38 Earth
Earth science is the study of our planet’s physical
characteristics, from earthquakes to raindrops, and floods
to fossils. It contains many branches, such as. GEOLOGY
and oceanography (the study of the world’s oceans).
HOW DO GEOLOGISTS DATE ROCKS?
Rocks are dated using several methods. Geologists
called stratigraphers study the distribution and order
of rock layers, or strata. The youngest rocks are
usually found in layers near the surface; older rocks
lie deeper below. Some rocks contain radioactive
elements that can be dated because they decay,
or change, at a particular rate.HOW DO FOSSILS HELP TO DATE ROCKS?
Fossils (remains or prints of living things preserved
in certain types of rock) tell scientists the relative age
of that rock – that is, whether it is older or younger
than other rocks. This helps scientists to work out the
history of rock formation in different areas. The first
fossils were formed around 3,600 million years ago.WHY IS EARTH SCIENCE USEFUL?
Earth science affects our everyday lives. For example,
meteorologists study the weather and watch for
dangerous storms. Hydrologists study water and
warn of floods. Seismologists study earthquakes
and try to predict where they will strike. Geologists
study rocks and help to locate useful minerals.HOW DO EARTH SCIENTISTS WORK?
Earth scientists mainly work “in the field” – climbing
mountains, exploring the sea bed, crawling through
caves, or wading in swamps. They measure and collect
samples (such as rocks or river water), then they
record their findings on charts and maps.Geology is the study of the rocks that form the planet’s surface.
Geologists examine rocks to find out about the history of the
Earth and how the Earth was formed.GEOLOGY
4 EARTH SCIENCE FROM SPACE
The TOPEX/Poseidon satellite
circles the Earth 1,300 km
(800 miles) above the Earth’s
surface. It uses special sensing
equipment to collect information
about the oceans, which it then
sends back to scientists on Earth.Earth Sciences
EXTREME CONDITIONS 3
Volcanologists study volcanic
eruptions at close quarters,
wearing tough suits and
helmets to protect them from
the heat and deadly fumes.1 DRAGONFLY FOSSIL
Most fossils are of small, shelled
sea creatures. Fossils of mammals
and insects, such as this
dragonfly, are much rarer.FIND OUT MORE. Earthquakes 43 • Fossils 76 • Nuclear Energy 167 • Rocks 46–47
Earth
sciences