Inside a Phone: Why Its Raw Materials Come From Certain Places

Tech Club Notes: Where Does a Phone Come From?

1The tech club at Linden Hill Middle School took apart an old, broken phone to see what is inside. Club member Keiko Brandt sorted the parts on a tray: copper wires and circuit lines, an aluminum frame, a battery that contains lithium and a glass screen. Their advisor, Mr. Dario Quintero, asked the club a new question: why do the raw materials for these parts come from only certain places on Earth?

2Keiko started with copper. Along some coasts, one plate sinks under another at a deep ocean trench. As the sinking plate goes down, rock deep below the edge of the other plate melts and forms magma. Some magma rises and builds a line of volcanoes. Other magma cools slowly underground. As it cools, very hot water carrying dissolved metals moves through cracks in the rock around it. When that water cools, copper minerals are left behind in the cracks. Geologists searched six sites along one mountain coast, and their results are in the table below.

3Aluminum comes from an ore called bauxite. Bauxite forms when rock is weathered very deeply for a long time and rainwater washes most of its minerals away, leaving clay rich in aluminum behind. Lithium for batteries often comes from salty water under salt flats in high, dry basins that have no outlet to the sea. Streams carry small amounts of dissolved lithium into a basin, the water evaporates in the dry air, and over thousands of years the lithium becomes concentrated. The glass screen is made mostly from quartz sand, which waves, rivers and wind sort and pile up on beaches, in riverbeds and in dunes.

4Last, Keiko found records from a copper mine that has been dug for 40 years. The percent of copper in the rock is called the ore grade. To get copper, a mine digs up rock, crushes it and separates the copper from the waste rock.