Nature Net News
Your source for nature tips
& tricks for exploring nature with your kids
December 2010
Bright Light
"On the fallen and rotting branches
that lay about, I found innumerable small phosphorescent fungi that
glowed with a bright, greenish-blue light, so that part of forest floor
was illuminated like a city seen from the air at night. I collected some
of these twigs and branches, and found that ten or twelve of these
glowing fungi produced enough light to be able to read by, providing you
kept your light source fairly close to the page."
Gerald Durrell
Dear Reader, I remember my first memorable experience with lights found in nature. I was taking my first night hike with my father when I froze like a startled rabbit. There was something glowing in the woods. It wasn't people--we would have heard them by now and it wasn't an animal I knew of. My dad merely chuckled fondly at me and introduced me to foxfire--a bioluminescence caused by certain types of fungi on decaying wood. I was entranced. There were things other than fireflies that glowed. I was determined to learn more. And so, the culmination of my efforts is here in this Nature Net News. Please learn about the various types of "bright light" that one can find in nature. Enjoy! Kathe & Sarah |
When living things produce their own light it is called bioluminescence. If something is fluorescent, that means that it "changes colors" under ultraviolet light.
What to Do This Month:
Check out the Black Light Display at the UW Geology Museum to see natural fluorescence in rocks of all kinds.
Tricks of the Trail for Parents:
What causes fluorescence?
Fluorescence is a physical process where electromagnetic radiation (light) of one wavelength, striking a particular substance, causes an emission of electromagnetic radiation (light) of another, longer, wavelength. Generally fluorescence is caused by the presence of an activator in the mineral. An activator is an element that is foreign to the mineral’s normal crystal structure. When the ultraviolet light hits the activator atom, electrons of the atom absorb the energy and are bumped up to a higher energy level. These electrons then fall back to their original places, giving off absorbed energy in the form of heat and visible light.
Instant Outdoor Expert:
What's that glow?
As shown above, fluorescence is the glow that comes from rocks and other objects under a black light, but what about animals and plants? This glowing of animals such as deep ocean fish is not fluorescence--it is called bioluminescence. Some animals create their own bioluminescence, deep ocean fish and fireflies, being some of the most well-known. Glowing mushrooms are more in the phosphorescence category. Phosphorescence is related to fluorescence, but instead of immediately reflecting the light, the object reemits the light at a slower speed, causing it to glow in the dark. Many "glow in the dark" items use phosphorescence.
Featured Nature Net Site
Nature Craft
UW Geology Museum
Explore the
Geology Museum and take a peek into Wisconsin's deep history!
On your visit you can view rocks and minerals that glow, a model of a Wisconsin cave,
dinosaurs and meteorites.
Our mineral, rock and fossil collections have the power to educate and
inspire visitors of all ages. Come see for yourself!
Want to figure out what has a fluorescence
activator in it?
What you need: black light, whatever objects you want
to test (check out
this site for interesting items).
1. Examine your objects in natural light. What colors are they?
2. Plug or screw in black light and turn on.
3. Turn off regular lights and cover any windows so your black light is the only thing lighting the room.
4. Take your objects and put them under or near the black
light. Are there any changes in color? Do they glow? Glowing means they have a fluorescence activator in
them.
Suggested Reading:
"Creatures that Glow" by Anita Ganeri
(all ages)
"Glow in the
Dark Animals" by Kris Hirschmann (4-8)
"Winking, Blinking Sea" by Mary Batten (4-8)
"Creatures that Glow" by Joanne Barkan (4-8)
"Nature's Living
Lights: Fireflies and Other Bioluminescent Creatures" by Alvin and Virginia
B. Silverstein and Pamela Carrol (9-12)
"World of Fluorescent Minerals"
by Stuart Schneider (9-12)
