HSC Senior Science presented by Liverpool and Zone Science Teachers Association (LAZSTA)

HSC

Senior Sciencepresented by

Liverpool and Zone Science Teachers Association(LAZSTA)

Senior Science

Information SystemsLAZSTA

2010 presented byGreg Pitt

Senior Science Websites

• Board of Studies - Syllabuses• http://www.boardofstudies.nsw.edu.au/syllabus_hsc/ • HSC Exams• http://www.boardofstudies.nsw.edu.au/hsc_exams/

• HSC Timetable• http://www.boardofstudies.nsw.edu.au/events/hsc-exam-timetable-2010.html

Updated information for 2010

http://www.boardofstudies.nsw.edu.au/syllabus_hsc/

http://www.boardofstudies.nsw.edu.au/hsc_exams/

http://www.boardofstudies.nsw.edu.au/events/hsc-exam-timetable-2010.html

Documents You Should Check Out

• NSW BOS HSC Standards Packages[Your school has these]

• HSC examination papers

• Notes from the Examination Centre

• HSC Examination Mapping Grid

• HSC Marking Guidelines

• HSC Sample answers

Communication Activity – Morse Code Messages

classify information systems as: verbal and nonverbal; short distance and long distance; electronic and non-electronic

Class activity… [see handout]

Morse code* communication competition

* created for Samuel F. B. Morse's electric telegraph in the early 1840s, Morse code was also extensively used for early radio communication beginning in the 1890s

Basic Pattern of Information Transfer

Information transfer requires: • the transmitter and

receiver have an agreed code

• encoding• transmission• decoding• energy transformations

often occur when information is transferred

• outline the basic pattern of the information transfer process

• verbal and nonverbal

• short distance and long distance

• electronic and non-electronic

Verbal vs non-verbal

classify information systems as: verbal and nonverbal; short distance and long distance; electronic and non-electronic

Classifying Information Systems

• classify information systems … verbal and non-verbal

Can you identify the verbal and non-verbal components of this sign?

Difficult Points – Information Systems

identify the transformation of energy at each stage of information transfer in the following devices: land connected telephones; mobile phones; television; radios; Compact Disc players

• Land connected phones may use either copper wire (upper part of flowchart below) or optical fibres to transmit the information

Microphone converts sound energy to electrical energy

Earphone / speaker converts electrical energy to sound

energy

Electrical energy transmits information

in a copper cable

Electrical energy converted to light

energy for optical fibre transmission

light energy converted to electrical energy

following optical fibre transmission

Light energy transmits information in an

optical fibre made of glass



The following energy transformations take place in a mobile phone but are not directly associated with information transfer– Energy is stored as chemical

energy in the phone’s battery– Chemical energy is

transformed to electrical energy to operate the phone

– The LCD colour screen converts electrical energy to light energy



Part of phone Energy conversionMicrophone Sound to Electrical

Transmitting antenna Electrical to Electromagnetic (microwaves)Receiving antenna Electromagnetic to Electrical

Screen Electrical to Light



• identify the transformation of energy at each stage of information transfer in the following devices– radios [complete flowchart …]

microphoneconvertssound toelectricalenergy

sound

Aerial convertselectrical energy

toelectromagnetic

waves

Radiomodulatescarrier with

signal -ENCODES

information

Electricalenergy to aerial



• light/sound energy => electrical energy (CCD / microphone)electrical energy => electromagnetic radiation (aerial/antenna)electromagnetic radiation => electrical energy (aerial/antenna)electrical energy => light/sound (screen / speakers)

LightSound

CCDmicrophone

Electrical EnergySignal modulationElectrical energy

to transmitter antenna



• light/sound energy => electrical energy (CCD / microphone)electrical energy => electromagnetic radiation (aerial/antenna)electromagnetic radiation => electrical energy (aerial / antenna)electrical energy => light/sound (screen / speakers)

Televisiondecodes

informationand converts

electrical energyto light and sound

Transmissionas

electrical energy

light

sound

TV screen

speaker

antenna convertselectromagnetic

to electrical energy



• Summary video component

– Light to electrical (CCD)

– Electrical to electromagnetic (transmitting antenna)

– Electromagnetic to electrical (receiving antenna)

– Electrical to light (screen)



• Summary audio component

– Sound to electrical (microphone)

– Electrical to electromagnetic (transmitting antenna)

– Electromagnetic to electrical (receiving antenna)

– Electrical to sound (speaker)

Communication Using Compact Discs

gather and process first-hand and secondary information on the basic pattern of the information transfer process in the following systems: land connected telephones; mobile phones; television; radios; Compact Disc players to outline the features that the systems have in common and use available evidence to discuss applications of these systems

• A compact disc stores binary encoded information using a pits in an aluminium metal layer on the disc

• Light energy (an infrared laser) is focussed onto the pits and a photodiode detects the changes in the reflected energy as the disc rotates





• identify the transformation of energy at each stage of information transfer in CD player

– compact disc players

1.Laser light reflects from pits on CD2.Reflected light energy converted to electrical energy by light sensor

