Directions: Read both scenarios below and compare the two to answer the questions that follow.

How are the scenarios similar and how are they different.

what are the indepent, dependent, and control variables in scenario A


Scenario A

Alex conducted an experiment to determine the effectiveness of different metals releasing hydrogen gas from hydrochloric acid. He read that a local gas company was burying magnesium metal underground next to iron pipelines to prevent the pipes from rusting. Alex wondered if other metals would be effective in preventing pipes from rusting.


To investigate, he placed the following into individual test tubes each containing equal amounts of water from the same source: one iron nail, one iron nail wrapped with an aluminum strip; one iron nail wrapped with a magnesium strip; and one iron nail wrapped in a lead strip. He used equal amounts of metal strips and the same type of iron nails. After five days, he recorded the amount of rusting as small, moderate, or large for each material. He also recorded the color of the water.


Scenario B

Michelle was studying the vascular system of plants in school. She cut the bottom off of 2 celery stalks and placed one celery stalk in clear water and one celery stalk in the colored water. She left the celery in the cups for 24 hours. The next day, she noticed colored tubes in the celery stalk that was in colored water, which she identified as the xylem tissue. She cut off a piece of each celery stalk and observed it under a dissecting microscope to make her observations.