* Research question: From all of the metals Iron, Copper, Tin, Aluminium, Lead, Nickel, used in the architecture of a building, which of these metals will corrode the least when acid rain reacts with these metals?
* Background Information :Acid rain is caused by air pollution when fossil fuels such as coal, oil or natural gas is burnt and when smoke is emitted from industries into the air. Sulfur dioxide and nitrogen oxides which is present in the smoke, reacts with the water and the other chemicals in the air to form nitric acid(HNO3) and sulfuric acid (H2SO4) which falls down to the earth’s surface as acid rain and since it is corrosive, it causes damage to buildings, sculptures and to other forms of infrastructure.
* Theory: Metals such as, Copper, Tin, Aluminum, Lead, Nickel, will corrode or dissolve in the acid when it reacts with acid rain causing the mass of the metal to decrease. It also causes the metal to rust which makes it useless for the building.
All the metals, will decrease in their mass when reacted with acid rain so to measure which metal is destructed the most, the loss in mass for all the metals over a fixed period of time will be used for investigation.
* Materials used for the experiment:
* 3000 ml of acid rain for investigation.
* 1000 ml (ï¿½ 5 ml) measuring cylinder for measuring the amount of acid rain used.
* 100 g of solid Tin chips.
* 100 g of solid copper chips.
* 100 g of solid Iron chips.
* 100 g of solid Lead chips.
* 100 g of solid nickel chips.
* 100 g of solid Aluminium chips.
* 30 large beakers of 100 ml(ï¿½ 0.5 ml) each.
* Pan balance (ï¿½0.001 gram)
* 5 litres of distilled water.
* Variables for the experiment:
* Independent Variable: The independent variable of the experiment is the metal used for each trial of the investigation to obtain the data. This is the only factor which will be kept changed for all the experiments.
Each metal will be measured by weighing 10 g by using the pan balance for each trial.
* Dependent variable: The dependent variable is the loss in mass over the time given for the metal to dissolve in the acid rain. As this will depend on the metal used. As the metal which has the greatest weight loss, that metal would be the one which should not be used for a metal in building. The metal with the least loss should be used.
The loss in mass of the metal will be measured in grams by weighing all the beakers with a pan balance with acid rain in it and adding the metal to the acid rain forming a solution and weighing it. After the fixed amount of time kept, weigh the final amount of the beaker. The difference between the initial and the final mass of the beaker with the contents will be the loss which is the dependent variable.
* Constants of the experiment: The constant factors of the experiment are the time given for the decrease in mass for all the 6 metals. The mass of each metal used is kept constant for all the trials. The volume of acid rain used is also kept constant for all the trials.
* Controlling the variables:
To control the variables of the experiment, the metals, will be placed in distilled water to ensure that it does not get dissolved in normal water and only gets eaten away in acid rain so that the metal used will be tested first to see whether it will dissolve in acid rain to achieve the best possible result.
* Procedure of the experiment:
1. Measure out 100 ml of distilled water with the measuring cylinder and pour it into the beaker.
2. Weigh the mass of the beaker with the water in it with a pan balance.
3. Take Iron chips and weigh 10 g of it with a pan balance and place it in the beaker.
4. Weigh the beaker with these contents as the initial weight and cover it with a lid.
5. Start the time and keep the time as 30 minutes for the experiment.
6. Repeat steps 1 to 5 for Copper, Tin, Aluminium, Nickel, and Lead.
7. After 30 minutes, weigh the mass of the beaker with its contents.
8. Record the change in mass.
9. Repeat steps 7 to 9 for Aluminum, Copper, Tin, Lead and Nickel.
10. Measure out 100 ml of acid rain with the measuring cylinder and pour it into the beaker.
11. Weigh the mass of the beaker with the acid rain in it with a pan balance.
12. Take Iron chips and weigh 10 g of it with a pan balance and place it in the beaker.
13. Weigh the beaker with these contents as the initial weight and cover it with a lid.
14. Start the time and keep the time as 30 minutes for the experiment.
15. Repeat steps 10 to 14 for Copper, Tin, Aluminium, Nickel, and Lead.
16. After 30 minutes, weigh the mass of the beaker with its contents.
17. Record the change in mass.
18. Repeat steps 7 to 9 for Aluminum, Copper, Tin, Lead and Nickel.