24-Hour Colds
Why you sometimes feel a cold coming on, only to have the symptoms disappear the next day.
Why Is It?
White Clouds
If water droplets are clear, why do the clouds that form from them appear white?
Microwaves
Some people think microwave ovens and cell phones are dangerous, but their fears are not backed up …
Pigeon Illusions
A listener asks: Why do pigeons bob their heads back and forth when they walk?
Tail-Wagging Birds
A listener asks: Why do some birds bob their tails up and down?
Sunscreen Timing
A listener asks: how long should you wait after applying sunscreen before going outside?
Plant Budding
A change in temperature and day length signal plants to form buds in the spring.
Sizing Up Dogs II
A listener asks whether it's true that large dogs don't live as long as small dogs.