Being a Physicist Unit 5 Summary Sheets Gleniffer High School 0
Experiences & Outcomes I can explain how sound vibrations are carried by waves through air, water and other materials SCN 2-11a By exploring reflections, I can use my knowledge of the properties of light to show how it can be used. SCN 2-11b I have collaborated with others to find and present information on how scientists from Scotland have contributed to innovative research and development. SCN 3-20a By recording and analysing sound signals, I can describe how they can be manipulated and used in sound engineering SCN 4-11a I can explain the use of radiation and discuss how this has impacted upon society and our quality of life. SCN 4-11b 1
I can use my knowledge of different ways in which heat is transferred between hot and cold objects and the thermal conductivity of materials to improve energy efficiency in buildings or other systems. SCN 3-04a By exploring refraction of light when passed through different materials, lenses and prisms, I can explain how light can be used in a variety of applications. SCN 3-11a By exploring radiations beyond the visible, I can describe a selected application, discussing the advantages and limitations. SCN 3-11b 2
Explore the nature of sound, light and radiations in the electromagnetic spectrum. Develop understanding of the properties of light and other forms of electromagnetic radiations. Explore how different waves relate to the environment and how we make use of them in health, medicine and communications. o All waves transfer energy o Sound, light, heat and water are all type of waves o The amplitude of a wave is an indication of the energy in a wave the higher the peak amplitude the greater the energy 3
o The energy of a wave can be measured the method used to measure the energy is different for each type of wave. Water measure the height of the wave and/or flow rate of water Light using a light meter or solar cell Sound using a sound level meter 4
I can explain how sound vibrations are carried by waves through air, water and other materials SCN 2-11a o Sounds are made by objects vibrating o Sounds can travel because particles close to them can vibrate o Solids, liquids and gases all contain particles and so sound can travel through them. o In a string telephone sound vibrations are collected by the cup and carried along the string to the other cup o As it travels, a sound wave will lose energy this explains why we cannot hear sounds from far away sources o A vacuum does not contain particles and so sound cannot travel through a vacuum. 5
I have collaborated with others to find and present information on how scientists from Scotland have contributed to innovative research and development. SCN 3-20a o Frequency is a measure of how many times an object vibrates per second o Frequency is measured in hertz (Hz) o The normal range of hearing for a human is between 20 and 20 thousand hertz - sounds above or below this range are inaudible (you cannot hear them) o Some animal communicate with frequencies above and below the normal range of human hearing o Sounds above 20 thousand hertz are known as ultrasounds o Ultrasound has many medical and industrial uses for example scanning unborn babies or sonar which is often used to find objects under the sea 6
o You should be able to state at least one medical and one non-medical use for ultrasounds * * k or kilo before a variable means that there are thousand of that variable e.g. khz (kilohertz) means 1000 hertz and so 2kHz means 2000 hertz 7
By recording and analysing sound signals, I can describe how they can be manipulated and used in sound engineering SCN 4-11a o Amplifiers are used to make sounds louder by increasing the energy of the sound wave o An amplified wave will have a higher amplitude (showing that it has more energy) but will have the same frequency o Interference of two or more sounds can also change the shape of a sound wave 8
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I can explain the use of radiation and discuss how this has impacted upon society and our quality of life. SCN 4-11b o The electromagnetic (EM) spectrum contains different types of waves o EM spectrum waves do not need particles to transfer energy and so can travel through a vacuum o All waves in the EM spectrum travel at the speed of light - 300 million metres per second faster than sound at 340 metres per second o Only visible light is visible in the EM spectrum o The EM spectrum is made up of: Radio and TV Wave Microwaves Infra-red Visible light Ultraviolet X-rays Gamma rays 10
I can use my knowledge of different ways in which heat is transferred between hot and cold objects and the thermal conductivity of materials to improve energy efficiency in buildings or other systems. SCN 3-04a o Heat is a form of energy o Temperature is a measure of how hot or cold something is o Heat can come from natural sources such as the sun or living things o Heat can come from artificial sources such as fires and heaters 11
By exploring radiations beyond the visible, I can describe a selected application, discussing the advantages and limitations. SCN 3-11b 12
By exploring radiations beyond the visible, I can describe a selected application, discussing the advantages and limitations. SCN 3-11b Conduction o Metals are good conductors of heat o The ability of a metal to conduct heat is known as thermal conductivity o Heat is transferred through a conductor as energy is passed from one particle to another o Some metals are better at conducting heat than others o A comparison of the thermal conductivity of different metals can be made using conductivity bars or a conductivity ring 13
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Cooling Down o Hot objects will release heat to cold objects o Heat loss can be measured by observing a change in the temperature of a hot object over time o Cooling curves drawn from experimental results can be used to compare heat loss through different materials A fastest rate of heat loss Temp. C B cooling down more slowly C cooling but starting to level out time D temperature the same as room temperature 15
Convection o Heat travels through a fluid by convection o In convection particles become less dense as they are heated and rise in the liquid, as they rise colder particles sink o The movement of particles through a fluid as it is heated is known as a convection current o A convection current always starts upwards from a heat source This is how a radiator works in your house! This is how the radiator in your house works! 16
o Heat cannot travel through a vacuum by conduction or convection as there are no particles o Heat travels through a vacuum by radiation o Matt, black surfaces are the best at absorbing and emitting heat o Shiny, silver surfaces are the best at reflecting heat 17
I can use my knowledge of different ways in which heat is transferred between hot and cold objects and the thermal conductivity of materials to improve energy efficiency in buildings or other systems SCN 3-04 o Heat is lost in homes through conduction, convection and radiation o There are many methods of reducing heat loss in the home such as: insulation, carpeting and double glazing o Can you state at least two methods for reducing heat loss in the home and explain how they function. 18
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By exploring reflections, I can use my knowledge of the properties of light to show how it can be used. SCN 2-11b o Light is a wave o Light is reflected from a mirrored surface Reflection Plane Mirror The angle of reflection for light (r) on a plane mirror is equal to the angle of incidence (i). Curved Reflectors. A concave mirror will reflect light to a focus point in front of the mirror. A convex mirror will cause the light to spread out. 20
By exploring refraction of light when passed through different materials, lenses and prisms, I can explain how light can be used in a variety of applications. SCN 3-11a Refraction o Refraction is the change in speed of light when moving from one material to another o Light entering glass or plastic from air will slow down as glass is a more dense material o Refraction can cause the direction of light to change when moving from one material to another Refraction through lenses 21
Light through a prism o When monochromatic light (light of one colour) goes through a prism it refracts o When white light goes through a prism it produces a spectrum of all the colours of visible light Red, Orange, Yellow, Green, Blue, Indigo and Violet (ROYGBIV) 22
Normal Sight The cornea a protective layer over the front of the eye The iris changes size when light levels change The pupil a hole that allows light to enter the eye The lens helps focus rays of light onto the retina Muscles used to move the eyeball Retina - a screen containing light sensitive cells. Changes light energy into electrical energy Optic nerve carries electrical signals from the retina to the brain 23
Sight Defects o Short-sightedness means we can only see close objects clearly it is due to light focusing before the retina (caused by elongation of the eyeball) o Long-sightedness means that we can only see far away objects clearly it is due to light focusing after the retina (caused by thinning of the lens or lack of control in the eye muscles) o Concave lenses can be used to treat short sight o Convex lenses can be used to treat long sight 24
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