STANDARDS

NGSS: Core Idea: PS1.A

CCSS: Reading Informational Text: 1

TEKS: 6.5A, 6.6A, 7.6A, 7.5B, 8.5A, 8.5C, 8.5D

Cell Phone Chemistry

A look at the elements that make up your smartphone

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

AS YOU READ, THINK ABOUT which elements are used in a cell phone and why.

A typical cell phone contains some of the most valuable elements on Earth. With everything from gold to silver, it’s like having a little treasure chest in your pocket.

A smartphone is packed with at least 40 elements, says Andy Brunning, a chemistry teacher in Bournemouth, U.K. His website, Compound Interest, illustrates the chemistry of everyday items, like phones. People have chemistry to thank for all the things cell phones help us do every day.

Check out the diagram to find out about some of the elements and compounds that put the smarts in your phone.

An everyday cell phone contains some of the most valuable elements on Earth. It has everything from gold to silver. That’s like having a little treasure chest in your pocket.

A smartphone holds at least 40 elements, says Andy Brunning. He’s a chemistry teacher in Bournemouth, U.K. He runs a website called Compound Interest. It shows the chemistry of everyday items, like phones. People have chemistry to thank for all the things cell phones help us do every day.

Check out the elements and compounds in the diagram. You’ll find out how they put the smarts in your phone.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

BATTERY

When you turn on your phone, positively charged lithium ions (atoms that have gained or lost electrons) move through a lithium-salt solution that conducts electricity. Electrons flow out of the battery, producing the electric current that powers your phone. The rechargeable battery’s casing is made of aluminum.

Turn on your phone, and positively charged lithium ions (atoms that have gained or lost electrons) begin to move. They travel through a lithium-salt solution that conducts electricity. Electrons flow from the battery. This produces the electric current that powers your phone. The rechargeable battery’s casing is made of aluminum.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

CIRCUITRY

The circuit board has copper, gold, and silver—good electrical conductors. The connectors (pins that join circuits to the circuit board) are coated in gold because it’s highly resistant to corrosion. The wiring is copper. Solder—an alloy of tin, silver, and copper—binds parts of the circuit board.

The circuit board has gold, copper, and silver. These elements are good electrical conductors. Connectors join circuits to the circuit board. These pins are coated in gold because it strongly resists corrosion. The wiring is copper. Solder is an alloy of tin, silver, and copper. It binds parts of the circuit board.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

COMPUTER CHIP

The chip is the phone’s brain. It has many transistors made of antimony, phosphorus, and gallium arsenide (GaAs). Transistors act as paths and switches that tell the phone to follow or stop following commands. The chip is embedded with silicon—which has low conductivity—to channel electricity only through the conductive transistors.

The chip is the phone’s brain. It has many transistors made of antimony, phosphorus, and gallium arsenide (GaAs). Transistors act as paths and switches. They tell the phone to follow or stop following commands. The chip is made from silicon, an element that is less conductive. That way, it directs electricity only through the conductive transistors.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

TOUCH SCREEN

A thin layer of indium tin oxide—a mixture of indium oxide (In2O3) and tin oxide (SnO2)—conducts electricity. When you touch the screen, a change in the electrical field occurs and communicates your finger’s location to the phone’s chip.

A thin layer conducts electricity. It’s made of indium tin oxide—a mixture of indium oxide (In2O3) and tin oxide (SnO2). When you touch the screen, the electrical field changes. This tells the phone’s chip where your finger is.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

GLASS

Smartphone screens contain aluminosilicate glass, made from the compounds alumina (Al2O3) and silica (SiO2). If you’ve ever dropped your phone and its screen has stayed intact, you can thank potassium ions. They help strengthen the glass by fitting within gaps between other molecules in the glass.

Smartphone screens contain aluminosilicate glass. It’s made from the compounds alumina (Al2O3) and silica (SiO2). Have you ever dropped your phone? If its screen didn’t break, you can thank potassium ions. They help strengthen the glass. The ions do this by fitting within gaps between other molecules in the glass.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

DISPLAY

A cell phone’s display contains several rare earth elements. These elements are spread out widely in Earth’s crust, making them hard to mine. Small quantities of yttrium, europium, and dysprosium help produce the colors on the phone’s liquid crystal display (LCD) screen. Gadolinium, lanthanum, and terbium give the screen its glow.

A cell phone’s display contains several rare earth elements. These elements are spread out widely in Earth’s crust, so they’re hard to mine. The phone’s liquid crystal display (LCD) screen holds small amounts of yttrium, europium, and dysprosium. They help produce the colors on the screen. Gadolinium, lanthanum, and terbium make the screen glow.

MAGICTORCH (ILLUSTRATION); SHUTTERSTOCK.COM (BACKGROUND)

MICROPHONE AND SPEAKERS

The microphone’s wafer-thin diaphragm, which vibrates when sound waves strike it, is made of nickel. The vibrations are converted into an electrical current that becomes the audio signal. Magnets vibrate in the speaker to create audible sound. Neodymium magnets (Nd2Fe14B) are used because they’re the strongest permanent magnets, so even though they’re small, they’re powerful.

The microphone’s extremely thin diaphragm is made of nickel. It vibrates when sound waves strike it. The vibrations are changed into an electrical current that becomes the audio signal.

Magnets vibrate in the speaker. This creates sound we can hear. Neodymium magnets (Nd2Fe14B) are used because they’re the strongest magnets. So even though they’re small, they’re powerful.

OBTAINING INFORMATION: Choose three elements mentioned in the text and explain their function in a cell phone.

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