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The atomic clock at 50

  • Key Stage 3
  • Popular Activity
  • Topical

Type: Activity
Learning Strategy: Problem solving
Topic: Sound

Invented in Britain 50 years ago, the atomic clock is the silent hero of contemporary communications. It is vital to the smooth running of mobile phones, TV networks, the national grid and the Global Positioning System (GPS). In this activity, students see that caesium atoms in atomic clocks – as well as musical instruments, swings and wine glasses – all have their own natural frequencies. They use the concepts of frequency, amplitude and resonance to answer letters to a teen magazine about paranormal parents and things that rattle in the kitchen!

Published: 9th June 2005
Reviews & Comments: 2

Learning objectives

Students will use ideas about frequency, amplitude and resonance to explain a variety of everyday observations.

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8L sound and hearing
� Sounds are the result of vibrations
� Use scientific language to describe sound waves
� Sounds with a high pitch have a high frequency
� Sounds with a high amplitude are loud

Running the activity

Show page 1 (either projected or as an OHT) and ask students to guess what was invented 50 years ago. Then show page 2, which tells them the answer and gives some amazing information about atomic clocks, including the fact that they measure tiny time intervals by counting caesium atom vibrations. Atomic clocks are accurate to the nearest nanosecond – equivalent to losing or gaining one second in about 33 years!

Page 3 is a guide to frequency, amplitude and natural frequency, using musical instruments, a swing and a breaking wine glass as examples. You could choose students to read this page aloud, taking the parts of the different objects and 'vibrating' their bodies appropriately! Real demonstrations with an oscilloscope would also fit in well here, as well as rubbing a finger on a wine glass to demonstrate resonance.

Each small group needs a copy of page 4. Ask students to discuss or write scientific answers to the letters.

News links

BBC news
This site tells of the invention in 1943 of the atomic clock based on caesium.
Saltford University
Look here for a description – and video – of a successful attempt to break a glass using resonance.
This site has information and film clips about the collapse of the Tacoma Narrows bridge, caused by wind of just the right frequency making it resonate.

Reviews & Comments

Write your online review to share your feedback and classroom tips with other teachers. How well does it work, how engaging is it, how did you use it, and how could it be improved?

Water for all

Mar 31st, 2008

4 Star

Did this with a Year8 class. They all enjoyed the presentation part. Were a bit slow to read about the microbesin depth so ranking them was useful as it also required some discussion about why and how they made decisions.

Reviewer: emer mc dermott

Atomic clock at 50

Jun 20th, 2005

5 Star

I used this with my Y8 class,excellent for discussion and groupwork

Reviewer: Doris Evans