Question

Two different underground pipe coatings for preventing corrosion are to be compared. The effect of a coating (as measured by maximum depth of corrosion penetration on a piece of pipe) may vary with depth, orientation, soil type, pipe composition, etc. Describe how an experiment that filters out the effects of these extraneous factors could be carried out.

Short answer

To filter out the effects of extraneous variables like depth, orientation, soil type, and pipe composition when comparing two corrosion-preventing pipe coatings, pairs of pipes with the same properties can be used. One pipe in each pair is treated with one coating, and the other with the second coating. After a set period of time, the maximum depth of corrosion is measured on each pipe. Any difference can be attributed to the effectiveness of the coatings, as all other factors are held constant.

Step-by-step solution

Defining Independent and Dependent Variables

In this experiment, the independent variables are the two different pipe coatings. The dependent variable is the maximum depth of corrosion penetration on a pipe which we're going to measure to determine the effectiveness of the coatings.

Controlling Confounding Factors

Though we can't eliminate extraneous factors such as pipe depth, orientation, soil type and pipe composition, we can control them. This can be done by taking pairs of pipes with the same properties (same depth, orientation, soil type and composition), coating one pipe from each pair with the first coating, and the other with the second coating.

Setting Up the Experiment

For each pair, bury both pipes in identical conditions. Objective is to ensure that each pair of pipes are subjected to the same external factors, differing only in the type of coating used.

Measuring the Effectiveness of the Coatings

After a set period of time, inspect and measure the maximum depth of corrosion penetration in each pipe. Because all the other factors were controlled, any difference in corrosion penetration can be attributed to the effectiveness of the coatings.

Key concepts

Independent Variables

In an experiment, the independent variables are the factors that the experimenter manipulates to observe their effect on the outcome. In our case, the primary independent variable is the type of underground pipe coating used. There are two different coatings that we want to compare. By varying the coatings applied to the pipes, we aim to investigate how each impacts corrosion resistance. This manipulation allows us to explore potential differences in performance between the two coatings, as these are the only variables intentionally changed during the experiment.

It's essential to keep other factors constant when manipulating the independent variable. This ensures that the observed effects on the dependent variable are due to changes in the independent variable alone.

Dependent Variables

A dependent variable in an experiment is what you measure in response to changes in the independent variables. For our corrosion study, the dependent variable is the maximum depth of corrosion penetration observed on the pipes. This measurement reflects the effectiveness of each type of pipe coating in preventing corrosion.

After applying different coatings, we will measure the depth of corrosion in order to understand which coating offers the best protection. The change in corrosion depth will show how each coating performs under identical environmental conditions. By analyzing these measurements, we can draw conclusions regarding the efficacy of each coating in combating corrosion.

Controlling Confounding Factors

Confounding factors are variables that can interfere with the results of an experiment, making it hard to identify the true relationship between the independent and dependent variables. In our pipe corrosion experiment, confounding factors include pipe depth, orientation, soil type, and pipe composition. Ensuring these factors remain constant across samples is crucial for reliable results.

To control confounding factors, we take pairs of similar pipes—same depth, orientation, composition, and buried in the same soil type. Each pipe in a pair is coated with a different type of coating. This setup ensures that any variation in corrosion depth is due to the coating itself and not other differences.

By controlling for these extraneous factors, we eliminate potential sources of error and bias, increasing the validity of our findings.

Measurement of Effectiveness

Measuring effectiveness in an experiment involves assessing how well an independent variable achieves its intended outcome. Here, the effectiveness of the pipe coatings is determined by evaluating their performance in preventing corrosion. This is done by measuring the maximum depth of corrosion penetration on the coated pipes after a specified period.

The procedure involves using appropriate tools to measure corrosion depth accurately. By comparing these measurements across different coatings, we can identify which coating is more effective at preventing corrosion under the controlled conditions of the experiment.

• After measurement, data analysis can be conducted to check for statistically significant differences in corrosion depth between the coatings.
• Effectiveness conclusions are drawn based on the comparative performance of each coating, taking into account any controlled variables.

This methodical approach helps ensure that our conclusions are based on solid, empirical evidence.