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237

magnetometer

OLogy Series
tool
card
237

magnetometer

OLogy Series
tool

A magnetometer lets archeologists measure magnetic strengths and detect buried artifacts without digging and destroying a site. It gives them a better idea of where to dig. The Earth acts like an enormous magnet, with north and south magnetic poles. Buried objects can also have a magnetic field. This instrument can detect the magetic fields that buried objects produce.

When archeologists use magnetometers, they take hundreds of readings. The shape of these magnetic variations can reveal:

what an object is made of

what color an object is

the age of an artifact

Are you right?

Correct!

A magnetometer can reveal what an object is made of, and how much iron the object has inside of it.

The Earth's natural magnetic field explains why:

most beaches have a high tide twice a day

a compass needle will always point north

days are longer in the summer

Are you right?

Correct!

The Earth's natural magnetic field explains why a compass needle will always point north, no matter where you are. The spinning Earth is like a giant magnet, with two magnetic poles, the North Pole and the South Pole.

Magnetometers can be used to detect shipwrecks.

Fact
or
Fiction
?

Fact

Magnetometer are commonly used by marine archeologists. They can detect steel in a ship, or iron anchors and cannons.

An archaeologist's eyeglasses can interfere with a magnetometer’s reading.

Fact
or
Fiction
?

Fact

A magnetometer is very sensitive to tiny magnetic differences. It can detect underground rocks, power lines, electrical storms, belt buckles, and even watches.

Definition: an instrument used to measure magnetic variations and detect buried objects
Parts: sensor, data storage unit, cable, power supply
Units of measurement: magnetic field strength measured in gammas
Cool fact: Magnetometers cannot detect bronze or silver.

Image credits: AMNH, David Hurst Thomas.