Time

• Time


  An ongoing and continuous sequence of events that occur in succession from the past through the present to the future
• Basic units of time

  • Seconds
  • Minutes
  • Hours
  • Day
  • Week
  • Month
  • Year
• The instrument used to measure time is a clock
• Types of clocks


  • Analog
  • Digital
• Analog clock


  Has numbers from 1 to 12 that tell the hour, and 60 divisions that are used to express the minutes
• Digital clock


  Displays the time in hours and minutes directly, without a minute hand or hour hand
• AM (Ante Meridian)


  The first twelve (12) hours of the day, before midday
• PM (Post Meridian)


  The remaining twelve (12) hours of the day, after midday
• Longer time units


  • Minute
  • Hour
  • Day
  • Week
  • Month
  • Year
  • Decade
  • Century
  • Millennium
• 60 seconds = 1 minute
• 60 minutes = 1 hour
• 24 hours = 1 day
• 7 days = 1 week
• 52 weeks = 1 year
• 365 days = 1 year
• 12 months = 1 year
• Fortnight


  14 days, or 2 weeks
• Addition of Time


  1. Add the hours

  2. Add the minutes, if 60 or more subtract 60 and increase the hour by 1

  3. Repeat if minutes are still 60 or more
• Subtraction of Time


  1. Compare the minutes of both times

  2. If time A minutes are less than time B, take 1 hour away from time A

  3. Subtract the minutes

  4. Subtract the hours
• 12-hour clock system


  • Clock has hour, minute and second hands
  • Hour hand goes around clock once per 12 hours
  • Minute hand goes around clock once per 60 minutes
  • Day split into morning (am) and afternoon (pm)
  • 12 midnight is 12 am, 12 noon is 12 pm
• 24-hour clock system


  • Day goes from midnight to midnight and is divided into 24 hours
  • Indicated by hours passed since midnight from 0 to 23
  • No am/pm labels
• 12-hour clock


  Divides day into 12 hour periods
• 24-hour clock


  Divides day into 24 continuous hours
• Converting 12-hour to 24-hour clock

  1. Add 12 to hours from 1 pm to 11 pm

  2. Change 12 am to 0

  3. Subtract 12 from 1 am to 12 pm