Significant Digits (Figures)

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Significant Digits (Figures)

• Significant digits represent the amount of
  uncertainty in a measurement. digit that is
  actually measured or estimated will be considered
  significant.
• E.g. The length of something is between 5.2 and
  5.3 cm. Suppose we estimate it to be 5.23 cm.

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Significant Digits

• The first 2 digits (5 and 2) are certain but the
  last digit (0.03) was estimated. Therefore, the
  measurement 5.23 has 3 significant digits.

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Significant Digits Rules

• All non-zero digits (1-9) are considered
  significant
• e.g. 123 m3 s.d., 23.564 s.d.

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Significant Digits Rules

• 2) Zeros between non-zero digits are also
  significant
• e.g. 1207 m 4 s.d., 120.5 km/h 4 s.d.

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Significant Digits Rules

• 3) Any zero that follows a non-zero digit and is
  to the right of the decimal point is significant.
  
• e.g. 12.50 m/s 4 s.d. because it shows that we
  actually measured that digit to be 0.
• 60.00 km 4 s.d.

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Significant Digits Rules

• 4) Zeros used to indicate the position of the
  decimal are not significant.
• e.g. 500km 1 s.d., 0.325m 3 s.d., 0.00034km
  2 s.d.

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Significant Digits Rules

• 5) All counting numbers have an infinite number
  of significant digits because we are certain of
  the exact number
• e.g. 6 apples infinite s.d.