1. Introduction to Biology

Jonathan wants to know which style/model of paper airplane is going to win the contest by traveling the furthest. He designs 5 different models of paper airplanes and drops each of them from the same height of 20 meters. He records the distance that each plane travels before it hits the ground. What are the independent and dependent variables of Jonathan's experiment?

            Independent Variable: ______________________________________ 

            Dependent Variable: _______________________________________

In an experiment to test the effect of temperature on bacterial reproduction rate, temperature would be the:

The temperature at which an alligator's egg is incubated will determine the sex of the offspring. The dependent and the independent variables in this experiment are ________.

A scientist wants to study the effects of nitrogen on wheat plants. They set up an experiment with 4 groups of plants: group A gets 20 pounds of nitrogen per acre, group B gets 40 pounds per acre, group C gets 60 pounds per acre, and group D gets 0 pounds per acre. Which of the following is the control group? Is it a positive or negative control group?

What does it mean to say that experimental conditions are controlled? Select True or False for each statement.

T/F The test groups consist of the same individuals.

T/F The null hypothesis is correct.

T/F There is no difference in outcome between the control and experimental treatment.

T/F All physical conditions except for one are identical for all groups tested.

A controlled experiment is one that

a. Proceeds slowly enough that a scientist can make careful records of the results.

b. Tests experimental and control groups in parallel.

c. Is repeated many times to make sure the results are accurate.

d. Keeps all variables constant.