SI Units & Conversions

Question 1

What is qualitative data?

Answer 1

Descriptive data without numbers. Observations about qualities or characteristics. Examples: color, texture, smell, “the water is hot.”

Question 2

What is quantitative data?

Answer 2

Numerical data with measurements. Examples: 25°C, 5.2 meters, 10 kg.

Question 3

How do you quantify a measurement?

Answer 3

Attach a number AND a unit to the observation. Example: instead of “the table is long,” say “the table is 2 meters long.”

Question 4

What are the 7 fundamental SI units?

Answer 4

Length (meter, m), Mass (kilogram, kg), Time (second, s), Electric current (ampere, A), Temperature (kelvin, K), Amount of substance (mole, mol), Luminous intensity (candela, cd).

Question 5

SI unit for length?

Answer 5

meter (m)

Question 6

SI unit for mass?

Answer 6

kilogram (kg)

Question 7

SI unit for time?

Answer 7

second (s)

Question 8

SI unit for electric current?

Answer 8

ampere (A)

Question 9

SI unit for temperature?

Answer 9

kelvin (K)

Question 10

SI unit for amount of substance?

Answer 10

mole (mol)

Question 11

SI unit for luminous intensity?

Answer 11

candela (cd)

Question 12

Why are units arbitrary?

Answer 12

They’re human-made choices/conventions. We could measure length in feet or meters—what matters is consistency and agreement on the standard.

Question 13

What is a derived unit?

Answer 13

A unit made by combining fundamental units. Examples: velocity (m/s), acceleration (m/s²), force (kg·m/s² or N).

Question 14

What is the derived unit for velocity?

Answer 14

meters per second (m/s) = length/time

Question 15

What does “standard” mean for SI units?

Answer 15

An agreed-upon, official definition that everyone uses for consistency. Example: the meter is defined by the distance light travels in a specific fraction of a second.

Question 16

Metric prefix - peta (P)

Answer 16

10¹⁵ = 1,000,000,000,000,000 (quadrillion)

Question 17

Metric prefix - tera (T)

Answer 17

10¹² = 1,000,000,000,000 (trillion)

Question 18

Metric prefix - giga (G)

Answer 18

10⁹ = 1,000,000,000 (billion)

Question 19

Metric prefix - mega (M)

Answer 19

10⁶ = 1,000,000 (million)

Question 20

Metric prefix - kilo (k)

Answer 20

10³ = 1,000 (thousand)

Question 21

Metric prefix - hecto (h)

Answer 21

10² = 100 (hundred)

Question 22

Metric prefix - deca (da)

Answer 22

10¹ = 10 (ten)

Question 23

Metric prefix - BASE UNIT

Answer 23

10⁰ = 1 (meter, gram, liter, etc.)

Question 24

Metric prefix - deci (d)

Answer 24

10⁻¹ = 0.1 (tenth)

Question 25

Metric prefix - centi (c)

Answer 25

10⁻² = 0.01 (hundredth)

Question 26

Metric prefix - milli (m)

Answer 26

10⁻³ = 0.001 (thousandth)

Question 27

Metric prefix - micro (μ)

Answer 27

10⁻⁶ = 0.000001 (millionth)

Question 28

Metric prefix - nano (n)

Answer 28

10⁻⁹ = 0.000000001 (billionth)

Question 29

Metric prefix - pico (p)

Answer 29

10⁻¹² = 0.000000000001 (trillionth)

Question 30

Metric prefix - femto (f)

Answer 30

10⁻¹⁵ = 0.000000000000001 (quadrillionth)

Question 31

Metric prefixes from largest to smallest (abbreviations)

Answer 31

P, T, G, M, k, h, da, (base), d, c, m, μ, n, p, f

Question 32

How do prefix values help with conversion?

Answer 32

The exponent tells you how many places to move the decimal. Example: to convert 5 km to m, kilo = 10³, so multiply by 1000: 5 km = 5,000 m. To convert 3000 m to km, divide by 1000: 3000 m = 3 km.

Question 33

General steps to convert?

Answer 33

New number = Old number × 10^(starting exponent - ending exponent) Or just: move the decimal by the difference in exponents