Showing posts with label science. Show all posts
Showing posts with label science. Show all posts

Tuesday, June 22, 2010

Nighttime Flowers

As the summer solstice has passed, the longest and brightest day of the year being yesterday, it will now gradually start getting darker.

In the previous post I wondered why the air smells so good at night, so full of flowery scents. It's quite a different experience from the daytime, and somehow it also seems warmer - probably because the cold winds stop as the sun sets.

The reason the air smells different at night is quite simple, to quote professor Natalia Dudareva;
"Plants tend to have their scent output at maximal levels only when the flowers are ready for pollination and when its potential pollinators are active as well. Plants that maximize their output during the day are primarily pollinated by bees or butterflies, whereas those that release their fragrance mostly at night are pollinated by moth and bats."
According to Judy Sedbrook at Colorado State University;
"With the setting of the sun, the nocturnal garden awakens and the night shift takes over. Many plants bloom exclusively at night. Many more wait to release their heady scent until evening."

It turns out some flowers only bloom at night, others release their scent only when dark falls. If you've heard some of their names before, that conclusion might be easy to draw.. at least in hindsight; among flowers that bloom at night are Evening Primrose, Moonflowers, Angel's Trumpet, Night Phlox and Evening Stock.

Among those that release their scent during the night are Night Gladiolus, Climbing Hydrangea and Honeysuckle to mention a few. Even Basil and Oregano-plants give off their scent primarily at night. There's also a long list of white and reflective plants which bloom at night, and seem to glow when they reflect the moonlight. For a more extensive list of flowers, you'll find one in the article entitled The Night Shift


- I don't know about you, but I think I'm going to have to go for a walk tonight :)

Tuesday, March 02, 2010

Earthquakes: Baby, I could feel the earth move!

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You know how people are in bed having the time of time their life, and after they exclaim they could actually feel the earth move? No? I'm sure you've seen it in a movie some time.

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If you were in bed on Saturday when the earthquake in Chile hit, you may actually have felt the earth move. More than it usually does. Which is thousands and thousands of miles a day. And you don't have to be in bed to feel it. But that's beside the point.

According to NASA scientists;
“The length of the day should have gotten shorter by 1.26 microseconds (millionths of a second). “The axis about which the Earth’s mass is balanced should have moved by 2.7 milliarcseconds (about 8 centimeters or 3 inches).”
According to VG this simply means the earth is now spinning faster than it used to. When earthquakes of this magnitude hit, they change the distribution of the mass on earth, which changes the speed at which it rotates. So the continents move, and the earth itself spins faster as a result of it.

An earthquake in Asia in 2004 brought on even bigger changes which shortened the day by 6.8 microseconds. No reason for concern though - we'd need more than 100.000 of these huge earthquakes to see a change of one second in the earth's rotation. Still, it is quite fascinating.


Can you feel the earth move?