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The decibel (dB) is named after Alexander Graham Bell, who invented the telephone. The lower limit of human hearing is 0dB, while 100 dB is a jack hammer from one metre away. Kelvin is a measure of temperature, the ohm is a measure of resistance in electricity, and the candela is a measure of brightness.

True. But first, what’s a mineral? A mineral has a specific chemical formula with atoms arranged in a crystal pattern. For example, diamonds are minerals made of carbon atoms arranged in tetrahedrons (like the points of a pyramid). There are more than 6,000 known minerals and about 50–100 new ones are described each year.

The average for Aussie cyclones per year is 11! Most of these occur between November and April and, on average, about 4 out of these 11 come onto land. Worldwide, there is an average of about 80-100 tropical cyclones each year.

Impressively, Babylonian tablets show evidence of fractions, interest rates and some impressively large Pythagorean triples. Some tablets look like graded homework!

A strong password uses uppercase letters, lowercase letters, numbers and symbols (like !, @, #, $). It’s also important to use passwords that are different from past ones. Strong passwords are harder to remember so it is a good idea to use a password manager.

David Unaipon was an Aboriginal inventor. He invented the shearing machine and the centrifugal motor. Mary Reibey was a convict who became a very successful businesswoman and is on the $20 note. Banjo Patterson was a poet and is on the $10 note. Dame Nellie Melba was a soprano and is on the $100 note.

The word pentagram comes from Ancient Greek. Penta- means five and -gram means drawing. A pentagram can be drawn with five straight lines, without lifting your pencil. A hexagram is a six-sided star. A pentagon is a five-sided shape. A rhombus is a four-sided shape whose sides are all equal.

While legend says that the apple fell on poor Isaac’s head, his biographer wrote that he simply saw the fruit falling from a tree. He was “struck” by how the apple fell straight down. He then made the connection between the force that brings the apple down and the force that keeps planets and moons in orbit. Both are gravity!

More than 5,000. In fact, the United Nations lists almost 13,000 artificial satellites in Earth’s orbit! This is quite an increase from 1 artificial satellite, Sputnik, launched in 1957. Although Sputnik is no longer in orbit, the fourth satellite, Vanguard 1, is still up there!

Large hard drives are made of trillions of tiny magnets, and information is stored by pointing them in different directions. Electric motors use electromagnets to push and pull to make things spin. Medical imaging such as Magnetic Resonance Imaging (MRI) uses super powerful magnets and radio waves to construct a detailed picture of your body.