Types of Measurements: Different Measurements

By Tiffany and Samantha

Qualitative Quantitative

The appearance of a sample in words (QUALITY)

Ex. Cold, Light, etc.

The amount with numbers (QUANTITY)

Ex. 18.3 cm, 10g, 4 min.

SI Units are used to measure in science• Temp. K Kelvin• Length M Meters• Mass Kg Kilograms• Volume L Liters• Time S Seconds

Good Measurements are true (accurate) and repeatable (precise)

Can you make a qualitative and quantitative measurement of the following?

.5 grams

20 grams

Accuracy and Precision:Information

By charlie zoeller, John Cornfield, & dylan Brooke

• When measuring, a measurement should be true and repeatable.

• This means that the information is accurate and precise.

Sample

•A textbook says that the density of an object is 10g/cm^3 but a student finds out its actually 8g/cm^3.• Is it accurate?

Yes- The student measured all sides of the book and multiplied them to get 8g/cm^3– Is it repeatable?

» No- Both the textbook and the students had different answers

Practice Problem

• Student one measures a sample of iron to be 3.34 g. Students two and three measure it to be 3.3g. Is student one correct?

Practice problem

• Yes, although the student rounded, the info is precise and accurate.

Sig Figs in MeasurementsBy Ian Quinn, Brian Sayre, and Jack

Weinberger

• Significant Figures are used to reduce the amount of guessing when making measurements.

• When measuring, you take all of the certain numbers, plus 1 estimated number.

Measuring using Sig Figs

• The last certain number on this graduated cylinder is to the tens place.

• We are certain that it goes to 17, but we have to take 1 estimated number past the last certain number. So we would get a measurement of 17.1

Measure the leaf, with Sig Figs!

3.59 cm

Multiplying and Dividing SigFigs: RulesMackenzie Saturn, Leah Edmonds and

Katelyn Ewell

• When multiplying and dividing, the number of SigFigs in your answer is the same as the least number of SigFigs in your measurement.

Examples-Multiplication

Questions:1. 250.mL x 5.6mL2. 50.54cm x 30cm3. 0.25g x 45g Answers:

1. =1400mL^22. =2000cm^23. =11g^2

Examples-Division

Questions:1. 50.54cm 4.1mL2. 1.278 x 10^3m 1.4267 x 10^2m 3. 7530g / 6.5g

Answers:1. =12cm/mL 2. =8.958m3. =1200g

Try it!

Questions:1. 8.91 x 27002. 5000. x 0.233. 2.90 1.74. 678 4

Answers:1. =240002. =12003. =1.74. =200

What is a Prefix?

• Prefixes are used to adjust the size of a metric unit.

Metric Prefix ConversionsBy: Julia Broadbent and Carolyn Belardinelli

Positive Prefixes

• Tera: T-10^12 (1,000,000,000,000)• Giga: G-10^9 (1,000,000,000)• Mega: M-10^6 (1,000,000)• Kilo: k-10^3 (1,000)• Hecto: h-10^2 (100)• Deca: da-10^1 (10)

Base Units

• Grams, Liters, Meters, etc.• They equal 1 unit

Negative Prefixes

• Deci: d-10^-1 (.1)• centi: c-10^-2 (.01)• milli: m-10^-3 (.001)• micro: -10^-6 (.0000001)• nano: n-10^-9 (.0000000001)• pico: p- 10^-12 (.0000000000001)

Sample Problems

1) 1nm=10^-9m

2) 14cm*10^-2m =1.4*10^-1m 1cm-write down # and unit given-put units to get rid of in denominator. Put units wanted in numerator -fill in the equality with correct units

Other Unit Conversions:Information/ How To

by Mark And Mike

• Converting a unit of measure to another unit of measure such as: inches-miles.

Sample Problem

• 3 feet=1 yard

• 12 feet to___ yards.

• 12 feet/ 3 feet 1 yard• Answer= 4 yards

Practice Problem

• ¼ mile= 15,840 inches

• 100,000 inches to ____ miles.

Answer

• 1.57 miles

What is Density?Maria Weck & Jessica Chu

• Density is a ratio of mass to volume• Density can be used to identify substances. • The density of a substance is always the same.• You can find density by dividing mass by

volume.• The units of each are… density=g/cm^3 or

g/mL, mass=g, volume=cm^3 or mL

Sample Problem

• If a 96.5g newspaper has a density of 2.7 g/cm3, what is its volume? • V = M ÷ D

Answer

•V= 35.74 cm^3

Percent ErrorBy Daniel Yu and Julian Wolak

• Percent error is stated as a percentage of the change between an approximate or measured value and an exact or known value.

• To calculate Percent error, you must use this formula:

|Accepted Value-Experimental Value|Accepted Value x 100%

Sample Problem

You calculate the density of an aluminum block and it is 2.68 g/cm3. Then you calculate the density in room temperature and the density is 2.70 g/cm3. Calculate the percent of error.

Sample Problem

2.68 – 2.702.70 X 100%

.02/ 2.70= .0074074

.0074074 X 100% = .74%

Percent of Error is .74% (expressed using 2 SigFigs)

Problem

• At a track meet, you time a friend running 100 m in 11.00 seconds. The officials time her at 10.67 seconds. What is your percentage error?

Answer

10.67-11.00 = -.33

.33/10.67= .03093 X 100%

Percent of error is 3.08%