Principle 26. Copying

1. Instead of an unavailable, expensive, fragile object, use simpler and inexpensive copies.
   Virtual reality via computer instead of an expensive vacation
   Listen to an audio tape instead of attending a seminar.
2. Replace an object, or process with optical copies.
   Do surveying from space photographs instead of on the ground.
   Measure an object by measuring the photograph.
   Make sonograms to evaluate the health of a fetus, instead of risking damage by direct testing.
3. If visible optical copies are already used, move to infrared or ultraviolet copies.
   Make images in infrared to detect heat sources, such as diseases in crops, or intruders in a security system.