A1-22: HOURGLASS
- ID Code: A1-22
- Purpose: Show an hourglass
- Description:
An hourglass was an early means of time measurement. The picture above shows our elementary version of the hourglass; many historical designs were more sophisticated and thereby able to time such diverse events as boiling an egg or measuring a one hour interval.
This is primarily useful for introducing the concept of mesaurable time units, not for actually making measurements.
- Availability: Available
- References: http://lecdem.physics.umd.edu/images/refs/refsa.htm#A1-22
- Loc codes: A2