Introduction
Corrosion is the oxidation of metals by materials in their environment. Rust is the corrosion of iron by oxygen in a moist environment. Corrosion has many effects on the properties of metals, corroded buildings, or machinery can develop weaknesses that result in malfunctions or breakages. Corroded metal can also not conduct electricity, which again can interfere with the functions of that metal.
Aim: the aim of this experiment is to evaluate the effect that sodium chloride has on the rate of corrosion of iron.
1. Experiment 1
2. Hypothesis: An increase in the level of sodium chloride in water will increase the rate of corrosion of an iron nail.
3. The independent variable is the amount of sodium chloride in the water
4. The dependent variable is the rate of corrosion; this will be measured by calculating the percentage of the nail that is corroded.
5. Apparatus/equipment needed:
5 iron nails 5 280 ml glass containers 750 ml of tap water 5 teaspoons of common salt 1 teaspoon
6. Method:
1. Wash each nail to remove any traces of grease or dust, and then rub each nail with steel wool.
2. Fill each of the glass containers with 150ml of the tap water
3. Mix ½ a teaspoon of salt in one container until dissolved
4. Repeat the process with 3 of the other containers increasing the amount of salt used by ½ a teaspoon each time so the 2nd will have 1 teaspoon, 3rd 1½ teaspoon, and the 4th 2 teaspoons. Leave one container with no salt in it.
5. Put 1 nail in each of these solutions
6. Leave the nails in these conditions for 5 days, recording observations and results each day
Things to be kept constant: Temperature of the water Quantity of water