Units & Measurement Trivia: Light-Years, the Metric System, and Classic Misconceptions

64 questions · by Quizbun

Sixty-four questions on the units we measure the world with — and the famous mistakes people make about them. Six parts: cosmic distances (why a light-year is a distance and not a time, what a parsec and an astronomical unit really are), the origin of the metric system (revolutionary France, the meridian survey, the original metre and kilogram), SI base units and the 2019 redefinition (the seven base units, the caesium second, and why the kilogram is now the Planck constant), temperature scales (absolute zero, why there is no 'degree Kelvin', and Celsius's upside-down original), classic unit confusions (knots, calories, watts vs watt-hours, carats vs karats, and the $125-million Mars units disaster), and everyday conversions and famous numbers. Many answers are numeric so you practise the figure, not just recognition, and every explanation links to Wikipedia or another source so you can verify it and read further. Several questions deliberately correct a popular but false 'fact'.

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Questions

Not answered. What does a light-year measure?
Not answered. About how many trillion kilometres is one light-year?
Not answered. About how many trillion miles is one light-year?
Not answered. When defining a light-year, the International Astronomical Union uses which kind of 'year'?
Not answered. Roughly how fast does light travel in a vacuum?
Not answered. How long does light from the Sun take to reach the Earth?
Not answered. About how far is one light-second?
Not answered. In Star Wars, Han Solo boasts of making the Kessel Run 'in less than twelve parsecs.' What does a parsec actually measure?
Not answered. About how many light-years is one parsec?
Not answered. Where does the parsec get its name and definition?
Not answered. What is an astronomical unit (AU)?
Not answered. About how many million kilometres is one astronomical unit?
Not answered. Which is the nearest star to the Sun?
Not answered. Why is it wrong to say 'the journey took ten light-years'?
Not answered. In which country did the modern metric system originate?
Not answered. How was the metre originally defined in the 1790s?
Not answered. To fix the metre, surveyors Delambre and Méchain measured the meridian arc between which two cities?
Not answered. The metric system scales its units using which base?
Not answered. How was the original kilogram defined?
Not answered. The word metre comes from which root?
Not answered. In the modern system of units, what does the abbreviation SI stand for?
Not answered. In which year was the modern system formally named the 'Système International d'Unités' (SI)?
Not answered. The US customary units (inches, pounds, gallons) derive mainly from which source?
Not answered. How many base units does the SI define?
Not answered. Which of the following are SI base units?
Not answered. What is the SI base unit of mass?
Not answered. Which SI base unit is unusual because its name already contains a metric prefix?
Not answered. Since 1983, how is the metre officially defined?
Not answered. How is the SI second defined today?
Not answered. Exactly how many oscillations of the caesium-133 atom define one second?
Not answered. In the 2019 overhaul of the SI, the base units were redefined in terms of what?
Not answered. Since 2019, the kilogram is defined using which fundamental constant?
Not answered. The retired International Prototype of the Kilogram — 'Le Grand K' — was made of what?
Not answered. In which year was the physical kilogram prototype retired in favour of a constant-based definition?
Not answered. The mole is the SI base unit for which quantity?
Not answered. Avogadro's number is about how many particles per mole, written as a coefficient times 10^23?
Not answered. What is absolute zero, in degrees Celsius?
Not answered. Which is the correct way to write a temperature of three hundred on the Kelvin scale?
Not answered. At what temperature do the Celsius and Fahrenheit scales read the same number?
Not answered. At standard sea-level pressure, water boils at how many degrees Fahrenheit?
Not answered. Normal human body temperature is conventionally quoted as about how many degrees Fahrenheit?
Not answered. When Anders Celsius first proposed his scale in 1742, how was it arranged?
Not answered. What did Daniel Fahrenheit originally use to set 0 °F?
Not answered. A temperature change of one kelvin equals a change of how much on the Celsius scale?
Not answered. In navigation, what does a knot measure?
Not answered. How does a nautical mile compare with an ordinary (statute) land mile?
Not answered. What is a nautical mile historically based on?
Not answered. The 'Calorie' listed on food nutrition labels is equal to what?
Not answered. Which statement about the watt and the watt-hour is correct?
Not answered. About how many watts is one (mechanical) horsepower?
Not answered. Which statement about the word ton is correct?
Not answered. What is the difference between a carat and a karat?
Not answered. How does an earthquake magnitude scale (Richter / moment magnitude) work?
Not answered. What kind of scale is the decibel?
Not answered. In 1999, NASA lost the $125-million Mars Climate Orbiter. What went wrong?
Not answered. How many feet are there in one (statute) mile?
Not answered. How many metres are there in one kilometre?
Not answered. How many inches are there in one foot?
Not answered. In the British system, how many pounds are there in one stone?
Not answered. The metric prefix giga- means a factor of what?
Not answered. Which of these metric-prefix values are correct?
Not answered. How does a US gallon compare with an imperial (UK) gallon?
Not answered. Which trio of countries is most often cited as not having officially adopted the metric system?
Not answered. One ångström equals what length?