Physics form 4 chapter1 slides
- 1. Chapter 1: Introduction to Physics Form 4 1 Physics Next > The study of matter
- 2. Objectives: ( what you will learn ) 1) understand Physics 2) base quantities & derived quantities 3) scalar quantities & vector quantities 4) measurements , using instruments 5) processes in scientific investigations Physics: Chapter 1 2 < Back Next >
- 3. Understanding Physics: Physics 3 1. “Physics” derives from Latin, “ physica” - the science of natural things; until 19 th century, it was called “ natural philosophy ”. Through its subfield of astronomy , it may be the oldest academic discipline. 2. Physics is a branch of Science for study of natural phenomena , which involves force, matter & energy; based on experimental observations & quantitative measurements. < Back Next >
- 4. Base Quantities Physical Quantities 4 Quantities that cannot be defined in any other physical quantity. < Back Next > Ampere Kelvin second kilogram meter SI Unit Current Temperature Time Mass Length Base Quantity A I K T s t kg m m l Symbol Symbol
- 5. Derived Quantities 5 Physical Quantities Quantities derived from base quantities (through mathematical combinations). Volume = Length x Breath x Height = m 3 Density = Mass ÷ Volume = kg m -3 Velocity = Displacement ÷ Time = m s -1 Acceleration = Velocity ÷ Time = m s -2 Force = Mass x Acceleration = kg m s -2 < Back Next >
- 6. 6 Physical Quantities Scalar Quantity Physical quantity which has magnitude only, such as distance and mass. ( Compare them to base quantities .) Vector Quantity Physical quantity which has both magnitude and direction , such as force and pressure. ( Compare them to derived quantities .) < Back Next >
- 7. 7 Physical Quantities Prefixes Simplifies description of physical quantities that are either very big or very small without losing data. < Back Next > c m µ n p symbol centi milli micro nana pico prefix 10 -2 10 -3 10 -6 10 -9 10 -12 value 10 3 k kilo 10 6 M mega 10 9 G giga T symbol tera prefix 10 12 value 1 Small quantities Big quantities
- 8. 8 Physical Quantities Scientific Notation The standard form for numerical magnitude. Q x 10 n where 1 ≤ Q < 10 and n is an integer Examples : 0.000000696 m = 6.96 x 10 -7 m 911 000 000 kg = 9.11 x 10 8 kg < Back Next >
- 9. 9 Measurements Accuracy measures how close a hit is to the target. If it is too far from the target, it is not accurate. Consistency measures how close together a group of hits is to the average value. If they are far apart from each other, they are not consistent. We want results that are both accurate & consistent. < Back Next > Consistent, less accurate Accurate, less consistent Not accurate, not consistent Accurate & consistent
- 10. 10 Measuring Instruments Sensitivity = how small a change in reading that can be measured by an instrument < Back Next > Ruler Low, 1 mm Vernier caliper Medium, 0.1 mm Micrometer screw gauge High, 0.01 mm
- 11. 11 Measurement Errors Incorrect calibration of instruments Systematic Error Occurs in one direction only. Zero error – pointer of instrument does not return to zero when not in use, such as a ruler worn out at one end Repeated error in reaction time Wrong assumption too low too high Always negative Always positive May arise from various causes. or < Back Next >
- 12. 12 Measurement Errors Random Error Size of error not constant & unpredictable . The reading is sometimes positive & sometimes negative from actual value. < Back Next > May arise from various causes. Parallax error – due to incorrect positioning of the eye when taking measurement Changes in the surroundings; i.e. temperature, air circulation, lighting, magnetic field, etc. Can be reduced in several ways. Repeated measurements – taking mean value Using mirror beneath pointer of instrument
- 13. 13 Scientific Investigation The processes involved < Back Next > Making use of all human senses Initial explanation or conclusion Making smart guesses Testing in controlled situation Documentation of results in report Start End Observation Inference Hypothesis Experiment Conclusion
- 14. 14 Scientific Experiment Steps involved in carrying out Experiment < Back Next > Aim Variables Apparatus Procedures Tabulation Analysis Suggest suitable questions Manipulated, responding, & fixed List apparatus/materials, arrangement Carry out experiment in proper order Documenting data obtained Analyze data through graphs, etc.
- 15. 15 Summary < Back What you have learned: Understanding Physics Physical Quantities Thank You 3. Measurements & Instruments 4. Scientific Investigations & Experiments
Editor's Notes
- #11: Links: http://en.wikipedia.org/wiki/Ruler http://www.notesandsketches.co.uk/Measuring-marking-out.htm http://en.wikipedia.org/wiki/Calipers http://en.wikipedia.org/wiki/Micrometer