Question

Explain the working of hourglass​

Answer 1

Answer:

As its name indicates it is very hard and have high melting point. It is also more resistant to action of acids. Uses:- Hard glass is used for making hard glass laboratory apparatus. It is prepared by fusing potassium carbonate, lead oxide and silica.

Answer 2

Hourglass. Hourglass, an early device for measuring intervals of time. It is also known as a sandglass or a log glass when used in conjunction with the common log for ascertaining the speed of a ship. It consists of two pear-shaped bulbs of glass, united at their apexes and having a minute passage formed between them.