A sundial is a type of calendar.
True False
What does an hourglass use to measure time?
an hour of glass
a plate with markings
an object with a straight edge
a thin steam of sand
A system for organizing the days of the year by month is called a calendar.
True False
What is the main subject of this article?
the different devices that measure time
how time can move backward
what time is and how it is measured
the history of time measurement
We know when the first calendar was developed
True False
Which of the following is not mentioned as a possible explanation of how time works?
the theory of general relativity
the second law of thermodynamics
the expansion of the universe
movement of matter in our universe