1. Dr J Frost (jfrost@tiffin.kingston.sch.uk)
GCSE: Units
Dr J Frost
GCSE Revision Pack Ref: 157, 158, 160
Last modified: 13th April 2015

2. GCSE Specification
(Using revision pack reference numbers)
157. Convert between units of measure in the same system. (NB: Conversion between imperial units will be given, metric equivalents should be known.)
158. Know rough metric equivalents of pounds, feet, miles, pints and gallons: Metric/Imperial
Convert between imperial and metric measures
160. Convert between metric units of speed eg km/h to m/s

3. 1 m = 100 cm 1cm = 10 mm 1 ton = 1000 kg 1 kg = 1000 g 1 𝑙 = 1000 ml
Metric ↔ Metric Conversions
1 m = 100 cm
1cm = 10 mm
1 ton = 1000 kg
1 kg = 1000 g
1 𝑙 = 1000 ml
1 𝑙 = 1000 cm3 ? ? ? ? ? ?

4. Imperial & Metric Metric Imperial Length Mass Capacity Feet Tonnes
Litres
Gallons
Metres
Pints
Inches
Miles
Pounds kg
Miles
Stone
Metric
Imperial
Length
Mass
Capacity

5. Metric ↔ Imperial Conversions
You need to memorise these for your GCSE exam!
1 kg ≈ pounds (≈ means ‘approximately equal to’)
1 litre ≈ pints
4.5 litres ≈ gallon
8 km ≈ miles
30cm ≈ foot ? ? ? ? ?
Test Your Understanding
5.4kg = pounds
49.69 pints = litres
40km = miles
75cm = foot ?
30 miles = km
28km = miles
480 miles = km ? ? ? ? ? ?

6. Memorise Time! ? ? ? ? ? ? ? ? ? ? 1 kg ≈ 2.2 pounds
1 litre ≈ pints
4.5 litres ≈ gallon
8 km ≈ miles
1 foot ≈ cm ? ? ? ? ?
4.5 litres ≈ gallon
1 litre ≈ pints
8 km ≈ miles
1 foot ≈ cm
1 kg ≈ pounds ? ? ? ? ?

7. Converting between compound units
30m/s
65m/s
 1000 ?
0.03 km/s ?
× 3600 ?
108 km/h
234 km/h ? ?

8. Test Your Understanding
175 m/s
45km/h
630 km/h
12.5 m/s ? ?

9. Exercises
The radius of the Earth is 6371km
How many miles is that? 3982 miles
London and Auckland are at exact opposites of the Earth. If I fly at 450mph, how many hours will it take to get there? 27.8 hours
Usain Bolt can run m/s. What is that in:
km/h? km/h
mph? mph
Pippin the cat weighs 9.2 pounds. I want to enter Pippin along with cats of the same weight into Crufts. My total weight limits is 1 ton of cat. How many cats can I take?
239 cats
Convert the following:
650 km/h → m/s
1 m/s → km/h 1 5
[Edexcel] Emily is driving in France. She sees this sign. Emily is going to drive to Dijon. She plans to drive at an average speed of 50 miles per hour. Work out how long it should take Emily to drive to Dijon.
To experiment to see if cats land on their feet, I release Pippin upside down at the top of a 6000 foot drop. What is that in km?
1.8km
The average human consumes about 7.6 pints of cow’s milk a day. How many litres is that in a year? litres
If my Ferrari consumes 6 gallons of petrol each hour and my Aston 8 gallons each hour, what is the difference in time in seconds, between the two cars, to consume a litre of petrol? 33.3 seconds ? ? 2 ?
6 hours ? ? 6 3 ? 7 ? ? 4 8 ? ? ?