1. What is a metal? Nearly 75% of all elements are metals.
Common characteristics of metals:
Conduction – of heat and electricity
Malleable – can be bent into different shapes
Ductile – can be pulled into a wire
Often shiny

2. Alloys Homogeneous mixture of 2 or more metals (solid solution).
Usually developed because they have more desirable properties than the element itself.

3. Examples of Alloys: Examples: Bronze: made of copper and tin
Brass: made of copper and zinc
Steel: made of iron and carbon
Stainless steel: made of iron, chromium and carbon

4. Pennies: What are they made of? Copper is increasingly expensive.
Until 1983, pure copper
Copper is increasingly expensive.
Since then … zinc with a THIN coat of copper

5. “Gold” Penny Lab: What are the “silver” pennies?
Regular penny with a thin coat of zinc on top.
How will you make “gold” pennies?
Zinc-coated penny is BRIEFLY heated in the Bunsen burner.
Heat melts the zinc coating and the surface of the copper coating.
These metals mix to form brass.
Warning: Hot metal looks like cold metal