Hector carried out an experiment to see if adding calcium powder to soil made plants grow taller. He took two potted plants and put calcium powder into only one of the pots. He gave each plant the same amount of sunlight and water and measured their growth after five weeks.
Based on his results, Hector claimed that calcium powder makes plants grow faster.
Which best describes his claim?
It is valid because his experiment had clear variables.
It is invalid because his sample size is small.
It is invalid because his claim is not based in science.
It is valid because he is an expert in his field.
It is invalid because his sample size is small.
After a scientist wrote up her findings in a paper, she submitted it to a journal for peer review. After the review, it was accepted.
What happens to the paper in the next step of the peer-review process?
It becomes a part of the accepted research.
It is returned to the author.
It gets published.
It needs to be rewritten.
It gets published.
Which is a characteristic of a scientific claim?
it is supported by a controlled experiment with multiple trials that can be repeated by others
it is another way to describe the controlled variables in an experiment.
it involves an experiment with multiple variables that can be repeated by others
it is an if-then statement that predicts the most likely results of an experiment
It is supported by a controlled experiment with multiple trials that can be repeated by others.
Which would be the most reliable source for information?
the Center for Disease Control website
Wikipedia, an online publicly edited encyclopedia
updates from a Twitter account
an editorial on a new drug
The most reliable source for information would be the Center for Disease Control website.
Which claim would most likely be considered valid?
a company that says its vitamin water has tested better than most energy drinks
a wildlife biologist who states that human expansion is destroying migration lands of birds
a doctor who says a certain brand-name drug is best because he has a contract with the drug maker
a newspaper that writes stories with opinions similar to the political views of the editor
The claim that would most likely be considered valid is the one made by the wildlife biologist who states that human expansion is destroying migration lands of birds.
The best description for Hector's claim would be:
"It is invalid because his sample size is small."
Explanation: In order for a claim to be valid, it needs to be supported by sufficient evidence. Hector's experiment only involved two plants, which is considered a small sample size. A larger sample size would have provided more reliable and generalizable results. As a result, Hector's claim cannot be considered valid due to the limitations of his experiment.