Quiz! Where is the largest desert on Earth? What continent is it on?
By “largest” I mean square miles. By “desert” I mean …
A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. About one-third of the land surface of the world is arid or semi-arid.
Did you know that the majority of deserts are not composed of sand dunes?
To get you in the mood, here are photos of deserts around the world.
Leave a comment with your answer. I’ll post the answer later today (see below).
Click here for a map (By the way, this map includes the answer but it doesn’t look that way!)
ANSWER: Antarctica! In fact both poles are deserts. The Antarctica Polar Desert is 5.5. million square miles, the Arctic Polar Desert is 5.4 million sq mi and the Sahara is 3.5 million sq mi. Read more about the largest deserts at geology.com.
It cannot be too cold to snow some. It can be too cold to snow a lot. As air gets colder, it can hold less moisture. This is why the Antarctic is the greatest desert on Earth. It’s drier in many places than the Sahara! Climate change is expected to cause more snow in polar regions, not less. Now you know why. (warmer air means it can snow more)
Many birds look ragged right now because they’re molting. July and August are the perfect time to replace worn feathers because the breeding season is over, food is plentiful and they aren’t traveling on migration. The cardinal below looks moth-eaten because he’s molting his body feathers.
What a red bird eats while he’s molting affects his feathers. Red feathers get their color from carotenoids in food so a diet rich in carotenoids makes a cardinal brighter for the coming year.
Bush honeysuckle, though invasive, is a good source of carotenoids. Unfortunately it’s not as nutritious as our native berries.
This bright red cardinal is eating American beautyberry (Callicarpa americana). The redder he is, the better the ladies like him.
This dull colored cardinal must have missed the red berries last summer.
House finches have a more obvious response to nutrition while molting. Finches without enough carotenoids produce orange feathers instead of red. In Marcy Cunkelman’s photo below there’s an orange house finch on the right, a red one on the left.
You are what you eat.
(photos by Bob Kroeger, Marcy Cunkleman, Kate St. John and from Wikimedia Commons)
Today a Quiz. Here are two super sharp photos of plants from very different families. What are they?
Quiz #1: The top photo is a focus stack of 100 images. In real life the image would be 2mm wide so I think it’s been magnified about 80 times. (This one is hard to guess. It helps to squint your eyes to make it look small.)
Quiz #2: The photo below is a focus stack of 70 macro images. What it is?
If you’re desperate for clues, click the links on the captions to view the photo descriptions. Here’s a clue for #2: It’s edible.
Have an idea? Leave a comment with your answer.
p.s. In case you’re curious … Focus stackingis a digital processing technique in which the photographer takes multiple images of the same object at different focal points, then digitally merges the photos to produce a completely in-focus image. The object has to hold still and so does the camera. It requires special software to merge the images.
This video shows how it works.
(photos and video from Wikimedia Commons; click on the captions to see the originals)
Now that the birds are singing again and more singers will arrive on migration, it’s time to practice identifying songs by ear. Yes, it’s hard to do but it’s easier if you can visualize the song.
Just like a sheet of music, a spectrogram of bird song shows how the frequency (pitch) goes up and down. The black dashes graph the frequency and length of the notes. The brown wave graphs loudness in decibels.
Play the matching audio to hear the graph: a song sparrow recorded by Ted Floyd, Xeno Canto XC374118.
Two quizzes follow the video or you can try them independently at the Bird Song Hero Challenge. TIP: Watch the sonogram as it plays! Some of them are tricky.
p.s. Did you know that birds sing harmonies we can’t hear? On the song sparrow spectrogram, above, there are tall vertical dashes during the fast part of the song. The bird is harmonizing with himself in the 12,000 HZ frequency. If you’re older than 30-something, you probably can’t hear it.
Here’s a puzzle. Don’t google it. Look at the photos to arrive at an answer.
In botany: What is a peduncle?
We encounter peduncles every day though we don’t use the word much anymore. Since 1950 the word has fallen out of common use and because it looks like pedophile+uncle the urban dictionary lists a raunchy meaning. But that’s not what it is.
Peduncle comes from ped (Latin for foot) plus -uncle (an Old French diminutive ending) so it literally means tiny foot.
Each photo on this page has at least one visible peduncle. Can you find it?
Here’s a clue. The number of peduncles in each photo above is:
Apples = 1
Black raspberries = 5 (three are hidden)
Elderberries = too many to count
Ginkgos = 9
Final clue: The photo below shows no fruit, but it has peduncles.