Page 83 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

Science

How do Bunsen burners work?

Find out how its flame reaches temperatures of up to 1,200°C
obert Bunsen invented the Bunsen
burner in the mid-19th century as
R a means to an end. The German
chemist’s work focused on emission
spectra, which is the bright light produced
by different elements when they are

heated in a flame. To carry out this
experiment he required a hot, clean fl ame,
which gave him the idea for the Bunsen
burner. A modern Bunsen burner consists
of a straight metal tube, measuring about
13 centimetres (five inches) long, attached

to a base stand. A thin rubber tube known
as a gas hose connects to the bottom and
supplies gas to the Bunsen. The metal
collar works to adjust the amount of air
that enters the tube by altering the size of
the air hole at the base. By allowing air and
therefore oxygen to mix with the gas, a
hotter and more complete reaction occurs,

causing a very hot, blue flame to be
produced. The Bunsen still has an
Bunsen burners are typically abundance of laboratory applications
fuelled with natural gas, which today, including sterilisation and fi xing
is almost pure methane, CH4
cells to microscope slides.

Why does foam form?

Popping the mystery behind this strange substance

oams are made up of thousands of tiny
bubbles and have a wider range of Foam’s structural features
Fapplications than you would expect.

They are used to fi ght fire, separate ores and How foam’s unusual physical
manufacture vehicles; one type has even properties affect its appearance
been used to neutralise anthrax.
Upon handling foam, its physical state is
somewhat unclear. Although it has qualities
of all three states of matter, typical liquid
foam is 95 per cent gas and five per cent

liquid. Foams contain a surfactant, which
prevents the bubbles from immediately
popping by keeping them separate and
repelling water.
Foam is far more rigid than you would
expect, which is due to something known as
jamming. This phenomenon occurs because
the foam bubbles are incredibly tightly
packed, meaning the bubbles can’t move
around each other when they are
compressed. The pressure within the
bubbles will continue to increase as they
are further compressed, making the foam
appear even more solid.
A study into foam optics and mechanics
was conducted on the International Space
Station between 2009 and 2010 in order to
look at foam stability and foam coarsening, © Corbis; Thinkstock
along with how microgravity affects a
liquid’s ‘foamability’.

How It Works 83