unit 2 test 1

Describe three safety procedures you should always follow when conducting a scientific investigation.

Before you begin a scientific investigation you should always check your tools for chips or breaks. You should keep your work surface neat and clean, and you should read and follow safety instructions included with any materials you will use in the investigation.

When conducting an investigation outside, you can assume it is safe to touch any plant or animal you see.

False

JoAnne conducts an experiment to test whether or not plant growth is affected by the use of bottled water instead of tap water. She uses two plants in her investigation and waters one with bottled water and one with tap water. She keeps the amount of sunlight the plants receive, the pots they are planted in, the amounts of water they receive, and the type of soil they are planted in constant. How can JoAnne improve her experiment design?

JoAnne should use more than two plants. She needs more than one trial to ensure reliable, accurate data.

Jose writes the following hypothesis: If a rose bush receives nitrogen rich fertilizer then it will produce more roses than a rose bush that does not receive nitrogen rich fertilizer. Which of the following is a true statement about Jose's hypothesis?

Jose's hypothesis is both testable and falsifiable.

A student conducts an experiment to determine how the addition of salt to water affects the density of the water. The student fills 3 beakers with equal amounts of water. He then adds 1 cup of salt to the first beaker, 2 cups of salt to the second beaker and no salt to the third beaker. What is the dependent variable in the student's investigation?

The density of the water.

Which of the following best describes the dependent variable?

The variable that responds to change.

Which statement best describes an independent variable?

The variable you change in an investigation.

A variable can be measured using numbers and units and can also be answered by making observations that result in simple "yes" or "no" answers.

True

After recording the data for five repeated trials, you should calculate the average of the five values and report that average in your lab report.

True

Explain why it is important to keep all variables that might affect the dependent variable, other than the manipulated variable, constant.

Variables that can affect the dependent variable must be kept constant so that you know the changes in the dependent variable are only the result of the changes made to the independent variable.