What is capillary attraction?

Capillary attraction is the power which liquids have of rising in very small tubes to a height above the level of the liquid in which such tubes are dipped.

In what kind of tubes will capillary attraction take place?

Only in tubes which the given liquid will moisten.

Why will not capillary attraction take place in large tubes?

Because in the large tube there is proportionately a less amount of surface in contact with the water, and in addition, there is a much heavier body of water which this force of attraction must lift.

Give common examples of capillary attraction.

The absorption of water by sugar and sand, the rising of sap in trees, the taking up of water by the sponge, etc.

How may capillary attraction endanger the trap seal?

If pieces of lint, sponge, or rags lodge in such a manner as to hang over the dip of the trap into the seal, unless soon renewed, the seal will be carried away drop by drop.

Why does water that has been heated freeze more readily than cold water?

Because by heating the water the air has been driven out.

Of what is water composed, and what are the proportions?

Water is composed of oxygen and hydrogen; one part oxygen, two parts hydrogen.

What other points are noticeable in pure water?

It is colorless, tasteless, and free from odor.

At what degree does water reach its greatest density?

At 39.2 degrees. It expands from this point, whether it be colder or hotter.

At what temperature does water freeze?

At 32 degrees.

At what temperature does boiling begin?

At 212 degrees.

Does water expand in freezing?

It does.

What force is exerted by frost?

A force of 30,000 pounds per square inch.

Name some freezing mixture.

Two parts of pounded ice and one part of common salt.

Why does the presence of oil in water prevent freezing?

Oil is a poor conductor of heat, and prevents heat from leaving the water.

Why does water burst a vessel by freezing as well as by heating?

At certain temperatures of heat and cold, water expands.

Will water absorb gases, and under what conditions is absorption greatest?

Water will absorb gases, and to the greatest extent when the pressure of the gas upon the water is greatest, and when the temperature is lowest, for the elastic force of the gas is then less.

Why is water called hard?

Because it is charged with foreign matter and will not readily dissolve substances immersed in it.

What makes water hard?

Generally from being impregnated with sulphate of lime. There are other impurities taken from the earth that have a similar effect.

Why is rain water soft?

Because it is not impregnated with the salts of the earth.

What is the object of filters?

Filters are designed to clear and purify the water of any foreign substance that may be in it. The most effective filters are of manufactured stone, the water being forced through them under pressure.