|
|
Friday, 03 September 2010 09:00 |
 By Wendy Langhans
Sometimes I go in search of stories and sometimes they go in search of me. Sometimes...they even pay a visit to my back porch.
While I was watering the plants on our back porch, just before sunset, I spotted a small green leaf on the railing. Being in a mood to tidy-up, I walked over to it. That’s when I got a surprise. It wasn’t a stray leaf - it was a Katydid, most likely a Broadwinged Katydid, Microcentrum rhombifolium (also known as Greater Angle-wing Katydid). And she was waiting for the evening serenade to begin.
|
|
|
Friday, 27 August 2010 09:55 |
|
By Wendy Langhans
Tucked away in on a shelf in my office is a can of compressed gas, which I use occassionally use to clean the dust off my computer keyboard.
The first time I used it, I noticed that the can became really cold, almost too cold to hold. Physicists refer to this cooling as adiabatic expansion: “As the gas expands and does work, its internal energy drops, resulting in cooling.” We see this process at work whenever air flows up and over our surrounding mountain ranges, especially when there’s a bit of humidity in the air: “When the cooled gas makes contact with water vapor in the air, it condenses and forms a mist.”
|
|
Friday, 20 August 2010 09:00 |
|
By Wendy Langhans
What does Leonardo da Vinci, Vincent Van Gogh, the writers of the U.S. Constitution, the writers of the Dead Sea Scrolls and the Native Americans of southern California have in common?
They all used plant galls as a source of black dye.
Oak galls were used to produce iron-gall ink. To make the ink, oak galls were crushed to obtain gallotanic acid. Then the acid was mixed with water and iron sufate and exposed to oxygen. Gum arabic from acacia trees was added as binder, resulting in iron-gall ink. It had an advantage over carbon-based ink; iron-gall ink would not rub off of parchment.
|
|
|
Friday, 13 August 2010 09:00 |
|
By Wendy Langhans
Sometimes it pays to get up early. Like last Saturday, when a few intrepid (or insomniac) folks went for a morning walk with me in Pico Canyon.
Our valley was wrapped in fog, yet the mountains were clear and bathed in the early morning light. Rabbits were out feeding - taking advantage of the transitional time - before the hawks woke up and after most owls called it a night.
|
|
Thursday, 05 August 2010 09:00 |
|
By Wendy Langhans
Have you ever watched people walking? Did you notice how their arms swing in sync with their opposite legs? As the right leg steps forward, the left arm swings forward (and vice versa).
Moving our arms make us more stable and our walking more efficient “by counterbalancing our torso and hips and keeping them from twisting and bobbing too much.”
But what about creatures with legs but not arms, like a caterpillar? How do they maintain their stability, especially when crawling on a vertical surface? When you observe how a caterpillar crawls, you see it moves in waves, moving one segment at a time while keeping the rest of it’s body in contact with the surface. For those of you who swim, the movement resembles a butterfly stroke. For those of you who dance, visualize how the torso can undulate back and forth while krumping.
|
|
|
|
|
<< Start < Prev 1 2 3 4 5 6 7 8 9 10 Next > End >>
|
|
Page 1 of 30 |
