Warning: Nitric acid is very corrosive and toxic. Do not contact it or let it contact any organic materials. The fumes produced are highly toxic. Do not inhale them.
You will need:
One or more of these: lithium, calcium, magnesium, aluminium, zinc, iron, nickel, tin, lead, copper, silver, gold
Dilute nitric acid
Lots of test tubes
For consistency, all of the metals should be about the same shape and size. Zinc powder will react more vigorously than an aluminium chunk, even though aluminium is higher on the reactivity series.
In an earlier post (http://lanthanumkchemistry.over-blog.com/article-reactivity-series-demonstration-part-2-77468092.html), I showed the reactivity series by immersing metals in hydrochloric acid (well, lithium floated) and observing their reaction. The corrosion is not observable for all metals, so nitric acid, as an oxidizing acid, will increase the number of metals able to dissolve. Aqua regia, a mixture of nitric and hydrochloric acids, is even stronger, but it does not dissolve silver because a passivating layer is formed.
Place nitric acid in all of the test tubes. Add the metals. Here the fun starts. The more reactive metals such as magnesium, calcium, zinc, aluminium, and lithium will release plain old hydrogen gas. The less reactive metals, though, such as copper, iron, lead, tin and nickel will begin releasing nitric oxide gas, which oxidizes to the brown choking nitrogen dioxide. Even silver dissolves, although gold is untouched. If you are using your silver jewelry, take it out before it completely dissolves in the nitric acid.