Question

Mrs. Cantrel's class wants to know if birds prefer seeds or bread. They set up two bird feeders outside of school and counted the number of birds that eat from each of the two bird feeders.

Is this an exper­iment or an observational study?

Answer 1

Mrs. Cantrel's class conducted an observational study by counting birds at feeders with seeds or bread, without manipulating variables. For an experiment, a biologist could play warning calls to see if birds respond, which requires controlled manipulation.

Step-by-step explanation:

Mrs. Cantrel's class set up two bird feeders to determine if birds prefer seeds or bread and counted the number of birds at each feeder. This is an example of an observational study because the students are not manipulating any variables but rather observing and recording the natural behavior of the birds. An experiment would require them to manipulate variables in a controlled way, such as by changing the type of food offered at different times and observing the birds' responses. In the scenario described, no such manipulation takes place; the birds are simply given a choice without any intervention.

To further investigate a biologist's hypothesis that birds recognize the predator warning calls of other species, an experiment could be designed where audio recordings of different bird species' warning calls are played near the feeders. By observing and recording the birds' reactions, the biologist could collect data on whether the birds respond to the calls, thereby testing the hypothesis. This would involve a level of control and manipulation that differentiates it from an observational study.