iSCIENCE & iMATHS
FROM THE G
REEK...
T
HERMOS + M
ETRON = HO
T + M E A SU R
THERMOS +
E = THERMO
DYNAMIS =
M E T ER
HOT + POWE
R = THERMO
DYNAMIC
GOING HOT AND COLD!
Galileo Galilei, the famous Italian mathematician and astronomer, invented
the thermoscope in around 1600. It measured temperature changes only but
led to modern thermodynamic thermometers with which we 'read' the size
of a liquid (or solid) at different temperatures using a precise number scale.
Forehead strips and digital thermometers use much newer technology;
check out iTech, page 12.
'GALILEO
THERMOMETER'
Invented around 1666...but
not by Galileo! It is a waterfilled glass column containing
labelled glass spheres. These
float or sink as temperatures
vary and affect their
buoyancy in the water.
T
THE RED-HOOF
GREAT FIRE S
LONDON WA 6!
ALSO IN 166
MERCURY
THERMOMETER
In 1714, Polish-Dutch physicist
Daniel Fahrenheit created
the mercury thermometer.
Mercury is an unusual,
metallic, chemical element
that is liquid at room
temperature! It expands as
it warms, then shrinks in
the cold. –Perfect in a glass
thermometer tube and for
measuring many times over.
SCALES
To record temperature as a number, we
need an accurate measuring scale that
can be copied.
Fahrenheit set out his temperature scale in
1724 in which a freezing water mix is 0o F.
Swedish scientist Anders Celsius
published his Celsius (Centigrade) scale
in 1742. In this, pure water freezes at 0o
Celsius, C, and boils at 100o C.
In 1848, Irish physicist William Lord
Kelvin described the Kelvin scale.
It builds from 'absolute zero', which is
the lowest possible temperature.
6
FUSE
(SINCE 2000, MANY
COUN
HAVE BANNED MERCU TRIES
RY AS IT
IS SO POISONOUS.)
NON-MERCURY
THERMOMETERS
Coloured alcohols and the
liquid alloy gallinstan are
alternatives to mercury,
however the modern
replacement tends to
be electronic digital
thermometer technology.