# Significant Figures - PC|MAC

Significant Figures There are two kinds of numbers: Exact Inexact Example: There Example: Any are twelve eggs measurment in a dozen

If I were to measure a piece of paper, I might get 20.15 mm You might get 20.14 mm. Somebody else may get 20.16 Who is right ????? Precision vs. Accuracy Accuracy Precision

- Refers to how - Refers to how closely individual measurements agree with each other closely a measured value agrees

with the correct value Remember..there is uncertainty in all measurement but the precision is determined by the measuring device. In any measurement, the number of significant figures is the number of digits believed to be correct by the person doing the measuring It also includes one estimated digit.

Here are 3 examples of when sig. figs. are important when measuring volumes in the lab. A beaker A graduated cylinder

A buret A rule of thumb: Volumes should be read to 1/10 of the smallest division. Example: If the smallest division is 10 mL, the volume would be read as having an error of 1 mL. A Beaker

The smallest division is 10 mL-so we can read the volume to 1 mL. The volume in the beaker is 47(+ or ) 1mL. It might be 46it might be 48. So, how many sig. figs.???? (2) - The 4 we know for sure, plus the 7 that we had to

The smallest division is 1 mL so we can read the volume to 0.1 mL. The volume could be read as 36.5 (+ or -) 0.1 mL. The true volume could be 36.4 or 36.6. How many sig. figs??? (3)- The 3 and 6 we know for sure- the 5 had to be estimate. A Buret

The smallest division is 0.1 mL so we can read the volume to 0.01 mL. A good volume reading would

be 20.38 (+ or -) 0.01 mL. An equally precise answer would be 20.39 or 20.37. How many sig. figs.???? (4)- The 2, 0, and 3 we know for sure, the 8 we had to estimate. Conclusion: Significant figures are directly linked with measurement. Now, how do we determine significant figures?

Determining the number of sig. figs. in a number. Picture a map of the U.S. If a decimal point is present, count from the Pacific side. Start counting with the first nonzero digit. All digits from here to the end, including zeros, are significant. Examples:

Answer: 2 If the decimal point is absent, start counting from the Atlantic side. Start with the first nonzero digit. All digits from here to the end, including zeros, are significant.

Significant Figures in Calculations: Rules for Multiplication and Division The answer contains no more significant figures than the lease accurately known number. Examples: The number with the

least # of sig. figs. has 2 sig. figs. Therefore, the answer must have 2. The number with the least # of sig. figs. has 3 sig. figs. Therefore, the answer must have 3. Rules for Addition and Subtraction The number of sig. figs. is determined by the location of

digits in the number with the largest uncertainty, not the number of significant figures in the number. Examples: The least precise number is 2.02. It has sig. figs. out to the hundredths place. Therefore the answer will have sig. figs. out to the hundredths

place. The least precise # (1.0236) has decimals carried out 4 places. Therefore the answer will have sig. figs. carried out 4 decimal places.

## Recently Viewed Presentations

• Paper 1: Shakespeare and 19th Century Prose (Macbeth and A Christmas Carol) 1 hour 45 minutes. Paper 2: Modern Text and Poetry (An Inspector Calls, Anthology and Unseen Poetry) 2 hours 15 minutes. ENGLISH LITERATURE
• Arial Wingdings Calibri Times New Roman Edge 1_Edge 2_Edge Networks and Distributed Systems Technology Trends Distributed Systems Promises of Distributed Systems Reality of Distributed Systems Network Technologies Broadcast Networks Arbitration Aloha Network Aloha Network Aloha Network Blind Broadcast Ethernet (introduced...
• MOSAIC analysis. Echo top height. 1 Jul 2014, 00Z. The para WRF-ARW has broader coverage in 25-40K foot range (pale blue colors) WRF-ARWcomposite reflectivity. Equitable Threat Score. Bias. bias=1. Grid-to-grid verification against radar mosaic. 10. 20. 30. 40. 50. 10....
• Foundations in Low-Rise Construction (up to 3 floors) The function of a foundation. A foundation is designed and constructed to safely transmit the loads of the building to the ground or sub-soil. They should be able to support the loads...
• Current Topics in Ethics and Social Responsibility OS 386 September 19, 2002 Fisher Agenda Discuss current issues, using corporate examples Be ready to discuss your example In-class writing Reminder: Written Case Study Due September 24 Select Case Study 3.2 OR...
• Do Now: Matching Review The Rise of Persia The Persians based their empire on tolerance and diplomacy. They relied on a strong military to back up their policies. Ancient Persia is where Iran is today. Aim: How did the Persians...
• Model Fit Statistics Intercept Intercept and Criterion Only Covariates AIC 63.827 59.244 SC 65.633 62.857 -2 Log L 61.827 55.244 Testing Global Null Hypothesis: BETA=0 Test Chi-Square DF Pr > ChiSq Likelihood Ratio 6.5830 1 0.0103 Score 6.4209 1 0.0113...
• Those were the mighty men who were of old, men of . renown. Genesis 6:4. Was Achilles one of these? Other Greek demi-gods? Nehemiah. Ruth (Ruth 4:13-17) Rahab ... Agrippa I. 70 Destruction of . Jerusalem by Titus. Titus. Domitian....