Energy Transmissions - key concepts student guide Name__

Key Concept
Vocabulary
Assessment


  1. 1.
  2. 2.
  3. 3.
Transverse waves
vibrations
compression
rarefaction
frequency
pitch
wavelength
amplitude
echolocation
cochlea
sound intensity
electromagnetic radiation
transparent
luminous
reflection
translucent
scattering
opaque
convex
concave
focal point
refraction
normal
lens
converging lens
diverging lens
accomodation
total internal
reflection
Science Inquiry Skills
Science as a Human Endeavour
Test
Done @ School

Teacher Signs
Done @ Home

Teacher signs
Science Quest 9 –Main Concepts
Suggested Activities
Extension and Variation Homework
9.1 Matter and energy: Making waves page 316
- Types and parts of waves
- How energy travels in waves
Activity: Use the slinkies to investigate waves. (Sound booklet)
Prac: INQUIRY INVESTIGATION 9.1 Moving energy without matter
Textbook questions: (p317) 1-6



9.2 Sound waves on the move page 318
- How sound travels through different media.
Activity: Tuning forks (Sound booklet)
Prac: INQUIRY INVESTIGATION 9.2 Sound in different media
Textbook questions: (p319) 1-6, 9, 11
Video on sound transmission: http://www.youtube.com/watch?v=GkNJvZINSEY

Extension videos Julius Sumner Miller
1. Sound Pitch and frequency
https://www.youtube.com/watch?v=RXPlHa5mRBE
2. Vibrating strings and bars (beats)
https://www.youtube.com/watch?v=_aPl4Taroow
3. Sounding Pipes
https://www.youtube.com/watch?v=4PyeNPZUKd8
4. Vibrating plates - this pone is fascinating
https://www.youtube.com/watch?v=fj0xjS3BECc
5. miscellaneous adventures in sound Lisajous etc
https://www.youtube.com/watch?v=bINpLtRDuZ0


9.3 Hearing sound page 320
- How the ear works
- The decibel scale
- Cochlear implants
Investigate: The decibel scale p308 (revise the working of the ear, covered in previous unit)
Prac: INQUIRY INVESTIGATION 9.3 Making it seem louder
Textbook Questions: 2-5 p323
Experimental design: Inquiry Investigation 9.4 p 323

Investigate: Q 14 or 15 p323


9.4 The electromagnetic spectrum page 324
- Different forms of radiation
Youtube: http://www.youtube.com/watch?v=cfXzwh3KadE
Textbook Questions: 1-4 p 326
Investigate: Q9 p326


Science as a Human Endeavour -Reportable
Assignment relating to: 9.7-9.10
COMMUNICATION

Choose one of the following Topics:

  1. radio (AM/FM/Digital),
  2. television,
  3. ultrasound,
  4. phones (wireless or landline),
  5. satellites (for communication OR for navigation), internet (with a social or informative spin),
  6. wireless communications,
  7. outback Australians – how they communicate with rest of the world

Answer each of the following questions

  1. How the technology has changed – progression.
  2. Impact on society (positives & negatives), how it’s used in society
  3. How do different people relate to this technology/how comfortable do they feel with it? (Age groups vs socio-economic groups, third world countries)
  4. Relationship to electromagnetic spectrum
  5. How is the energy transferred, types of energy being used?


Yr 9 Energy Transmission Assignment Example answer go here for an example answer
5 min presentation


9.5 Light energy page 327
- How light travels through different media
- Different images formed by reflection
Prac: Inv 9.5 Seeing the light
9.6 Looking at images.
9.7 Floating coin
9.8 How much does it bend?
Textbook Questions: 1,2,3,6,7,8,9,10 p332
Interactivity
Test your knowledge on refraction of light by completing the Bend it interactivity in your eBookPLUS. int-0673
HW book: 9.2, 9.3 and 9.4
Design and Create: Q20 p332– Build a periscope


9.6 Seeing the light page 333
- How the eye works
- How lenses affect light
- What is total internal reflection
Interactivity: Test your knowledge of the lenses used in common items by completing the Time Out: ‘Lenses’ interactivity in your eBookPLUS. int-1017
(revise the working of the eye, covered in previous unit)

Investigation: 9.9 Focusing on light
9.10 Getting a clear image
9.11 Total internal reflection
Why do diamonds sparkle?

Textbook Questions: 2,4,5, 6,7,9,13, 14 p 338

Why do diamonds sparkle?
Seeing in colour; Use the Colour vision weblink in your eBookPLUS to learn more about seeing in colour.
eLesson
Light pipes
Watch this video lesson from the ABC Catalyst television show about how natural light can be used deep inside dark buildings. eles-1087

Digital worksheet 9.5









Class notes
9.1 Matter and energy: Making waves page 316
- Types and parts of waves
There are 2
1. transverse waves are like the waves on water or at the beach.



Energy Transverse_wave.png

2. compressional waves are like the waves in a compressed slinky. Sound Energy travels by this wave.
Energy compression wave Molecule4.gif

Terms about waves
We already know about wavelength and amplitude.
When we relate these ideas to sound amplitude indicates the loudness of the sound. This means a small amplitude is a a quiet sound while a large amplitude is a loud sound.

Wavelength can relate to the frequency of a sound. This is because frequency is a measure of how many crests pass a given point every second. A high pitched sound has a high frequency and therefore a short wavelength.

