True, false, or confidently wrong?
Familiar claims deserve a second look.
Ten questions, with the answers explained. Try them in your head, then open each answer when you're ready.
Play this quiz →QUESTION 1 / 10
A kilogram of feathers weighs less than a kilogram of steel.
- True
- False
Show answer & explanation+
False
Both have a mass of one kilogram. Feathers take up more space.
QUESTION 2 / 10
Lightning is seen before thunder is heard because light travels faster.
- True
- False
Show answer & explanation+
True
Light travels much faster than sound in air.
QUESTION 3 / 10
Every year divisible by four is a leap year in the Gregorian calendar.
- True
- False
Show answer & explanation+
False
Century years must also be divisible by 400. For example, 1900 was not a leap year.
QUESTION 4 / 10
A light-year is a unit of time.
- True
- False
Show answer & explanation+
False
A light-year is a unit of distance.
QUESTION 5 / 10
Mercury is the only metal that is liquid at 20 degrees Celsius.
- True
- False
Show answer & explanation+
True
Among pure metals at 20 degrees Celsius and ordinary pressure, mercury is liquid.
QUESTION 6 / 10
Sound travels through empty space just like light does.
- True
- False
Show answer & explanation+
False
Sound requires a medium; light can travel through a vacuum.
QUESTION 7 / 10
There are exactly seven sharply separated bands of color in a rainbow.
- True
- False
Show answer & explanation+
False
Rainbow colors blend continuously. Seven is a conventional way to name parts of that spectrum.
QUESTION 8 / 10
At ordinary atmospheric pressure, pure water freezes at about 0 degrees Celsius.
- True
- False
Show answer & explanation+
True
Pure water's freezing point is about 0 degrees Celsius at standard atmospheric pressure.
QUESTION 9 / 10
An ordinary square is also a rectangle.
- True
- False
Show answer & explanation+
True
A square meets the definition of a rectangle, with the additional property of equal sides.
QUESTION 10 / 10
All months have at least 28 days.
- True
- False
Show answer & explanation+
True
Every calendar month has a 28th day, not just February.