Neighborhood Nature

Our Family's Nature Blog

First Hard Freeze for Our Jars of Water December 7, 2009

Filed under: Experiments,Fall,Geology,Puzzles and Mysteries,Seasons,Water,Winter — saltthesandbox @ 10:22 pm
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Back on November 29th we started an experiment on our front porch, with four plastic jars filled with water. At the start of the experiment, the jars looked like this:

Water jar experiment, Day 1, November 29, 2009

Here's what the experiment looked like five days ago, before the temperature hit the freezing mark.

Now, here’s what the experiment looked like on Friday, December 4th, after the air temperature went below freezing, hitting 24 degrees Fahrenheit overnight:

Water jar experiment after a hard freeze, December 4, 2009.

Here's what the water jars looked like after a hard freeze. Three of the five jars had frozen overnight: A, B, and D. Also, we had added a fifth jar: In Jar E, the water that had been BOILED first, then cooled, put in the jar, and sealed with a lid that had NO holes in it. (Thanks to J of Science Museum of Minnesota for suggesting this addition to the experiment.)

Three of the jars had frozen water in them, including the jar with SALTY water. No one predicted that! The two jars that did not freeze were both sealed tight — there were no holes in their lids.

Here’s a closer look at Jar A, which started out as cold, fresh tap water, and was covered by a plastic lid with holes drilled in it:

Jar A (fresh water, started cold, holes in top), Decmber 4, 2009, 24 degreees F

A closer look at Jar A shows intersecting sheets of ice, more densely frozen closer to the top of the jar.

Jar B showed a similar pattern, although the sheets of ice were more horizontal than vertical:

Jar B (fresh water, started warm, holes in top), Decmber 4, 2009, 24 degreees F

Jar B also had sheets of ice, more densely frozen towards the top of the jar -- but the ice sheets were more horizontal than vertical.

Jar D was most surprising. I was expecting the salty water wouldn’t freeze, but the top part of the jar was frozen fairly solid. However, the bottom of the jar was not frozen, but had a bunch of bubbles sticking to the side of the jar:

Jar D (SALTY water, started cold, holes in top), December 4, 2009, 24 degreees F

In Jar D, notice the clear division between frozen water above and unfrozen water below.

So, that leaves us with two mysteries to solve:

  • Why did most of the water in the salty jar freeze?
  • Why did the water in the sealed jars not freeze?

I have some ideas, but I won’t tell you about them yet. However, I will give you one hint about the second mystery. Here’s what the lower part of salty Jar D looked like on December 2, 2009 — three days after the experiment started, but before the temperature dropped below freezing:

Jar D (SALTY water, started cold, holes in top), December 2, 2009, 37 degrees F

Here's what Jar D looked like three days after I had mixed in several handfuls of sidewalk salt, but before the first hard freeze. How can this help us understand why the top of the jar froze, but the bottom did not?

Feel free to tell us your ideas in the comments section (below) or on Facebook.

 

An Experiment with Freezing Water November 29, 2009

Filed under: Experiments,Fall,Seasons,Winter — saltthesandbox @ 3:39 pm
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The weather forecast says we’re headed into an extended spell of cold weather, with freezing temperatures predicted for the end of the week. So, it’s time to put some water jars on the front porch to see what happens. This year we’re going to be a bit more organized than usual and set up the jars as an experiment. There are reasons we’re setting it up this way, but we’ll let you try to figure out what those reasons are (with a few hints at the end of this post).

First, here’s our experimental setup: Four PLASTIC jars of water set on our front porch rail this afternoon, here in Oak Park, Illinois:

Water Jar Experiment Day 1, November 29, 2009, Oak Park, Illinois

Here are our four experimental jars of water (all made of plastic). Read the descriptions to see how they differ from one another. We started this experiment on November 29, 2009.

Jar A, on the far left, was filled with cold, fresh tap water. It’s lid has holes in it, so air can get in.

Jar B, just left of center, was filled with warm, fresh tap water. It’s lid also has holes in it, so air can get in.

Jar C, just right of center, also was filled with warm, fresh tap water. It’s lid has NO holes in it, so NO air can get in.

Jar D, on the far right, was filled with cold tap water, then a couple of handfuls of rock salt were added — the same kind of salt you may put on your steps or sidewalk when it snows. It’s lid has holes in it, so air can get in.

So, we are experimenting with the following variables:

  • Does the water start out cold or warm?
  • Is the water exposed to the air or not?
  • Is the water fresh or salty?

Why do we want to experiment with those variables? Maybe you can guess if you check out these blog posts from last winter:

And now, here’s the big challenge:

What do you think will happen to each jar once the weather gets really, really cold?

You will need a separate guess — or “hypothesis” — for each jar, A through D. You can list your hypotheses in the comments section, below, or send them to me by e-mail (eric@saltthesandbox.org) or Facebook.

Think hard, and good luck! (Or should I say, “good skill”?)

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Note: I revised this post later the same day to make it clear that the jars are made of plastic. (Although it might be fun to try it with glass some day. Fun in a Mythbusters kind of way….)

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To find out what happened on December 4th, when the air temperature dropped below freezing, please go here: https://neighborhoodnature.wordpress.com/2009/12/07/first-hard-freeze-for-our-jars-of-water/

 

Look What the Crows Found: A Great Horned Owl! November 24, 2009

Filed under: Animals,Birds,Fall,Seasons — saltthesandbox @ 5:11 pm
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Late this morning I saw at least 14 American Crows in Columbus Park. To me that’s really great — I love crows, but their local population was decreased a few years ago by West Nile Virus. Now that they’re coming back, there’s reason for excitement — you never know quite what’s going to happen when crows are around.

The first crows I saw — a group of nine — were foraging in the woods by the lagoon. Two of them were tearing up a hornet nest. (I’ll post about that later.) They took off when they saw me, heading east and out of the Park.

