Units & Prefixes
Accuracy & Precision
Least Count
Scientific Notation
Scientific MethodCategory Name
100

Which unit would be most suitable for measuring the length of a classroom?

A. Millimetres
B. Centimetres
C. Metres
D. Kilometres

C. Metres

100

Which word means “close to the accepted or true value”?

A. Precision
B. Accuracy
C. Reliability
D. Least count

B. Accuracy

100

What is the least count of a measuring instrument?

A. Its largest possible measurement
B. The smallest measurement or division it can show
C. The average of several measurements
D. The amount of error in every measurement

B. The smallest measurement or division it can show

100

Write 6,700m in scientific notation.

6.7×103m

100

Which step usually comes first in a scientific investigation?

A. Conclusion
B. Question
C. Results
D. Evaluation


B. Question

200

What does the prefix kilo- mean?

A. 10
B. 100
C. 1,000
D. 0.001


C. 1,000, or 103103

200

Which word means that repeated measurements are close to one another?

A. Accuracy
B. Precision
C. Validity
D. Estimation


B. Precision

200

A ruler has markings every 1 mm. What is its least count?

A. 1 cm
B. 10 mm
C. 1 mm
D. 0.1 mm

C. 1 mm

200

Write 0.0045 kg in scientific notation.

4.5×10-3 kg

200

Which statement is the best hypothesis for this question?

Does water temperature affect how quickly sugar dissolves?

A. Sugar is interesting.
B. Hot water is useful.
C. If the water temperature increases, then sugar will dissolve faster.
D. The experiment will use a cup.

C.

300

Convert 3.2 km into metres.


 3.2×1,000 = 3,200m

300

The accepted value is 50.0 g. A student records:

49.9 g, 50.0 g, 50.1 g

Are the results accurate, precise, both, or neither? Explain.

Both accurate and precise.

  • They are close to the accepted value.
  • They are also close to one another.
300

A measuring cylinder has markings every 2 mL. What is its least count?

What is the smallest difference between two measurements that the scale directly shows?

The least count is 2 mL, so the smallest directly shown difference is 2 mL.

300

Write the following as an ordinary number:

8.3×104


83,000

300

A student investigates whether the amount of sunlight affects plant growth.

Identify:

  1. The independent variable
  2. The dependent variable
  1. Independent variable: the amount of sunlight
  2. Dependent variable: plant growth, such as plant height
400

A race is 2.75 km long. Express the distance in:

  1. Metres
  2. Centimetres
  1. 2,750 m
  2. 275,000 cm275,000 cm
400

The accepted value is 50.0 g. A student records:

44.0 g, 44.0 g, 44.1 g

Are the results accurate, precise, both, or neither? Explain.

Precise but not accurate.

  • The measurements are close to one another.
  • They are far from the accepted value.
400

A ruler has a least count of 1 mm. A student records the length of a pencil as:

12.347 cm

Is this an appropriate measurement? Explain and give a more appropriate way to record it.


No. The measurement is recorded with too many decimal places for a ruler with a least count of 1 mm.

Acceptable recordings include:

  • 12.3 cm
  • 123 mm
400

A student writes 45,000 in scientific notation as:

45×103m

Is this written correctly? If not, correct it.

It is not written correctly because the first number in scientific notation must be at least 1 but less than 10.

Correct answer:

4.5×104m

400

A student investigates whether water temperature affects how quickly sugar dissolves.

Give:

  1. One controlled variable
  2. One reason for repeating the experiment

Possible controlled variables:

  • Amount of sugar
  • Volume of water
  • Type of sugar
  • Stirring method
  • Container used

Reason for repeating:

  • To improve reliability
  • To identify unusual results
  • To reduce the effect of random error
  • To check whether the results are consistent
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