In music a middle C has a frequency of 256 Hz (Hertz). one octave higher the next C has a frequency of 512 Hz. This C has a shorter wavelength than the lower C. We say it is a higher pitch.

How to calculate frequency or wavelength of sound in air.
1. Sound travels at 330m/s in air ( but faster in water and faster again in solids)
2. given the frequency of the C note is 256 Hz.
the wavelength is 330 / 256 = 1.3m

eg 2
1. sound has a speed of 330 m/s
2. wavelenth is 0.5 m
3. the frequency is 660Hz

or Speed/ wavelength = frequency

In sound when we talk about frequency we are talking about the number of compression per second.

- How energy travels in waves

Hearing and Sound
you need to be able to label all the parts of the ear and know their function - see your text book
Sound volume is measured in Decibels. A whisper is 20 Db, A normal conversation is about 60 Db talking too loud is 75 Db, a lawnmower is 90 threshold of pain is 130 and a jet taking off is 140 - a rock concert is in excess of 120 .

The cochlea implant functions by replacing the role of the cochlea - it transforms vibrations to electrical impulses and these are passed onto the auditory nerve or directly to the auditory processing part of the brain.

Another part of the ear is responsible for balance . this section is attached to the cochlea and are called the semicircular canals. They are oriented in 3 planes (X, Y, Z), The contain tiny grains that interpret your position in space.

EMR
electromagnetic_spectrum.jpg

Reflection

This is a property of EMR. It does not matter what form the EMR takes the principles of refraction always apply. In class we most often talk about Light as our main example of EMR this is because it is easy for us to demonstrate these properties with light.

The rule of reflection is the incoming angle is equal to the outgoing angle. Real rule is the angle of incidence made by a light ray between the reflective surface and the NORMAL is equal to the angle of reflection made by the reflected ray and the normal.

The normal is an imaginary line that is perpendicular (right angles to) the reflective surface.

Refraction
This property of EMR describes how a ray of light will bend as it passes through a transparent object. The angle at which the light is bent (or refracted) depends on the density of the transparent object. However, a general rule is that light will bend towards the normal when passing from a less dense to a more dense object.

The converse is also true i.e.. light will bend away from the normal when passing from a more dense to a less dense object.

This property allows us to focus light.

Refraction and focussing using lenses
A lens uses the property of refraction to bend light in a way that makes it focus at a specific point. We can combine lenses to magnify an object making it easier for us to see its intricate parts. Examples are a microscope or a telescope.

There are 2 types of lenses. The convex lens is the one we have used in our expts. This is where the surfaces bow outward. A concave lens is where the surface bow inward and looks like this.

We can also have concave mirrors and convex mirrors and use them to focus light also. However these only focus reflected light. Reflected light from a concave mirror converges onto a focal point (focus).
Reflected light rays diverge from a convex mirror.

Chap 9.5 do ques 1 to 7

Seeing and light
Our eyes detect a very small part of the electromagnetic spectrum. This is the area that includes coloured light found in the rainbow.
This visible spectrum sits between infrared ( heat) and ultra violet.

In increasing order of frequency and energy the colours are ROYGBIV

Parts of the eye
Light enters the eye through the pupil. The lens refracts the light and focusses it onto the retina. Photoreceptor cells in the retina convert the light energy to electrical impulses that travel along the optic nerve to the brain.

Because there is only one convex lens in the eye the images it focuses on the retina are always upside down. However, our brain reinterprets the signals from the retina and turns it the correct way up. see the diagram below.

So our eye's lens produces a real inverted image on the retina ( real means its projected onto the retina, inverted means upside down and image means picture)

The reason we can see anything is because light is reflected off the object into our eye.

Some rules about reflection
1. a green object reflects only green light - the other coloured lights in the spectrum are absorbed.
ROYGBIV are the colours of the visible spectrum. Therefore in the example above G is reflected and ROY_BIV is absorbed. Eg 2 when you look at a McDonalds sign you see Red and yellow - these colours are reflected while _O_GBIV are absorbed.

2. When you shine white light onto a red piece of cellophane only red light passes through the others are all absorbed. We say the cellophane is a filter.

How do glasses work
We need glasses to assist our body's lens to focus the light reflected from objects onto the correct parts of our retina.

We may need a combination of convex and concave lenses with varying focal lengths to achieve this.
how do glasses work.jpeg

Total Internal Reflection
This is a phenomena that occurs when light appears trapped inside a transparent object.
If a light ray hits an internal surface of a transparent object at just the right angle the ray will be reflected instead of being refracted and passing out of the transparent object. We see this in diamonds that have been cut and polished a particular way.

This image from Physicsclassroom.com shows a ray of light hitting a surface at different angles. The first four rays have an angle of incidence ranging from 0 to 45 degrees and while they show some internal reflection there is also refraction and the light ray passes through the medium.

The last ray bounces off the internal surface of the blue medium and is reflected. Nothing passes through - therefore we call this total internal reflection.
total internal reflection 2.gif

We have found a use for this in communications when we send a laser beam along a glass fibre. The glass fibre can be bent and twisted and still the light beam continues along the fibre till it reaches its end. This is how the internet is provided to devices in the school. ( optic fibre NBN)

This diagram from the BBC.co.uk shows how light could be sent down an optic fibre an be bounced off the internal walls of the fibre.

total internal reflection.png