Conversions
- As well as prefix (powers of ten) conversions (eg. km into m) there are also common unit conversions
- One such unit conversion are those for time
- The main time conversions are shown in the table below:
Time Conversions Table
Hours & Seconds
- A common time unit conversion is between hours and seconds
- 1 hour = 60 minutes
- 1 minute = 60 seconds
- Therefore 1 hour = 60 × 60 = 3600 seconds
- To convert from hours → seconds, multiply by 3600
- To convert from seconds → hours, divide by 3600
Hours × 3600 = Seconds
Seconds ÷ 3600 = Hours
Kelvin & Degrees Celsius
- A common temperature unit conversion is between Kelvin and degrees Celsius (ºC)
- The scale is defined as: 0 K = -273.15 ºC
- To convert from Kelvin → Celsius, subtract 273.15
- To convert from Celsius → Kelvin, add 273.15
K − 273.15 = oC
oC + 273.15 = K
Worked example
A cyclist takes 3.5 hours to travel to their destination. Calculate their time travelled in seconds.
Step 1: State the conversion
1 hour = 3600 s
Seconds = Hours × 3600
Step 2: Calculate the time in seconds
3.5 × 3600 = 12 600 s
Examiner Tip
You will be expected to remember these unit conversions in your exam and to confidently convert between them, so make to practice these to achieve full marks in the calculation questions.