Page 14 - Curriculum Visions Dynamic Book

Lead metal
Lead is the heaviest of all the common metals. It is over 11 times as heavy as an equal volume of water. It is a plentiful (and therefore cheap) material, whose unreactive properties make
it useful for a wide range of applications. For example, it has been used for sculpture because it can be cast accurately.
The denseness of lead makes it a very useful material where compact weight is needed.
You will find small pieces of lead sewn into
the lower hem of some curtains to make them hang straight, and you will find lead in the bottom (keel) of a ship to balance the weight
of the superstructure and to help stop it from rolling over. Lead, which is soft and will absorb shocks, can also be used as mounting blocks for heavy machines to help damp down vibrations.
Lead will also absorb radiation, and it
has an important application in protecting radiographers and unexposed film from X-rays.
Lead shot
For a long time small pieces of lead – called lead shot – were used by fishermen and clipped on to the line below a float to hold the float and tackle in the correct position in the water. This was banned after it was discovered that birds ate the shot and got lead poisoning.
For many centuries lead has also been used to make the shot that was loaded into guns. It was an ideal material, easily made molten, heavy and yet small, so it could easily travel through the air with the minimum loss of speed.
Lead shot is made by pouring molten lead from the top of a high tower. As the lead falls, it breaks up into tiny globules that solidify in the cool air. The lead reaches the bottom of the tower as round lead shot, where its fall is broken in a tub of water or oil.
 Lead has a low melting point and can be used to make alloys suitable for fuse wires.
 Many lead compounds are insoluble.
They are also heavy and readily settle out as soon as they have been precipitated. The tiny granules of the precipitate can be seen as they settle to the bottom of the test tube. The only common soluble lead compounds are lead nitrate and lead acetate.
Like most bases, lead hydroxide is insoluble. This granular precipitate of lead hydroxide was made by reacting solutions of lead nitrate and sodium hydroxide.
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