(digital signals)3. Digital signals converted to electrical analogue signals4. Electrical signals amplified5. Electrical energy converted to sound energy by headphones

SYLLABUS point…gather and process first-hand and secondary information on the basic pattern of the information transfer process in the following systems:– land connected telephones– mobile phones– television– radios– compact disc playersto outline features that the systems have in common and use available evidence to discuss the applications of these systems

Common Features• Encoding• Storage• Transmission• Decoding• Energy transformations• Electrical energy use

Applications• Transmission of voice / other

sounds• Transmission of images• Transmission of text• Emergency services• Entertainment• Business and commerce

The E/M spectrum and Communication

identify communication technologies that use energies from the electromagnetic spectrum for communication purposes

Demo IR camera

• Radio - radio waves• TV - radio / TV waves• Mobile phones - microwaves• Fixed phone - light (fibre optics)

Electromagnetic waves do not require a physical medium in which to travele.g. light, radio and TV wavesBut they may travel through optical fibres due to the fibres’ transparency

Live Satellite Communication

gather, process and analyse information from secondary sources to identify the satellites used for ‘live’ telecasts from other regions of the world to Australia and vice versa and to present reasons why communication satellites have different aerials and positional orbits (9.4.4.3.1)

Optus D1 160° east 2006-presentUsed by Sky, SBS, Freeview, ABC (both TV and radio). Coverage New Zealand to Perth (WA).

Optus D2 152° east 2007-present

Replaced Optus B3

D2 also carries a large number of Free To Air channels, many in languages other than English

Optus D3 156° east 2009-present

25% sold to Foxtel to provide High Definition programming as well as "new channels, expanded digital services and enhanced picture and sound quality".

http://en.wikipedia.org/wiki/160th_meridian_east

http://en.wikipedia.org/wiki/152nd_meridian_east

http://en.wikipedia.org/wiki/156th_meridian_east

http://en.wikipedia.org/wiki/Foxtel

Live Satellite Communication

Live Broadcast Satellites Serving Australia


• Optus * 3 satellites• AsiaSat * 3 satellites• PAS2 * 2 satellites• Intelsat * 7 satellites• Inmarsat * 2 satellites• AusSat * __ satellites

Some Service Providers:Netspeed Austar Optus Telstra iHug Newskies MediaSat NTL Heartland Xantic Stratos

Remember TWO of thesee.g. Intelsat, PAS

Broadcast Satellites Positional Orbits


“positional orbits” - yikes! “orbital positions” would be better!

Well OK…• A satellite can only receive and transmit

to a maximum of about 40 % of the Earth’s surface (usually less in practice)

• Therefore, to cover all countries requiring satellite communications services, many satellites are needed in different locations, or geostationary orbital positions

Solar panels convert light to electricity

Broadcast Satellites Positional Orbits


Different Satellites Have Different Aerials


• e.g. PAS2 (PanAmSat 2)• each aerial has a footprint determined

by the transmitting antenna dish size and the direction in which it points

• NSW has good coverage from PAS2• small dishes can be used because of

the short wavelengths of the microwaves used for satellite communications

• The satellite is placed in geostationary orbit so that 24 h service to these areas is provided

Areas covered by different antennas

on the satellite



• This was the view from Aussat 2• With which countries could

Aussat 2 communicate?

• Australia• New Zealand• Papua New Guinea• Japan• Indonesia



• A geostationary satellite above the equator to the north of Australia can provide simultaneous and independent services to Australia and Japan using different aerials.

• To conserve energy (supplied by solar panels), transmissions from the satellite are concentrated in a narrow beam to each location (by using a reflecting dish behind the antenna) solar panel

antennas



Different aerials allow satellites to

cover different footprints

(e.g. Australia and Japan can be covered separately by different aerials on the same satellite) and

send and receive different types of data

(e.g. TV, meteorological data, telecommunications such as telephones)

[Note the 2 reasons] solar panel

antennas

Would you trust these people to put you in space?

N

Copper Cables and Fibre Optics• Capacity: It is difficult to distinguish capacity

from rate of information transfer (a syllabus problem). Capacity could be compared by considering a single wire and a single optical fibre (not bundles of each).

• One method of comparison could be the number of simultaneous telephone calls (<100 with a single copper wire and >1000 with a single optical fibre – figures obtained vary greatly with sources, particularly the date of the source data)

process and analyse information from secondary sources to compare and contrast copper cables with fibre optic cables in relation to; (a) carrying capacity (b) cost (c) rate of information transfer (d) security (9.4.6.3.2)

Copper Cables and Fibre OpticsCarrying Capacity

Optical fibre has a greater information carrying capacity than any other medium, including radio, wireless or copper wire.

Terahertz (1012 Hz) bit rate has been achieved in the lab. As a comparison, the entire useful radio bandwidth worldwide is only 25 Gbps, a mere 0.1 percent of the bandwidth supported by a single strand of fibre. A single strand of optical fiber can easily replace a large bundle of copper wires while significantly boosting system capacity.


