Understanding the Concept of a Second

Why does the length of a second seem arbitrary?

• Because it is the same as a minute.

• Because it is based on natural events.

• Because it was randomly chosen by scientists.

• Because it is a human-created measurement.

Which ancient civilization is credited with creating the 24-hour day?

• The Ancient Egyptians

• The Romans

• The Babylonians

• The Greeks

Why was the number 60 significant to the Babylonians?

• It was easily divisible by many numbers.

• It was the number of days in their calendar.

• It was the number of gods they worshipped.

• It was the number of stars they could see.

What is the modern scientific definition of a second based on?

• The rotation of the Earth.

• The orbit of the Moon.

• The radiation of the cesium 133 atom.

• The movement of the Sun.

What remains a mystery about the concept of a second?

• How it was first measured.

• How it is defined scientifically.

• How it became part of modern society.

• How it was used in ancient times.