ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Measurement: The basis of all scientific work

Updated on December 3, 2014


Upon completion of this lesson, the students should be able to:

  1. develop the skills in making accurate and precise measurement
  2. recognize the equivalents of the prefixes used in the SI units
  3. demonstrate skills in using dimensional analysis in conversion units

Measurement is used in the laboratory to take the temperature of a given substance.
Measurement is used in the laboratory to take the temperature of a given substance.
Measurement is used to take the mass or weight of a given substance.
Measurement is used to take the mass or weight of a given substance.
Measurement is used to get the volume of liquids.
Measurement is used to get the volume of liquids.

What is measurement?

Measurement is the process of finding out how many units there are in something. The basis of all scientific work is measurement. There are various units of measurement depending on what we wish to measure. There are measurements of length, mass, force, volume, time, velocity, density, electric current and many others and these are expressed in different units.

Almost all of us use measurements. The food we eat, the clothes and shoes we wear, the work we do, and many of the games we play involve measurements.

Some of the basic measurements in the chemistry include the following:

How long?

How big?

How heavy?

How hot?

What is scientific notation in measurement?

Scientific notation has the form M x 10n where M is the number between 0 and 10 and n is a positive or negative integer. n is the exponent or power of the number. It expresses the number of times 10 is multiplied by it.

Rules in writing a number in scientific notation:

  1. Retain one digit before the decimal point.
  2. Multiply M by 10 raised to the proper value of n, where n is equal to the number of decimal places the point is moved.
  3. Positive exponent means the decimal point was moved to the left.
  4. Negative exponent means the decimal point was moved to the right.

Example: The mass of the atmosphere is 5 100 000 000 000 000 tons, write it in scientific notation.

5 100 000 000 000 000 tons = 5.1 x 1015 tons


Significant figures

Significant figures

Significant figures are numbers that are either certain or good estimates of numbers. All numbers greater than zero are significant. A zero, which is part of a measurement, is significant. A zero used just to locate a decimal point is not significant. Only the same number of decimal places as the term with the least number of significant figures. The numbers are rounded off to give the proper number of significant figures.

Rules in rounding off figures

  1. If the figure to be dropped is greater than 5, increase by one the value of the last figure to be retained.
  2. If the figure to be dropped is less than 5, the last figure to be retained should not be changed.
  3. If the number to be dropped is 5, the last figure to be retained is increased by one if it odd, and retained as is, if it is even.

International System of Units (SI Units

The present system of units used is the International System of Units known as the SI Units, which is the revision and extension of the metric system.

SI Base Units

Electric Current
Amount of Substance
Luminous Intensity

Derived Units

cubic meter or liter
m3 or l
kilogram/cubic meter
Speed or Velocity
moles/cubic meter
N (kg m2/s2)
J (kg m2/s2)
W J/s2
Quantity of electricity
coul (As(
Electric potential


Indicate the SI base units appropriate to express the following:

  1. length of a 100 mile race = kilometer
  2. mass of the horse = kilogram
  3. volume of a swimming pool = cubic meter
  4. speed of a racing car = kilometer per hour
  5. density of metallic gold = grams per cubic centimeter
  6. area of a basketball court = square meters
  7. the maximum temperature at the North pole on April 1, 1913 = Kelvin

Table of Prefixes

When the name of the unit is preceded by a prefix, that decimal multiplier modifies the size of the unit.


a. 1um = _____cm

= _____mm

1um x 10-6 m x 1cm = 10-4 cm

1um 10 m

1um x 10-6 m x 1mm = 10-3 mm

1um 10 m

Conversion of Units: Dimensional Analysis

Using the dimensional analysis or factor-label method simplifies the conversion between various units. If units are treated like numbers, they can be multiplied, divide or cancelled. A conversion factor which is written in the form of ratio is used to change the units given in the data to the units asked for in the answer.

given quantity x conversion factor = desired quantity


1. Convert 8.0 inches to cm

Given: 8.0 inches

Conversion factor: 1 inch = 2.54cm


8.0 in x 2.54 cm = 20.32 cm

1 inch

2. Convert 15cm to km

Given: 15 cm

Conversion factors:




103 m


15cm x 1m­­­_ x 1km­_ = 15/105 km or

102cm 103 m 15 x 10-5 km

Conversion Chart

Equivalence between units


1 in = 25.40 mm

1 in = 2.54 cm

1 ft = 30.48 cm

1 m = 39.37 in

1 A (Angstrom) = 10 m


1 oz = 28.35 g

1 lb = 453.6 g

1 kg = 2.2 lb


1 qt = 0.946 l

1 gal = 3.785 l

Laboratory Measurements:

Laboratory experiments require measurements of length, mass, volume, and temperature. Meter is the unit of length. Kilogram is the unit of mass. Second is the unit of time. Kelvin is the unit of thermodynamic temperature. The natural unit of capacity is based on a standard unit of length. Volume is length cubed (P). The most common unit of volume used in chemistry is the liter. Density is the mass or quantity of matter of a substance contained in one unit of its volume.

Density = mass per unit volume = mass of body/volume of body

Specific gravity (Relative Density) = mass of solid or liquid/mass of an equal volume of water


Temperature is a measure of how hot something is. It is usually measured with a thermometer has a scale that gives an amount of hotness a certain number value. There are two common scales of temperature, the Fahrenheit scale and the Celsius scale. Extremely high temperature may be measured with a pyrometer. Aside from showing how hot an object is, temperature is a measure of the kinetic energy (energy of motion) of molecules that make up an object. When energy is added to an object, the additional energy usually increases the kinetic energy of the molecules and the object gets hotter. For example, energy is added to a gas as it is squeezed, to a liquid as it is stirred, and to a solid as it is hammered. A thermometer shows this increase in energy as a rise in temperature.

Formulas used in the inter conversions of the scales:

ºC = 5/9 (ºF – 32)

ºF = 9/5 ºC + 32

ºK = ºC + 273


1. The normal body temperature is 98.6 ºF. What is the temperature in degrees Celsius and Kelvin?

Conversion Factors: ºC = 5/9 (ºF – 32)

ºK = ºC + 273

ºC = 5/9 (98.6 – 32) = 5/9 (66.6) = 37.0 ºC

ºK = 37.0 + 273 = 310ºK

2. Convert 30 ºC to ºF.

Conversion Factor: ºF = 9/5 ºC + 32

ºF = 9x30/5 + 32 = 86ºF


A. Solve the following:

1. Complete the following:

a. 13g = _______________________ kg

b. 3451 mg = ___________________g

c. 4.18 g = _____________________mg

d. 17.38 km = ___________________cm

2. A 170 cm track and field athlete weighs 49.8 kg. Is she more likely to be a distance runner or a shot putter?

3. Gasoline is sometimes sold by the liters. How many liters are required to fill a 10.0 gallon gas tank?

4. The distance between the centers of two oxygen atoms in an oxygen molecule is 1.21 A. What is this distance in centimeters and inches?

5. Calculate the density of aluminum if 13.8 cm3 has a mass of 37.3 g.

6. What is the mass of the following?

a. 6.00 cm3 of bromide; density = 2.928 g/cm3

b. 1000 ml of octane; density = 0.702 g/cm3

B. Search on the internet a research conducted on chemistry, chemical industries, or new chemical products.

Chemistry Lesson: Significant Digits & Measurements


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)