galvanized reinforcing mesh

Rusty nail experiment

You Will Need:

6 Test tubes or plastic cups, 6 Steel nails (avoid galvanised ones), Coke, Water, Lemon juice, Vinegar, Cooking oil. Optional: Saltwater, detergent, Adult supervision

Instruction

Set up the 6 test tubes or cups as shown in the picture above. This experiment is very much about variable testing!

Take a photo and write down your observations of each nail at the start of the experiment. This is also a good time to enter this into your own classroom blog!

Optional: Weigh each nail with an accurate scale at the start and the end of the experiment.

Optional: Try different nails in the same liquid… do they rust differently?

Over the coming days take recordings of each nail’s condition.

–Which nail showed rust first?

– If you were able to weigh each nail at the end of the experiment, was there any difference between the nails? Why?

This setup is just one way of running this classic rust experiment. You could also try the following experiment conditions too:

nail completely submerged in water vs. half submerged, nail completely submerged in water with a layer of oil over the top of it, nail in salt water vs. nail in pure salt

You could also try normal steel nails vs. steel wool to investigate the effect of surface area on rusting rates as well.

Why Does This Happen?

Rusting is the oxidation of metal, whereby the oxygen in the environment combines with the metal to form a new compound called a metal oxide. In the case of iron rusting, the new compound is called iron oxide… also known as rust!

This science experiment is all about controlling variables to explore which material will rust an iron nail first.

Variables to test

Try boiling the water… does this make the nail rust faster, slower or is there no impact on the rusting time?, What happens when you use different liquids?, If you scratch the nail first, will it rust faster or slower?, What if you use iron wool and iron filings instead?, Try galvanised nails

Further information

Rusting, also known as corrosion, is the reddish-brown layer formed over an iron when exposed to air and water. Rusting occurs mainly because of a chemical reaction between iron with water and oxygen in the air.

Simple formula…

Water + Oxygen + Iron =Rusting

The chemical reaction usually occurs very slowly and it is an oxidation process. Rusting can also occur on other metals such as copper and they may not always be called ‘rust’.

Rusting can also occur in water. The carbon dioxide gas in the air mixes with water to form a weak acid called carbonic acid. This acidified water can dissolve some of the iron and water begins to break down into oxygen and hydrogen. The free oxygen reacts with the dissolved iron to form iron oxide or rust.