Photocopy the blank digital watch face shown above. Ask younger pupils, or those in lower-ability groups, to find out how they can make all the numbers from one to 10 by colouring in some of the blanks.

Digital numbers

Use rods (or sticks or pieces of straw) to make times using digital numbers.

l How can you make all the digits from this outline of the figure eight?

* Make a time using as few rods as possible.

* Make a time using exactly 15 rods.

* Make a time using as many rods as possible.

Beeping Watches LESS THAN Suppose a watch beeps once at 1.00, twice at 2.00 and so on.

* How long till the watch has beeped 10 times?

* How many times will it beep in a day?

* How long till the watch has made more than a thousand (or a million) beeps?

Time’s up!

Suppose you are designing a watch that will beep after a certain amount of time. This might be a dinner lady’s watch that beeps after the time allowed to eat a packet of crisps, or a PE teacher’s watch that beeps to show that pupils should change back into their clothes.

l Ask your class how long they think should be allowed for these activities.

* Ask them to discuss and present their findings.

* Time the events to see how long they take.

Jet-setter’s watch

This watch tells the time in different countries. If you don’t have one you can work out the time in different countries yourself. Jamaica is 5 hours behind GMT, China is 8 hours ahead, Nepal is 5.5 hours ahead, Tonga is 13 hours ahead. Ask pupils to: * Work out the time in these places when it is noon in Britain (GMT).

* Work out the time here when it is noon in these places.

* Decide when it would not be sensible to phone these places from Britain.

Time differences for other countries can be found at www.bt.com (click on “at home”, then “find a number” then “international”). You can check the time around the world at www.worldtimeserver.com

USEFUL LINKS

www.timezone.com

Details about new watch technology and designer watches.

Curriculum links

This feature supports:

* The QCA’s design technology schemes of work: developing, planning and communicating ideas and investigating and evaluating a range of familiar products, at both KS1 and KS2.

* KS1 mathematics Y1 unit 78; Y2 unit 79.

* KS2 Y3 unit 79; Y4 units 98,100.