In this experiment, I will be testing the corrosion rate of copper wire after leaving them in different liquids with different pH levels. By doing so I will be able to determine which pH level corrodes copper the fastest. I will conduct this experiment by pouring 250mL of different liquids with different pH levels in cups, followed by an iron strip placed into the cup. A stopwatch will be timing how long it takes the iron strip to fully corrode. The cups will be placed in the same environment right next to each other in order for the cups to be in the same temperature. All of the cups will be the same type of cup to make sure the cups won’t have a role determining the results.
There will be three trials for each type of liquid. This will ensure the most accurate results. The pH level will be tested with a strip of litmus paper to determine the official pH level of the liquid. The stopwatch will start as soon as all of the copper wire are placed into the cups. I will be watching the cups, taking note of any qualitative data I see. When I see that the iron strip in one of the cups is fully covered in rust, I will record the time that was on my stopwatch. To analyze the data I will first find the average pH level for each of the liquids. Then I will average the total time it took for the copper wire to corrode. This data will be in hours. To see if there was any correlation between the independent variable and dependent variable, I will create a graph with the time it took the copper wire to corrode as the y-axis and the pH level as the x-axis.
Hypothesis: If the pH level is more acidic, than the iron strip will corrode at a faster rate. Independent Variable:
pH level of liquids
Dependent Variable: rate of corrosion of iron strip
Control: pH of 7 (Tap water)
• Same amount of liquid in each cup (50mL)
• Same sized copper wire (5″x3/4″x3/64″)
• Same type of cup
• Cups placed in same temperature
• Cups placed in same environment
• 12 copper wire
• 4 see through cups
• 150mL of vinegar
• 150mL of bleach
• 150mL of tap water
• 150mL of hydrogen peroxide
• Litmus paper
• Stop watch
• Paper towel
1. On the see through cups, label which liquid will be poured into them 2. Pour 50mL of the liquids into their corresponding cups. 3. Put litmus paper into each liquid to get official pH level. Record pH level. 4. Place iron strip into liquid, making sure it is completely surrounded by liquid 5. Start stopwatch as soon as the copper wire are placed into cup. 6. Observe the copper wire. Record down the time whenever one of the copper wire is fully covered in corrosion. 7. Once all the times are recorded empty the cups and rinse them out with water. 8. Repeat steps 2-7 two more times.
9. Find the average time it took to corrode the iron strip.
I will be testing how pH levels of liquids affect the corrosion rate of an iron strip. The independent variable for this experiment is the pH level of the liquid. I will be using four different liquids, each having a different pH level. I will be using tap water, which is neutral; salt water, which is generally slightly basic; bleach, a very basic liquid; and vinegar, a very acidic liquid. The tap water will serve as my control. Having a variety of pH levels helps to give me a better perspective on how much of a factor pH level is on corrosion rate. The dependent variable will be the time it takes the iron strip to fully corrode. The unit for this measurement will be minutes.