1. Chapter 2 - Introduction to instruments and units used

2. 1. Observation is a science process skill used in investigations 2. Observations Qualitative Quantitative 3. Qualitative observations -5 senses -descriptions e.g. It is smooth. The gas is pungent and colourless. It is moving quickly. 4. Quantitative observation -accurate measurements using instruments e.g metre rule, measuring tape, vernier calipers, measuring cylinder, pipette, burette, electronic balance, spring balance

3. 1. A physical quantity is a quantity which can be measured. e.g. length, area, volume, time, temperature, mass 2. A non-physical quantity is one which cannot be measured. e.g beauty, kindness, humour, sadness, untidiness Physical Quantities

4. Exploring Science 1- CDIS

5. Physical Quantity SI Unit Symbol length metre metre m time second s mass kilogram kg weight newton N

6. Measuring Length 1 m = 100 1 cm = _____ mm 10 1 cm = 1 cm = m = = 0.01 m SI unit: metre (m) Smaller units: millimetre (mm) and centimetre (cm) 1 100 cm 1 m = 1000mm 1 mm = 1 1000 m

7. -metre rule and measuring tape -accuracy of 0.1 cm (1 mm) Instruments for Length

8. External Caliper - accuracy of 0.1 cm Instruments for Length Internal Caliper - accuracy of 0.1 cm

9. External Calipers Measuring the external diameter of a beaker

10. External Calipers Measuring the external diameter of a beaker

11. Internal Calipers Measuring the internal diameter of a beaker

12. Internal Calipers Measuring the internal diameter of a beaker

13. -for measuring short lengths -accuracy of 0.01 cm or 0.1mm Vernier Calipers

14. Physics - A Course for ‘O’ Level Federal

15. Physics - A Course for ‘O’ Level Federal

16. is an error in a measurement due to the eye not being in the correct position when taking a reading. For accurate measurements using the metre rule or measuring tape, the eye must be placed vertically above the mark being read to prevent parallax error. Parallax Error

17. - accuracy of 0.001 cm Micrometer Screw Gauge

18. anvil ratchet frame spindle sleeve thimble Micrometer Screw Gauge

19. - placing the eye vertically above the marking on the scale to be read. - placing a thick ruler on its edge beside the object to be measured so that the scale is touching it - using a thin ruler so that the scale is touching the object to be measured When using a ruler, parallax errors can be avoided by