Light and sound
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Transcript of Light and sound
Autora: Marta García T.
Light is a kind of electromagnetic energy, formed by very small particles called photons.
The light which allows us to see is called Visible Light.
Autora: Marta García T.
Autora: Marta García T.
Objects can be transparent, translucent or opaque, depending on how light travels through them:
Transparent: they allow light to travel through. Opaque: they absorb or reflect most of the light
they receive, so they don’t allow light to travel through.
Translucent: they absorb some light, and allow some to travel through.
Autora: Marta García T.
Shadows are places where light is “blocked”:
Rays of light
Autora: Marta García T.
1) Light travels in straight lines:
2) Light travels very fast, about 300.000 Km/s in the vacuum.
Laser
Autora: Marta García T.
3) Light Reflection: we see things because they reflect light into our eyes.When a ray of light hits a surface, it bounces off, and begins to travel in a different direction.
Autora: Marta García T.
Autora: Marta García T.
Incident ray
Normal
Reflected ray
Angle of incidence
Angle of reflection
Mirror
Autora: Marta García T.
Smooth, shiny surfaces have a clear reflection
• Rough, dull surfaces have a diffuse reflection.
Autora: Marta García T.
4) Light Refraction: light is refracted when it passes from one medium to another which has a different density. Light bends at the boundary between the two media.
Ex. Water is denser than air.
Autora: Marta García T.
Lenses are discs made of glass or plastic with one or two curved faces. They refract light. There are two types:
Converging Lenses: they concentrate the rays of light.
Diverging Lenses: they disperse the rays of light.
http://recursostic.educacion.es/newton/web/materiales_didacticos/optica/opt33.htm?2&2Autora: Marta García T.
White light is not a single colour; it is made up of a mixture of the seven colours of the rainbow.
We can demonstrate this by splitting white light with a prism
This is how rainbows are formed: sunlight is “split up” by raindrops.
Autora: Marta García T.
Autora: Marta García T.
The colour of an object depends on the colours of light it reflects.
Ex. A red book only reflects red light:
White
light
Only red light is reflected
Autora: Marta García T.
Autora: Marta García T.
Autora: Marta García T.
Autora: Marta García T.
Autora: Marta García T.
Sound is a form of mechanical energy produced by the vibration of an object.
It travels in waves, and its speed depends on the medium.
In the air: 340 m/s. In water: 1,5 m/s.
http://www.juntadeandalucia.es/averroes/recursos_informaticos/andared01/paisaje_sonoro/sonido.htmhttp://www.juntadeandalucia.es/averroes/recursos_informaticos/andared01/paisaje_sonoro/sonido.htm
Autora: Marta García T.
1) Intensity: sounds can be loud or soft, depending on the amplitude of the wave. It is measured in decibels (dB).
- High amplitude loud sound.- Low amplitude soft sound.
Autora: Marta García T.
2) Pitch: sound can be high or low, depending on the frequency of their waves. It is measured in Hertz (Hz).
- High Frecuency high pitch.- Low Frequency low pitch.
Autora: Marta García T.
3) Tone: it allows you to identify the source of a sound. For example, different instruments have different tones although they play the same musical note.
Autora: Marta García T.