Pencil leads and diamonds are chemically identical; the difference is in the crystal structure.

Martha Foley and Dr. Curt Stager talk about carbon crystals, and what it takes to form a natural diamond.

Blister beetles are common in many parts of the world, including the Northeast. Oily secretions from their joints can raise blisters on skin.The oil has other qualities. It the source of the highly toxic male aphrodisiac, Spanish Fly. Curt Stager and Martha Foley discuss the life cycle and habits of this beetle.

Mutants are neither the creepy brain domes of science fiction, nor the smart-mouth turtles of the cartoons. Mutations arise all the time from environmental exposure to mutagenic substances and from imperfections in cellular reproduction. Martha Foley and Dr. Curt Stager talk change, genetic change.

What draws the line between one species and another?

This familiar household "spider" is not a spider, but an ancient, near relative in the arachnid family.

Why does the moon look bigger when it's on the horizon, than it does when it is high in the sky? Curt Stager shoots down all of Martha Foley's theories.There are a couple ways it could be a trick of the mind, but why then doesn't it work all the time? After physics, optics, geometry and psychology, what are you left with? "Wow, big moon."

Scientists use isotopes of carbon, carbon-13 and carbon-14, to study the age of organic material. But the activity of humans is distorting the clock. Curt Stager tells Martha Foley how added carbon in the atmosphere, pollution, and nuclear testing have made it harder to study the natural world.

Martha Foley and Dr. Curt Stager talk about eye shine, and why some animals' eyes reflect light and others' don't.

The success of the Clean Air Act in reducing acid deposition in Adirondack lakes is an under-reported good news story. Many lakes once devoid of life can now support healthy fish populations and other aquatic life.But as Curt Stager discusses with Martha Foley, the life that returns to recolonize the water is not the same as what was lost. Sediment cores show that the original algae and plankton varieties that form the base of the food chain and were unchanged for hundreds of years are being replaced by different varieties. A balance has been restored, but it's a new balance, tipped perhaps by warming, and by invasive species.

Martha Foley has never succeeded in keeping a nature journal long-term, but Curt Stager finds them invaluable in his work. He records his observations on paper, but also finds great data through researching the journals of past observers, from Samuel de Champlain to Thomas Jefferson, to ordinary little-known North Country folk.His hint - always put it on paper. Whatever became of all that stuff on your floppy diskettes?