Curriculum
- 25 Sections
- 92 Lessons
- 70 Hours
- 1.1 - Physical quantities and measurement techniques5
- 1.1Use of rulers and measuring cylinders to find a length or a volume
- 1.2Describe how to measure a variety of time intervals using clocks and digital timers
- 1.3Determine an average value for a small distance and for a short interval of time by measuring multiples (including the period of oscillation of a pendulum)
- 1.4Quiz Test 1Copy10 Minutes2 Questions
- 1.5TestCopy
- 1.2 - Motion4
- 1.3 - Mass and weight1
- 1.4 - Density1
- 1.5 - Forces5
- 1.6 - Momentum1
- 1.7 - Energy, work and power5
- 1.8 - Pressure1
- 2.1 - Kinetic particle model of matter5
- 2.2 - Thermal properties and temperature5
- 2.3 - Transfer of thermal energy5
- 3.1 - General properties of waves6
- 3.2 - Light7
- 3.3 - Electromagnetic spectrum2
- 3.4 - Sound3
- 4.1 - Simple phenomenon of magnetism3
- 4.2 - Electrical quantities5
- 4.3 - Electric circuits7
- 18.1Circuit diagram – Circuit components and their functionsCopy
- 18.2Effective or equivalent resistance in series and parallel circuitsCopy
- 18.3Behaviour of series and parallel circuitsCopy
- 18.4Function of LDR (Light Dependent Resistor) and thermistorCopy
- 18.5Potential divider and potentiometerCopy
- 18.6Use of relay in a circuitCopy
- 18.7Diode in half and full wave rectifier bridgeCopy
- 4.4 - Electrical safety2
- 4.5 - Electromagnetic effects6
- 5.1 - The nuclear model of the atom2
- 5.2 - Radioactivity5
- 6.1 - Earth and the Solar System2
- 6.2 - Stars and the Universe3
- Paper 6 instructions3
Basic characteristics of sound wavesCopy
Learning Objectives
- Describe the production of sound by vibrating sources
- Describe the longitudinal nature of sound waves
- State that the approximate range of audible frequencies for a healthy human ear is 20 Hz to 20 000 Hz
- Show an understanding of the term ultrasound
- Show an understanding that a medium is needed to transmit sound waves
- Relate the loudness and pitch of sound waves to amplitude and frequency
- Describe compression and rarefaction
- State typical values of the speed of sound in gases, liquids, and solids
Contents to learn
Nature of sound waves
Sound is a form of energy produced by a vibrating body.
Vibrations of the sounding body may be seen or felt. For example, if a tuning fork is struck by a rubber pad, it will start vibrating.
One can listen to the sound and at the same time, its vibrations can be felt, on touching any of its prongs.
Sound waves are not electromagnetic, they need a medium to travel and it cannot travel through a vacuum.
Experiment: Sound can not travel through the vacuum
An electric bell is suspended from wires passing through the cork in a bell jar with stands on the plate of an air pump.
The bell is set ringing and the air is pumped out of the jar. As the air is removed, the sound becomes fainter until it may become inaudible althoug the bell can still be seen ringing. As the air is readmitted, the sound becomes louder once again. Three things are necessary for the production, propagation, and observing the sound.
1- A vibrating body
2- Some material medium like air and water
3- Receiver like ear
Production of sound
Whenever a body is vibrating, it produces a disturbance in the surrounding air. this disturbance reaches our ear in the form of waves and hence produces sensation on the eardrum. In the absence of air (medium), the sound can not be heard, because sound can not travel through a vacuum. Therefore a material medium must be continuous from the vibrating body to the ear.
Characteristics of sound
- Loudness of sound waves
- Pitch of sound waves
- Quality of sound waves
Audible frequency range
The sound having frequencies between 20 Hz to 20 000 Hz can be heard, this frequency range is called an audible frequency range.
