Question

cam and rosario decided to perform an experiment on the oxidation of metals for a class project.

they created the hypothesis, \if iron, copper, and zinc are exposed to water and air, then iron will oxidize the fastest.\

they then researched different metals and how they react to water and air.

during their research, they found an article that confirmed their hypothesis.

cam and rosario then determined that iron oxidizes faster than copper or zinc and presented their findings to the class.

select the statement that best describes their experiment.

this experiment is complete. it has all of the elements necessary and the conclusion is valid.

this experiment does not have a cause and effect hypothesis

this experiment is missing a testing and data phase. without a testing phase, their conclusion is based on the work of other people.

this experiment is missing research. several stages of research should occur at various stages of the process.

Explanation:

1. Analyze the first option: A valid experiment should include testing (conducting the experiment to collect data) and analyzing that data. Cam and Rosario only found an article confirming their hypothesis, not their own experimental data, so the experiment is not complete. Eliminate this option.
2. Analyze the second option: Their hypothesis is "If iron, copper, and zinc are exposed to water and air, then iron will oxidize the fastest," which is a cause - effect (exposure to water and air is the cause, oxidation rate is the effect) hypothesis. Eliminate this option.
3. Analyze the third option: The scientific method for an experiment includes forming a hypothesis, testing (conducting the experiment to get data), analyzing data, and drawing conclusions. Here, they skipped the testing phase (they didn't perform the oxidation experiment themselves) and relied on an article. So this statement is correct.
4. Analyze the fourth option: They did research (found an article), so this option is incorrect.

Answer:

This experiment is missing a testing and data phase. Without a testing phase, their conclusion is based on the work of other people.