All About Alloys

There are some familiar metals that are actually mixtures of several different types of metals - they are called alloys (AL-oise). Here are a few you've probably heard of (and some that are likely new to you):

• Steel: mixture of iron and one or more other metals (there will be a separate post about steel later)
• Brass (copper and zinc): a shiny yellow metal that looks a little like gold
• Bronze (copper and tin): a dark gold to brown metal that gets darker in color as it ages
• Pewter (copper, tin, and lead): a dark gray metal used for bowls, flatware, jewelry and other decorative items
• Solder (lead and usually tin): an alloy that melts at a relatively low temperature; used to make electrical circuits
• Nitinol (nickel and titanium): this alloy remembers its original shape; used to make eyeglass frames
• Electrum (gold and silver): also known as white gold; used in jewelry
• Alnico (aluminum, nickel, and copper): used to make magnets
• Amalgam (silver, tin, copper, zinc, and mercury): a soft alloy that has been used to fill dental cavities
• Nichrome (nickel and chromium): an alloy that glows orange-red and gives off heat when an electrical current is passed through it; used in toasters and electric burners

Take a look around your house and see how many examples of alloys you can find!

Fun Facts 11

And finally...

• In the early 1900's, glow-in-the-dark watches were made with paint that contained radium (Ra, #88). Many of the young women who made these watches became very sick because of their exposure to this radioactive element.
• Lutetium (Lu, #71) is probably the most expensive element you've never heard of! It costs more than gold or even platinum!
• Did you know that your pencil doesn't actually contain lead? The stuff you write with is carbon (C, #6) in the form of graphite.
• Humans have been using the metal iron (Fe, #26) for thousands of years. There is a 1500-year old iron pillar in Delhi, India that is still rust-free, probably because it is located in an area with a dry climate.
• The nibs (tips) of very expensive pens may be made with rhodium (Rh, #45) because it does not wear down easily.
• Gas camping lanterns often use a compound of thorium (Th, #90) which glows bright white when heated.
• Rechargeable batteries often contain both nickel and cadmium (Cd, #48). They are called nicad batteries.
• Tin (Sn, #50) slowly disintegrates in temperatures below freezing (32^oF or 0^oC). In the 1700's, organs in unheated churches could be destroyed because their tin-containing pipes would turn brittle and crumble.
• Barium (Ba, #56) X-rays can be used to detect problems in the stomach or digestive tract. Barium sulfate does not let X-rays pass through, so after you drink a barium cocktail, those parts of your body become visible.
• The catalytic converter in your car contains palladium (Pd, #46) which helps to reduce the amount of pollution that comes out of the exhaust pipe.