Page 27 - Curriculum Visions Dynamic Book. To close the book, close the tab.

 Lead – Lead is a very heavy metal and
is often used as a weight, provided there is
no risk of pollution. These pictures show two hydrometers, instruments for measuring the density of a liquid by seeing how far down they will float. The lead acts as a compact weight. The picture above shows a hydrometer in use. The picture on the left shows a detail of the lead weights in a hydrometer of slightly different design.
Galena, lead sulphide
 Lead – Lead is a soft metal with a relatively low melting point.
Lead–Oneof the common ores of lead is galena, lead sulphide.
Lutetium (Lu)
This coating (similar in effect
to the coating that develops on copper) then helps prevent further reaction, and so corrosion happens very slowly. This has made it suitable as a roofing material and to protect underground cables. In the past it was made into water pipes. Lead also goes into making the plates for storage batteries, such as those in cars.
It makes low-melting point alloys, such as solder and pewter. Lead will absorb and protect from sound and radiation. At one time it went into an antiknock ingredient in gasoline. But it is poisonous and so now has been taken out of gas and water pipes.
Lead is mainly found in the mineral lead sulphide (also called galena).
Light elements
Hydrogen and helium on the periodic table.
Lithium (Li)
Element 3 on the periodic table. A member of the alkali metals (group 1 elements).
Lithium is a soft, white, shiny metal. It was discovered in 1817 by Johan August Arfwedson.
Lithium is alloyed with aluminium, lead and other soft metals to make them harder. It is also used in some batteries.
Lutetium (Lu)
Element 71 on the periodic table. A transition metal belonging to the lanthanides and also a rare- earth metal.
Lutetium was discovered in 1907 by Carl Auer von Welsbach and Georges Urbain. The name for the element comes from the Latin word for Paris. It has no important practical use.
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