Digital clocks give the time in numbers so we don’t need to read them from a dial. But the numbers still represent hours and minutes, not decimal values. To find the decimal equivalent of hours and minutes you need to use the fact that there are 60 seconds in a minute and 60 minutes in an hour. Each minute is 1/60 = 0.0167 hours, and each second is 1/60 = 0.0167 minutes and (1/60)/60 = 1/3600 = 0.000277 hours. A prime example of when this is necessary is when you have a speed in miles per hour, and a time given in hours, minutes and seconds.
A Matter of Speed
Time in decimals is not the same thing as decimal time. Decimal time is an alternative to the way we measure time in seconds, minutes and hours. You can read about it in the resource.
Determine the number of hours and minutes you want to convert; for example, 3 hours, 17 minutes and 42 seconds.
Divide the number of minutes by 60 to get 0.2833 hours.
Divide the number of seconds by 3600 to get 0.0117 hours.
Add up all the hours to get 3 + 0.2833 + 0.0117 = 3.295 hours.
Calculate the number of miles traveled at 100 miles per hour for 3 hours, 17 minutes and 42 seconds. Using distance = speed_time, the distance traveled is 100_3.295 = 329.5 miles.
- Time in decimals is not the same thing as decimal time. Decimal time is an alternative to the way we measure time in seconds, minutes and hours. You can read about it in the resource.
About the Author
Ariel Balter started out writing, editing and typesetting, changed gears for a stint in the building trades, then returned to school and earned a PhD in physics. Since that time, Balter has been a professional scientist and teacher. He has a vast area of expertise including cooking, organic gardening, green living, green building trades and many areas of science and technology.