SAAO - South African Astronomical Observatory


Download the modules by clicking on the titles. (Download Adobe Acrobat Reader free in order to view the modules in PDF format.)

Description of the Modules

  1. The SAAO Sea-Scope
    This is a simple device that allows the users to see under water. Ideal for environmental studies, looking in rock pools, rivers, dams etc. The file includes detailed instructions on how to make a Sea-Scope and where to buy the components.
  2. How Big is the Earth?
    This module describes how the size of the Earth can be found using simple shadow sticks. Eratosthenes used a similar method over 2 000 years ago. It is a cross curricular exercise in that it requires contact to be established with another school/college about 500 kms to the north or south. This communication can be via the internet, fax, telephone or just simple mailing. This need to contact other schools/colleges adds interest to the project.
  3. Large Numbers
    The idea of large numbers is a difficult one for people to grasp and understand fully. How big is a million? or a billion? In this module several different ways are given of introducing large numbers to classes and how to use calculators to handle them. One exercise includes a trip to the nearest star, alpha Centauri. OHP transparencies can be made directly after copying this file.
  4. Alexandrian Astronomy
    An advanced exercise, suitable for Gr 11 and 12 students with a good grounding in geometry. Using a lunar eclipse, or pictures of a lunar eclipse it is possible to work out the size of the Moon and its distance from Earth. The experiment was first performed by Aristarchus and Hipparchus when they were working at the Great Library of Alexandria ca 300 BC. Part of the exercise involves finding the size of the Earth.
  5. The Inverse Square Law
    Most SA textbooks treat the Law of Gravitation and Coulomb's Law as separate laws and nowhere are students told that they are in fact two special cases of a more general physical law known as the Inverse Square Law. This module, suitable for teachers of Gr 11 and 12 students, explains this law and also gives a way of verifying it using simple home made apparatus. OHP transparencies can be made directly once module has been downloaded as a teaching aid.
  6. Comets
    Brief introduction to Comets including their orbits and origins. This leads to a description of making a comet. Since it is not often that teachers have Dry Ice available, it is an opportune time to do several further experiments and demonstrations using Dry Ice.
  7. Calculating the Power of the Sun
    Using either the Inverse Square Law, and some simple apparatus described in #5 "The Inverse Square Law", or some simple geometry the power of the Sun can be calculated. This module is an excellent practical application of module #5.
  8. How far is that Star
    Again using the methods employed in module #5 "The Inverse Square Law" this module describes how it is possible to get a reasonable estimate of the distance to the stars.
  9. Observing the Sun and Sunspots
    There is only one way to look at the Sun safely and that is by projecting an image of the Sun onto a screen using a teleascope or binoculars. This module describes how this can be done and what equipment is needed. What sunspots are and how they can be modelled in a laboratory is also discussed.
  10. The SAAO Telescope Kit
    Using plastic lenses and cardboard tubes the principle of the telescope is explained. The module also contains some explanatory notes on lenses and how telescopes work.

More resources available

The following items can be borrowed from the SAAO Science Education Resources Centre:

  • Posters - a wide variety of laminated posters showing nebula, planets etc.
  • Telescopes - after completing a simple explanatory training session, teachers can borrow a telescope for the day/night.
  • Videos - including the COSMOS series, Meteorites, The Solar System etc.
  • Books - an extensive range of books and other resource materials is available for periods of about two weeks.

For further details contact the Education department.