Copper Cables and Fibre Optics - Cost


At the canteen, apples cost 65 cents and oranges cost 80 cents.

Discuss the statement “Apples cost less than oranges at the canteen”. (3M)

Copper prices are determined by demand. The cost of copper cables is partly determined by the variable price of copper.



Cost depends on

• Raw materials costs (less for glass than copper)• Final cable cost (more for optical fibre?)• Cost per gigabit of information transferred (much less for fibre)

Much greater amounts of information can be transferred at a much lower cost per gigabit of data to the service provider and consumer.

Optical fibre is therefore much cheaper using this criterion.

Copper Cables vs Fibre Optics – Data Transfer Rates


• Rate: Rate of information transfer can be stated quantitatively in bytes/second (or appropriate multiples thereof).

– To compare rates, the same units must be chosen – it is meaningless to compare MHz to Mb for example.

• This point in the syllabus could possibly be interpreted as the speed at which the signal travels in the cable – about 2 x 108 m/s for light in an optical fibre and a little less than 3 x 108 m/s for electricity in a wire (it’s faster in copper wire).



• There is a common misconception about security in using optical fibres. Both copper and optic fibre can transmit secure data, since both (a similarity) can transmit digital data that can be encrypted so that it is virtually impossible to decrypt (the system is called “secure encryption” and is used extensively for data transmission).

• Signals in copper wires can be ‘tapped’ more readily than optical fibre signals and hence IF the data is NOT ENCRYPTED, copper wires present a greater security risk than optical fibres.

Copper Cables and Fibre Optics - Summary


Capacity Cost Information transfer rate Security

CopperLower Higher Lower Lower

Optical Fibre Higher Lower

Higher>40000 phone calls + >250 TV channels

Higher


Copper vs Fibre Optics HSC05

Question 24(a) Better responses presented a

correct sequence of energy changes with direction indicated by arrows.

(b) Better responses included a good description of the process of digital coding, clearly relating this to the impact upon the development of communication technologies.

Mandatory Investigations

Mandatory First-hand InvestigationsPlanning First-hand Investigations

1. Identify sources of information (bibliography) and read about the phenomenon you’re investigating.2. State the purpose of the investigation.3. Propose a hypothesis that can be tested.4. Identify the variables or factors that affect the phenomenon being investigated.5. Determine which are the independent and dependent variables.6. Propose a method for controlling the identified variables.7. Identify potential hazards and the describe the methods used to mitigate against these.8. Identify and describe (using diagrams where these will clarify the procedure) the equipment, appropriate

technology (including data loggers) and procedure most appropriate to undertake the investigation. Consider use of resources, destructive vs non-destructive procedures and disposal of wastes.

9. Outline the method, clearly identifying the variables to be changed and the variables to be kept constant. Discuss the use of a control.

10. Design the investigation so that it allows valid and reliable data to be collected.11. Identify and use correct units for data that will be collected.12. Identify the orders of magnitude that will be appropriate and the uncertainty that may be present in the

measurement of data.13. Determine how the collected data will be analysed to produce a conclusion related to the aim or the hypothesis.

Mandatory First-hand InvestigationsThings you should be able to write in relation to every FHI

1. Clarify the aim or purpose of the investigation – this should relate to the conclusion.2. Recount the procedure used in the investigation/s conducted to meet the syllabus requirements.3. Identify the investigation as destructive or non-destructive.4. Summarise the observations made during this investigation.5. Identify the data that was collected during the investigation – what quantities were observed or

measured?6. Identify any technology used in the investigation e.g. data loggers, computer simulations7. Identify the order of magnitude of measured quantities and assess the uncertainty present in

measured data.8. Identify the units used in measuring each quantity. 9. Identify the independent and dependent variables.10. Identify at least one significant variable that was kept constant throughout the investigation.11. Propose a reason why it would be important for several groups to carry out the investigation using

the same type of equipment and procedures. Was the procedure reliable?12. Present your findings in the form of a succinct conclusion.13. Compare the investigation carried out with alternative methods and discuss the different

procedures. Suggest modifications and improvements.

Tabulating Results

• Rule up columns

• Label the table with a title

• Label each column with a quantity• Include the units in parentheses with

the quantity name

• Calculate an average value if applicable

In this example, an additional column showing the difference between to two rates could be included.

Person Heart rate before

exercise(beats per

minute)

Heart rate after

exercise(beats per

minute)

John 74 104

Dinh 68 90

Ashish 90 120

Sylvia 88 125

…

average 72 106

Effect of Exercise on Heart Rate

Return

Graphing Results

• Label the graph with a title• Label each axis with a quantity• Include the units in parentheses with

the quantity name on each axis

• Plot data points using an “X”

• Draw a line of best fit if the variables are continuous

• If the variables are not continuous, do not draw a line of best fit - consider using a column graph instead

A word from the creatorThis PowerPoint presentation was prepared

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Greg Pittof

Hurlstone Agricultural High School

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