Programme 1

Activities

Activity 1

• before viewing
• whole-class or group discussion

Find out what your students already know, and what misconceptions they have, about some of the subjects explored in the programme.

• What do students understand by the term ‘digital world’?
• What are some of its aspects?
• What processess in everyday life are largely dependent on digital technology?

• during or after viewing
• whole-class or group discussion

You may find it helpful to stop the video at key points to enable students to discuss what they have just seen.

Alternatively, some of the questions below could be a focus for whole-class or group discussion after viewing, or for individual homework.

For further information relevant to these questions, see the Background and Links sections of these Net Notes.

Digital communications and safety at sea

• How are Mayday and other signals carried to and from the satellite?
• How does digital technology allow sailors to determine their exact position?
• When might a satellite not be able to detect a Mayday emergency signal?
• Why are weight and power consumption limiting factors in the design of portable communications equipment?
• In what other situations could digital communications equipment help save lives?

• In what ways is binary code a universal language?
• What are the advantages of systems which only have to distinguish between ‘high’ (1) and ‘low’ (0) states?
• Why is multiplexing so important to digital communications?

• What is needed in order to set up a remote conference like the one in the programme?
• In what other situations might remote conferencing be a useful way for people to communicate?

• What effect does fine-tuning a television channel have on what you see and hear?
• Why do copies of videos have lower-quality pictures and sound than the originals?
• What is noise immunity, and why does it sometimes break down?

• What sort of information can be held in barcodes?
• How do barcodes help retailers and manufacturers? How do they help consumers?
• What other uses could barcodes have?

• In what other ways is digital technology used to enable individuals to communicate with each other?

• discussion or homework activity
• an offline activity with an online extension

You’re never lost with a satellite

The Global Positioning System (GPS) is a set of 24 satellites that orbit the Earth. The information they transmit allows people with GPS receivers to determine their own location to within as little as 10 metres. Anywhere on Earth, a GPS receiver can always make contact with four satellites. The receiver calculates its position — longitude and latitude — by taking bearings from three of the four satellites. By getting information from all four ‘visible’ satellites, altitude can also be calculated.

1. How can GPS be used to measure:

• horizontal speed?
• direction of travel?
• estimated time of arrival at a destination?
• rate of ascent?

2. Why might GPS receivers prove useful to:

• cross-country skiers?
• car drivers?
• scientists?

3. GPS could be used as a way of monitoring the speed of cars travelling on motorways and other main roads.

• What would be needed to make the system work, and how effective do you think it would be as a ‘speed trap’ for drivers who break the speed limit?

Online extension

• What is the difference between GPS and GIS?

Find out by logging on to these websites:

• http://www.whatis.com/index.htm
• http://www.aero.org/publications/GPSPRIMER/
• http://www.esri.com/library/gis/index.html

• online
• Access the ‘whatis?’ website (http://www.whatis.com/index.htm) to find out more about how information such as email is sent over the Internet. Use the search facility and follow the links to find information about bits, bytes, packets and multiplexing.
• Either individually or in groups, produce a poster to explain how lots of email messages can be sent over the Internet at the same time.

• group discussion or individual homework

Micro-barcodes can be attached to bumble bees.

• Design a method of using barcode readers and micro-barcodes to monitor the movement of bumble bees between genetically modified crops and crops on a nearby organic farm.
• Who might want to carry out this experiment, and why?
• How feasible would your method be in practice?