What are Precious Metals?

We sometimes call valuable metals, such as platinum and gold, precious metals. Platinum is the most valuable metal in the world. It is called a catalyst because it produces a chemical reaction in other substances without itself changing. Platinum is more expensive than gold and is used in many industries. Another metal, iridium, is often used as a hardening agent for platinum.

Gold is the third most valuable metal after platinum and iridium. It can be rolled and stretched more than any other metal. Gold is used to make jewelry and some electronic equipment. Copper is often added to gold to make it harder.
Another precious metal is silver, which loses its shine, or luster, when exposed to the air. Silver must be polished to remove any stains. The photographic film in your camera contains silver, and many ornaments and pieces of jewelry are made of silver.

Read more

Homemade Air Thermometer – How to Make a Hom... The illustration shows the complete thermometer. The water in the glass tube is caused to rise and fall by the expansion and contraction of the air in...
Jack in the Box – How to Make a Jack in the ... A Jack in the box (Fig. 289) is a simpler toy to make than you might imagine. The box should measure about 5¾ inches by 5¾ inches by 5 inches. H...
How to Waterproof Canvas – method used by th... The method used by the British navy yards for waterproofing and painting canvas so it will not become stiff and cracked is as follows: One ounce of ye...
WHO INVENTED THE PARACHUTE? Imagine if you find yourself into an empty space at the height of 4-5 miles above the Earth, and yet you have landed on the ground as if you jumped fr...
Close Menu