Question

1. The Scientific Method is a linear list of steps that begins with making observations and developing a hypothesis and ends with either proving or rejecting one’s hypothesis based on experimental evidence.

True

False

2. Scientific discoveries are often the result of collaboration between several researchers.

True

False

3. Which of the following is a testable hypothesis?

- Flamingos stand on one.

-Does a sunflower grow taller when exposed to 6 hours of sunlight a day or 8 hours of sunlight a day?

- Children who get exercise 30 min./day, 5 days a week are 3x less likely to become obese than those children who receive no exercise over the same 5-day period.

- If chickens lay eggs, then do all birds lay eggs?

4. Consider the following experimental design:
Hypothesis: Increasing levels of nitrogen in the soil leads to retarded growth (i.e., shorter height) of Kentucky Bluegrass

Experiment:
1. Pure Kentucky Bluegrass grass seed will be planted and grown in a Greenhouse under identical conditions (e.g., same amount of water, same amount of sunlight, same temp., etc.).
2. Once the grass is one week old, nitrogen pellets will be added to the soil in varying quantities (as shown in the table below).
3. Plant height will be recorded over a 6-week period.
4. Average grass height will be calculated for each group.

Group	#1 (20 pots)	#2 (20 pots)	#3 (20 pots)	#4 (20 pots)
Treatment	5 nitrogen pellets	10 nitrogen pellets	15 nitrogen pellets	20 nitrogen pellets

What was the dependent variable in this experiment?

Group of answer choices

- Number of nitrogen pellets added in each group

- Number of groups

- Average height of Kentucky Bluegrass plants in each group

- There is no dependent variable in the above experiment

5. For the same experiment as the preceding question (Kentucky bluegrass), what was the independent variable?

Group of answer choices

- Identical conditions (e.g., same amount of water, same amount of sunlight…)

-Number of nitrogen pellets added in each group

-Average height of Kentucky Bluegrass plants in each group

- Six

For the same experiment as the preceding two questions (Kentucky Bluegrass), the researchers conclude that increased nitrogen pellets lead to taller Kentucky Bluegrass. Is this a well-supported conclusion?

Group of answer choices

- No, because the experiment lacked a control group

- No, because the experiment lacked a dependent variable

- Yes, because the data clearly shows that increasing the number of nitrogen pellets increases the height of the grass.

Answer 1

Ans1) true

Explaination :the given statement is true as the step in scientific methods are in following order:

• Making observation
• Asking question or stating statement of problem regarding observation.
• Formulating a hypothesis
• Testing of hypothesis through experiments
• Accepting or rejecting hypothesis on the basis of result of experiments.

Ans2)true

Explaination: the statement which states that Scientific discoveries are often the result of collaboration between several researchers.

Ans3) Testable hypothesis are:

Does a sunflower grow taller when exposed to 6 hours of sunlight a day or 8 hours of sunlight a day?

- Children who get exercise 30 min./day, 5 days a week are 3x less likely to become obese than those children who receive no exercise over the same 5-day period.

Ans4) dependent variable:

Average height of Kentucky Bluegrass plants in each group

Explaination: dependent variabe is the possible outcome of interest in experiment and depend on independent variable.

Here increase in height of kentucky bluegrass plants in each group is the possible outcome of interest in this experiment and its value changes with dependent variable ie, no. of nitrogen pellets added so Average height of Kentucky Bluegrass plants in each group is dependent variable.

Ans5)independent variable:

Number of nitrogen pellets added in each group

Explaination: independent variable is a variable which itself being manipulated to alter the dependent variable.

Here Number of nitrogen pellets added in each group differ and with increase in no of nitrogen pellets in each group the height of grass is the possible outcome.

So here Number of nitrogen pellets added in each group is the independent variable.

Ans6)No, because the experiment lacked a control group

Explaination: control group is important in experiment to justify its results. Control group does not include independent variable.