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IYPT Elements

IYPT 2019 Elements 031: Gallium: Reading discs and powering the Mars Rover

Element 31 in our International Year of the Periodic Table series is gallium. Gallium is a low melting point metal; combined with arsenic it is used in some types of solar cells, and it’s also a key component of the lasers that read from Blu-ray discs.

Though it’s solid at room temperature, gallium’s melting point is only just above it at 29.8 ˚C. This means that just holding it in your hand is enough to slowly melt it. Gallium is the metal that the spoon in the infamous disappearing spoon trick is made from.

Gallium arsenide is used in some types of solar cells. Specifically, it was used in the solar cells powering the Mars Rover. These cells were stacked in three layers to allow them to absorb more sunlight.

In terms of everyday uses, if you own a device that can play Blu-ray discs, a gallium nitride laser will be being used by the device to read the disc. Meanwhile, gallium nitride LEDs are used to backlight many TV, laptop and phone displays.

Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.