SYLLABUS – Chapter 7
Topic: / Objectives: Students -7. Heat, Light and Sound: Heat, light and sound as forms of energy:
Heat: Sources of heat; transmission of heat, conduction and insulation, convection, radiation.
Effects of heat: thermal expansion of solids, liquids and gases; review changes of state (Topic 3); Temperature as an effect of heat, simple thermometers (Celsius scale only), simple thermostats.
Light: Sources of light, speed of light; straight line propagation of light, simple shadows, pin-hole camera, scattering and transmission of light.
Reflection of light, the plane mirror (nature of image and path of a ray of light only). / • explain and use correctly the words in italics below.
• are aware of familiar sources of heat; they can list several primary sources of heat and distinguish these from hot objects which act as secondary sources.
• are aware that heat can be transmitted by conduction, convection and radiation and can give several familiar examples and applications of each.
• are aware of (thermal) insulation and can give several familiar examples and applications.
• know and interpret simple activities to demonstrate and qualitatively compare (i) the conduction of heat in solids and (ii) the insulating properties of various substances.
• know and interpret simple activities to demonstrate convection in liquids and gases.
• are aware that dark coloured and dull surfaces absorb and radiate heat better than bright, shiny surfaces.
• know and interpret simple activities to demonstrate the absorption and radiation of heat by different surfaces.
• know that solids, liquids and gases expand on heating and contract on cooling.
• know and interpret simple activities that demonstrate thermal expansion is solids, liquids and gases.
• are aware of some every day implications and applications of thermal expansion.
• know that temperature is a measure of hotness and is measured in degrees Celsius.
• know the Celsius temperatures for the melting point of ice, the freezing point of water, the boiling point of water and the normal temperature of the human body.
• are aware of the general range of atmospheric temperatures in their own area.
• describe the construction, and explain the working, of mercury-in-glass laboratory and clinical thermometers.
• are aware that other thermometers may work in different ways.
• explain what a thermostat does and list some familiar appliances that use one.
• explain how a bimetallic strip can be used in a thermostat.
• list familiar sources of light.
• know that light travels in straight lines at a speed of 300,000 km per second.
• know that light is scattered from opaque materials, passes through transparent materials, and is partly scattered by translucent materials.
• are aware that we see objects when light emitted or reflected or scattered from them enters our eyes.
• use words and diagrams to explain the formation of simple shadows.
• make a pinhole camera and explain how it works.
• know that light is reflected at plane surfaces and that the angle of reflection equals the angle of incidence and define these angles with reference to the normal.
• use words and diagrams to describe the path of light, and the formation and nature of the image of an object, in a plane mirror.
Topic: / Objectives: Students -
7. Heat, Light and Sound ( continued):
Refraction through glass and water, displacement of image in water; lenses (nature of images and paths of rays of light only), simple uses of convex lens in camera, projector and hand lens, mention only of systems of lenses in microscopes and telescopes.
Dispersion and the spectrum of white light, making and combining a spectrum with prisms, colour and the colour of everyday objects.
The structure of the human eye, role of eye ball, eye muscles, cornea, eye lids and lashes, tear ducts, iris, pupil, ciliary muscles, retina and optic nerve; binocular vision; long and short sight and their correction.
Sound: Sources of sound, sound as vibration, the human larynx as a vibrating source, propagation of sound in air and other media (no treatment of wave characteristics), echoes, speed of sound in air.
Structure of the human ear, its main parts and their role in collecting and transmitting vibrations, the Eustacian tubes and pressure equalisation, the semi-circular canals and balance, binaural hearing.
Description of sound in terms of the frequency and amplitude of vibration in relation to the pitch and volume of the sound; distinction between musical notes and ‘noise’, sound as pollution. / • use the following terms appropriately in relation to light: refraction, lens, concave, convex, principal axis, principal focus or focal point, focal length.
• know that light bends towards the normal on passing from air to a denser medium, and away from the normal on passing from a denser medium to air.
• use words and diagrams to describe the path of a ray of light through a glass block.
• use words and diagrams to explain the displacement of an image in water.
• use a convex lens (i) as a magnifying glass, (ii) to focus an image on a screen and measure its focal length.
• list, and state the characteristics of, the different kinds of images that can be formed by convex and concave lenses, use ray diagrams to illustrate the formation of each kind of image, and (for convex lenses only) give simple examples of corresponding optical devices including magnifying glass, camera and projector.
• are aware that complex systems of lenses are used in microscopes and telescopes.
• use words and diagrams to describe the formation of a spectrum of colours by dispersion through a prism.
• are aware that a rainbow is a naturally formed spectrum.
• list the colours of the rainbow in the correct order.
• list the primary and secondary colours and describe how these combine with reference to the colour triangle.
• explain the colours of everyday objects by reference to colours absorbed and colours scattered.
• draw a front view and a horizontal section through the human eye, labelling the following parts and explaining their functions: eye ball, cornea, eye lids, eye lashes, tear ducts, iris, pupil, lens, ciliary muscles, retina, optic nerve.
• use the following terms appropriately in relation to sight: long sight, short sight, binocular vision.
• use both sentences and diagrams to explain long and short sight and their correction using appropriate lenses.
• are aware how both field of vision and judgement of distance depend on binocular vision.
• know that sound is caused by vibrations and that these need a medium (usually air) for their transmission;
• list various sources of sound, know that humans make sounds by means of vibrations produced in the larynx and point out where the larynx is situated.
• are aware that echoes are reflected sound.
• know the approximate speed of sound in air and describe a simple, approximate, method of measuring this speed.
• know that we hear sound when sound vibrations, transmitted through the air, reach our ears.
• draw a section through the human ear, labelling the following parts and explaining their functions: ear flap (pinna), ear drum, hammer (maleus), anvil (incus), stirup (stapes), oval window, coclea, auditory nerve, Eustacian tube, semi-circular canals.
• know that judging the direction of a sound depends on binaural hearing.
• explain how the pitch of a sound is related to the frequency of a vibration measured in hertz, and its loudness or volume to the amplitude of the vibration measured in decibels.
• make suitable adjustments to vibrating strings or columns of air to control the pitch and volume of the sounds they make.
• explain the difference between musical notes and ‘noise’.
• discuss noise as pollution.
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