Hourglass

The hourglass, also known as the sandglass, is a timekeeping instrument that has been used for centuries. The sandglass is constructed using two conic reservoirs that are joined at their apexes by a small hole. One reservoir is filled with a ...

  • Loading...
locked icon

Sign in to access this content

Get a 30 day FREE TRIAL

  • Watch videos from a variety of sources bringing classroom topics to life
  • Read modern, diverse business cases
  • Explore hundreds of books and reference titles