science unit 2

Kg (Kilogram)

S.I. unit for mass

s (second)

S.I. unit for time taken

m (Metre)

S.I. unit for length

K (Kelvin)

S.I. unit for temperature

Density

It is the amount of matter an object has in proportion to its volume.

How to find density?

m/v (mass divided by volume)

either g/cm³ or g cm-³

unit for density

derived quantities

Measurements that require you to calculate them. Example: Area = length x base x height

base quantities

Measurements that only have to be taken once. Example: Length, mass, time taken, temperature

How are the S.F. and D.P. rules applied?

For addition, subtraction and average, leave your answers to LEAST NUMBER OF DECIMAL PLACES.

example → 1.2 + 0.456 =1.7 (round of to 1 d.p)

For division, multiplication and other operations, leave your answers to LEAST NUMBER OF SIGNIFICANT FIGURES.

example → 5.25 × 10 = 53 (2 s.f.)

prefix for 10³

k (kilo)

prefix for 10^6

M (Mega)

prefix for 10^-1

d (deci)

prefix for 10^-2

c (centi)

prefix for 10^-3

m (milli)

prefix for 10^-6

μ (micro)