Unit 1.5 The International System of Units

Question 1

What is the International System of Units (SI)?

Answer 1

– Established in 1960
– Essentially a modernized metric system
– Official system of units for science
– Imperial system is NOT part of the SI system

Question 2

SI base unit for mass

Answer 2

– kilogram (kg)
– Will use gram (g) as the base unit in the course

Question 3

SI base unit for length

Answer 3

metre (m)

Question 4

SI base unit for time

Answer 4

second(s)

Question 5

SI base unit for electric current

Answer 5

ampere (A)

Question 6

SI base unit for temperature

Answer 6

Kelvin (K)

Question 7

SI base unit for amount of substance

Answer 7

mole (mol)

Question 8

SI base unit for luminous intensity

Answer 8

candela (cd)

Question 9

What was the origin of the Fahrenheit temp scale?

Answer 9

– Developed in 1717 by Gabriel Fahrenheit
– Designated the temp of a bath of ice melting in a solution of salt as the zero point on his scale

Question 10

How does the Fahrenheit temp scale work?

Answer 10

– The upper point is based on water’s boiling point, designated as 212°
– The melting point of ice is designated as 32°
– Degrees are based on an English tradition of using 12 divisions

Question 11

What was the origin of the Celsius Scale?

Answer 11

– Developed in 1742 by Anders Celsius

Question 12

How does the Celsius temp scale work?

Answer 12

– Based on the water melting + boiling points under normal atmospheric conditions
– The current scale is an inverted form of the OG scale, which was divided into 100 increments. So, the scale is AKA the Centrigrade Scale.

Question 13

What was the origin of the Kelvin Scale?

Answer 13

– Developed in 1848 by Lord Kelvin

Question 14

How does the Kelvin temp scale work?

Answer 14

– Uses molecular energy to define the extremes of hot and cold
– Absolute zero (0 K) corresponds to the point at which molecular energy is at a minimum
– Preferred in scientific work, though Celsius is also common
– Temps measured on the Kelvin scale are K, not °K

Question 15

What is the difference between water’s freezing point and boiling point on both the Celsius and Kelvin scales?

Answer 15

100°

Question 16

Both a °C and a K are ____ the size of a °F

Answer 16

9/5

Question 17

How are kelvin and celsius related?

Answer 17

– The kelvin is the same size as the celsius degree
– T (in °C) + 273 = T (in K)
– T (in K) - 273 = T (in °C)

Question 18

Celsius absolute zero, freezing point, boiling point

Answer 18

– -273°C
– 0°C
– 100°C

Question 19

Kelvin absolute zero, freezing point, boiling point

Answer 19

– 0 K
– 273 K
– 373 K

Question 20

How are Fahrenheit and Celsius related?

Answer 20

– The only temp for which the numerical value is the same for both scales is: 40°C and -40°F
– °C = 5/9(°F - 32)
– °F = 9/5(°C + 32)

Question 21

What are derived units?

Answer 21

– Any units that require math.
– A unit of measurement derived from the seven SI base units.

Question 22

Why would scientists assign a new derived unit in the place of base units?

Answer 22

To reduce inconvenience and clutter of the consistent base unit usage

Question 23

SI derived unit for mass

Answer 23

Name: tonne
Symbol: t
Written w/ base units: 1 * 10^6 g

Question 24

SI derived unit for volume

Answer 24

Name: litre
Symbol: L
Written w/ base units: 1 * 10^-3 m^3

Question 25

SI derived unit for force

Answer 25

Name: Newton
Symbol: N
Written w/ base units: kg*m/s^2

Question 26

SI derived unit for energy

Answer 26

Name: joule
Symbol: J
Written w/ base units: N*m or kg/ms^2

Question 27

SI derived unit for pressure

Answer 27

Name: pascal
Symbol: Pa
Written w/ base units: N/m^2 or kg/ms^2

Question 28

What are prefixes and its purpose?

Answer 28

– Placed in front of a base unit and represent a multiplying factor
– Allows for expression of large and small quantities

Question 29

What is the prefix giga?

Answer 29

– G
– 10^9 or 1,000,000,000

Question 30

What is the prefix mega?

Answer 30

– M
– 10^6 or 1,000,000

Question 31

What is the prefix kilo?

Answer 31

– k
– 10^3 or 1000

Question 32

What is the prefix hecto?

Answer 32

– h
– 10^2 or 100

Question 33

What is the prefix deka?

Answer 33

– da
– 10^1 or 10

Question 34

What is the prefix deci?

Answer 34

– d
– 10^-1 or 0.1

Question 35

What is the prefix centi?

Answer 35

– c
– 10^-2 or 0.01

Question 36

What is the prefix milli?

Answer 36

– m
– 10^-3 or 0.001

Question 37

What is the prefix micro?

Answer 37

– μ
– 10^-6 or 0.000 001

Question 38

What is the prefix nano?

Answer 38

– n
– 10^-9 or 0.000 000 001

Question 39

What is the acronym for metric conversions?

Answer 39

kats hate dogs __ dogs chase mice

Question 40

Why did so many of the world adopt the metric system?