Everything we experience comes to us through our five senses—sight, hearing, touch, smell and taste. While our senses are truly amazing, most of what goes on around us occurs unnoticed. Since we can only see a small range of the electromagnetic spectrum as visible light, we can be in the vicinity of a radio-transmitting tower radiating 50,000 watts of power and be totally unaware of its presence. The fluttering of a hummingbird wing and changes in mountain ranges are undetectable to the average human. Extreme distances, both short and long, are equally elusive. We can see the dot above an "i", but cannot see a grain of pollen. At the other outer limits of length, we can only imagine what a light year is.
Scientific research includes the study of subatomic particles as well as the mind-boggling distances that exist between the earth and neighboring stars and nebulae. This great breadth of investigation involves extending our senses and developing new ways of "seeing".
Scientific instruments that enable us to overcome our sensory limitations have been, and continue to be, essential to the progress of science. The microscope and the telescope provide mankind with windows to two previously unseen worlds. The stroboscope has enabled us to "freeze" motion. X-rays have provided a non-invasive way of probing the body. Radio telescopes enable us to extend our grasp to the far reaches of space. Cloud and bubble chambers allow us to study events occurring on the subatomic scale.
In a similar way, the following experiments will allow your students to extend their senses and make measurements they never dreamed possible. They will determine the size of a molecule, time events that occur in an instant, and measure dimensions on an astronomical scale. In the process, they will learn how scientists make observations and measurements in the invisible world.