1. Measurement + Units

2. Measurements in Physics The most important measurements in Physics are Length, mass and time To make sure everybody in the world can understand each other we all use the same units called SI units (Systeme Internationale)

3. SI units + Symbols QuantitySI UnitSymbolOther Units used Length Mass Time Area Volume

4. SI units + Symbols QuantitySI UnitSymbolOther Units used LengthMetremkm, cm, mm, MassKilogramKgGram (g) TimeSecondSminute (min) Hour (h) AreaSquare metre m2m2 cm 2, km 2 VolumeCubic metre m3m3 cm 3, Litre (L)

5. Measuring lenght A metre stick or ruler measures straight lines

6. Opisometer An opisometer can be used to measure short curved lines for example a road or a river on a map

7. Trundle Wheel Used to measure long curved lengths for example around a flower bed

8. Vernier Callipers To find the diameter or width of a solid object for example marble or a piece of piping Click here to see how it workshere

9. Learning Check What units is length measured in? What units is mass measured in? What units is time measured in? How would you find the length of a short curved line? How would you find the distance from here to the shop?

10. Measuring Area Area is how much space something covers A book has a smaller area than a field To get the area of a regular shape (a square or a rectangle) multiply the length by the width Remember Area = L X W Area is measured in metres squared m 2 (or cm 2, km 2 or mm 2 )

11. Measuring the area of an irregular object Your hand or a leaf does not have a regular shape To get the area of an irregular object trace it onto graph paper and count how many squares it covers, each square has an area of 1mm 2

12. Mass Mass is the amount of matter in an object It is measured in the lab using an Electronic balance Usually measured in Kg or g

13. Measuring Volume Volume tells you how much space something takes up It is measured in m 3 (or cm 3, ml or litres) For a regular object such as a cardboard box Volume = Length X width X Height

14. Measuring volume of irregularly shaped objects A stone or a potato does not have straight edges, it is irregular We can measure the volume of irregular objects using a graduated cylinder and/or an overflow can