquids, and sometimes gases, from escaping their containers.
Commonly, rubber stoppers are used in scientific experiments to plug and test tubes. Their purpose is to prevent liquids, and sometimes gases, from escaping their containers.
If they appear to be in good condition, then NO, do not replace them.
use to cover the test tube
NO!
The density of rubbers stoppers can be very different from one to the next. This is because there are different stoppers at different densities.
Normally cork or rubber is used as a stopper in a flask.
There are many formulations of rubber, so it depends on which formulation of rubber you use. Pharmaceutical rubber stoppers are made of Butyl rubber which is unaffected by alcohol.
Because they are not expensive, can assure a convenable sealing, are flexible, resist a long time, many reagents doesn't attack rubber, can support temperature in a wide range, the contaminatiom from the rubber is minimal, etc. Of course rubber stoppers are not recommended for all experiments.
use to cover the test tube, basically like a cork.