Science: Nail Corrosion

 Hi there!

Today I will be writing about the experiment I did in Science class as a part of what I am studying, Metallurgy. 

Aim: 

To investigate how different things make iron nails corrode. 

Method: 

1. Get a test tube rack and six test tubes. 

2. Place an iron nail wrapped in tinfoil in the first test tube. 

3. In the next, place a nail inside fill it up with water until it covers the nail, then place a layer of oil on top of the water.

4. In the third test tube, place the nail inside, then put a small spoonful of Calcium Chloride powder and place a bung (test tube plug) on top of the tube. 

5. In the fourth test tube, place water inside the tube, approximately enough to cover the nail once it is placed, next mix in a couple of spoonful's of salt and mix it until dissolved, then place the nail. 

6. In the fifth test tube, place a nail covered in nail polish inside. 

7. In the last test tube, place a nail inside and cover it fully with water. 

8. Leave it undisturbed for at least 3 days.

Results/Observations:

Here is a photo of my test tubes, right after I set them up:

Here are photos of the test tubes after leaving them alone for about 5-7 days:

Left to right: tinfoil, water+oil, calcium chloride + bung, salt water, nail polish, water 

Left to right: tinfoil, water+oil, calcium chloride + bung, salt water, nail polish, water 

Discussion:

In order for iron corrosion, or rusting to occur there must be two things present, water and oxygen. When either of these is removed, no rusting can happen. Iron doesn't need to be under water to rust because majority of the time there is some water in the air. There is also always a small amount oxygen that has been dissolved in water too. Salt speeds up rusting, that is why there is more rusting on iron in coastal areas of New Zealand, not inland. 

Luckily, rusting can be stopped, or at least slowed down. The most obvious answer is to keep water and oxygen away from each other, but then we would not be able to use iron. So, the following are used to protect iron from rusting over:

- Paint. Paint is used because it coats the iron, protecting it from moisture and oxygen.

- Zinc. Coating iron with zinc, or galvanising it prevents rusting too. The zinc forms an impenetrable surface cover of zinc oxide which resists rust. 

- Grease. Grease is a sticky, water-repelling substance that also stops oxygen from reaching iron. 

The nail wrapped in tinfoil showed little rusting. It still had rusting because there was moisture trapped inside as well as some air too. 

The nail which was cover with water and then a layer of oil had little rust on the nail, but lots of rust coloured speckles next to the layer where the water and oil met. 

The nail with the calcium chloride powder and bung on top didn't show any rusting. This happened because it had not access to water or oxygen. 

The nail with salt water had rust around the nail, as well as some rust floating at the top too. 

The nail with nail polish didn't show any signs of rust. This happened because it was coated, so the oxygen and water couldn't reach it. 

The nail in regular water showed the most signs of rust. It had lots of rust on the nail and lots of speckles of rust floating around in the water.

Conclusion: 

This experiment worked, I was able to see the effects of corrosion on iron nails with different substances. Next time, I would like to test more substances and they corrode iron nails to widen my knowledge. I really enjoyed this experiment, it was a change having to wait for the results, rather than knowing straight away. 

Thanks for reading!