For Further Research

Fill a long olive jar with water and place it above a sign reading CARBON DIOXIDE. Use black ink to write CARBON and red ink to write DIOXIDE. Support the jar with a rack cut from a couple of small pieces of cardboard. When the words are viewed through the lens at the right distance, carbon is inverted while dioxide is not. Ask the students why this is so. Hint Both words are actually inverted. Use a baby moon hubcap as a convex mirror. Aim a camera at the reflections on the hubcap to take...

Note about Electronic Parts

The electronic parts for this device are not specified exactly since there are many combinations that will work. Go to an electronic parts store and select a buzzer, battery holder, battery, and switch from what is available. Remember to purchase parts that will fit in a whiffle ball. The store clerk should be able to help you make a workable selection if you need assistance. If possible, test the buzzer before purchasing it to determine if it is loud enough. Test the buzzer and battery before...

Introduction

Except for rock samples brought back from the Moon by Apollo astronauts, cosmic ray particles that reach the atmosphere, and meteorites that fall to Earth, the only information about objects in space comes to Earth in the form of electromagnetic radiation. How astronomers collect this radiation determines what they learn from it. The most basic collector is the human eye. The retina at the back of the eye is covered with tiny antennae, called rods and cones, that resonate with incoming light....

Discussion

Many reflecting telescopes gather light from distant objects with a large parabolic mirror that directs the light toward a secondary mirror which then focuses the light onto a detector. The concave mirror used in this demonstration shows how a concave mirror can concentrate light to form a recognizable image. The image produced with a makeup mirror is not well focused because the mirror is inexpensively produced from molded glass rather than from carefully shaped and polished glass. The light...

Teaching Strategy

The following activities use demonstrations to show how the components of Earth's atmosphere filter or distort electromagnetic radiation. Since we cannot produce all of the different wavelengths of electromagnetic radiation in a classroom, the light from a slide or filmstrip projector in a darkened room will represent the complete electromagnetic spectrum. A projection screen represents Earth's surface and objects placed between the projector and the screen represent the effects of Earth's...