Question

1. experimentation involves the testing of...

a) variables
b) conversions
c) laws
d) conclusions

1. the metric unit that would best measure the length of your thumb is...

a) m
b) in
c) cm
d) mm

1. an experiment is said to be \controlled\ when...

a) government policies specify the nature of the experiment.
b) the study includes the testing of a variable with a known and accepted result.
c) there are no dangerous substances used in the experiment.
d) two or more scientists give their approval to the design of the experiment.

1. convert 768,000mg into grams.

a) 384g
b) 0.768g
c) 384,000g
d) 768g

1. an example of a derived quantity is...

a) electric current
b) time
c) length
d) pressure

1. what will never be done with excess chemicals during an experiment?

a) dump down the drain
b) place in garbage
c) place back in original container
d) ask your instructor

1. how many significant digits are contained in the number 0.0046?

a) 4
b) 5
c) 3
d) 2

1. how many significant digits are contained in the number 65.500?

a) 5
b) 3
c) 4
d) 2

Explanation:

• Question 7: Experimentation in science is about testing variables. Laws are established principles, conversions are unit - related, and conclusions are the end - result of an experiment.
• Question 8: A thumb's length is best measured in centimeters. Meters are too large, inches are not metric, and millimeters are too small for a thumb's length.
• Question 9: A controlled experiment has a control group (testing a variable with a known result) to compare with the experimental group. Government policies are not relevant, dangerous substances are about safety not control, and multiple - scientist approval is about validity not control.
• Question 10: Since \(1g = 1000mg\), then \(768000mg=\frac{768000}{1000}g = 768g\).
• Question 11: Derived quantities are combinations of base quantities. Pressure (\(P=\frac{F}{A}\), where \(F = ma\)) is a derived quantity. Electric current, time, and length are base quantities.
• Question 12: Excess chemicals should never be dumped down the drain as they can cause environmental harm. Placing in garbage, putting back (if not contaminated), or asking the instructor are more appropriate actions.
• Question 13: Leading zeros (\(0.00\)) are not significant. The significant digits in \(0.0046\) are \(4\) and \(6\), so there are \(2\) significant digits.
• Question 14: Trailing zeros in a decimal number (\(65.500\)) are significant. The digits \(6\), \(5\), \(5\), \(0\), \(0\) are all significant, so there are \(5\) significant digits.

Answer:

1. a) variables
2. c) cm
3. b) the study includes the testing of a variable with a known and accepted result
4. d) 768g
5. d) pressure
6. a) dump down the drain
7. d) 2
8. a) 5