The next group of crows was only five in number, but they were making lots of noise when I encountered them in the woods along Austin. At first I figured they might be looking for hornet nests — they were in the same trees where I found the nests in this blog post. But they just landed in the trees, took off again, circled over the golf course, then returned to the same trees — calling constantly. The second time they landed it was obvious that they weren’t just calling — they were calling at something. It seemed that they might be “mobbing” a hawk, so I scanned the trees with my binoculars. I thought I might find a Red-tailed or Cooper’s Hawk, which are common in the Park. Instead, this is what I saw:

Great Horned Owl, Columbus Park, Chicago, Illinois, November 24, 2009.

The crows had located a Great Horned Owl -- the first owl I had ever seen in Columbus Park.

The Great Horned Owl was the very first owl I had ever seen in Columbus Park! A few minutes earlier I had walked right under that tree, scanning the surrounding tree tops as I went, but I had completely missed the owl. Good thing the crows helped me out — the owl was sleeping away the day in a White Oak tree. Oaks hold their leaves longer than the other trees in Columbus Park, and the leaves helped hide the owl from view.

I walked a little closer, taking photos as I went. I got within about 75 feet and took this shot:

Great Horned Owl, Columbus Park, Chicago, Illinois, November 24, 2009.

This closer view shows the owl's tufts of feathers, which look like horns to some. It also shows the white neck band, which helps distinguish Great Horned Owls from other species with horn-like tufts.

After a few more photos, I backed away. The crows had left, and I decided to do the same. Time to let the owl get back to sleep.

I hope the crows stick around all winter and beyond. Who knows what they’ll find next time! And I hope the owl finds lots to eat tonight in Columbus Park.

 

Seasons of the Tulip Tree: Almost Full Circle November 22, 2009

Filed under: Fall,Plants,Seasons,Trees — saltthesandbox @ 1:25 pm
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We’ve been following a neighborhood Tulip Tree as it cycles through the seasons. The last time we posted photos was way back on June 18, when the seeds were green, but ripening. The seeds remained that way through most the summer, then gradually started turning brown. Once the leaves had turned bright yellow in late October, the seeds looked like this:

Tulip Tree seeds, Oak Park, Illinois, Octber 27, 2009.

The Tulip Tree seeds are framed by yellow leaves. Also note the duck-bill shaped bud to the left of the seeds.

Soon the leaves were swept off the tree by a wind-drive rain, and something — probably squirrels — found the ripened seeds to their liking. Here is one of the last remaining seed clusters, photographed in early November:

Tulip Tree seeds, Oak Park, Illinois, November 9, 2009.

This was one of the last seed clusters remaining on the Tulip Tree.

Once the seeds have all been eaten or fallen to the ground, the tree will be back to where it started last spring.

You can see our first photos of Tulip Tree buds at the bottom of this post from April 8, 2009.

Go here for our most complete post about Tulip Trees, which starts with the flowers and then goes back in time to how the tree looked as the buds were opening.

 

Last of the Fall Wildflowers at Columbus Park? November 20, 2009

Earlier this year Neighborhood Nature showed the earliest examples of spring flowers we could find. Now that November’s two-thirds gone, I guess it’s time to show the last wildflowers still blooming in Columbus Park. (I’ll do my best to give their names, but bear with me — I’m not a botanist!)

It was sunny and almost warm during this morning’s bird monitoring in Columbus Park. However, some parts of the Park were devoid of birds, so I had time to look down as I listened hard for any birdlike sounds. These nickle-sized flowers caught my eye — I’m pretty sure they’re Daisy Fleabane. (You can see a photo of the entire plant here.)

I'm guessing Daisy Fleabane, Columbus Park, Chicago, November 20, 2009.

Although these look like daisies, the flowers are much too small. So I think it's Daisy Fleabane.

The small patch of prairie habitat beside the lagoon held two plants in flower. The first one looked like a very small example of Queen Anne’s Lace (aslo called Wild Carrot) — the flower head was less than two inches across. (You can see a photo that shows the leaves here. Please use the comments, below, to correct me if I’m wrong.)

I think this one is Queen Anne's Lace, Columbus Park, Chicago, November 20, 2009.

This one looked like a very small example of Queen Anne's Lace (also known as Wild Carrot).

I’m also uncertain what this plant is called. I’m guessing this might be False Dragonhead, a kind of mint. Another name for this species is Obedient Plant, since if you push the flowers to one side, they stay there until you push them back. However, I forgot the try that test today, so my identification has not been physically confirmed. Also, this flower looked more pinkish in the field — I’m not sure why the photos don’t do justice to the color. (You can see a photo of the entire plant here.)

I'm guessing this is False Dragonhead, Columbus Park, Chicago, Illinois, November 20, 2009.

I'm guessing this is False Dragonhead, a kind of mint. (Again, use the comments, below, to help me out!)

My final flowers were just hanging on — most of the others on this plant had gone to seed. It was a kind of thistle, found in Austin woods — but don’t ask me what kind of thistle, I wouldn’t have a clue. (Again, these looked more pinkish in the field. You can see a photo that shows some leaves here.):

Thistle flowers, Columbus Park, Chicago, Illinois, November 20, 2009.

A few thistle flowers remained, but the rest had gone to seed.

“Gone to seed” is where all these flowers are bound. Food for birds, and sometimes a feast for the eyes despite the lack of color. Check out these goldenrod seeds, which may be Showy Goldenrod, one of the most beautiful of its kind. (You can see a photo that shows more of the plant here.)

Gone-to-seed goldenrod, Columbus Park, Chicago, Illinois, November 20, 2009.

Even gone to seed, goldenrods are beautiful.

So, are these the last wildflowers I’ll see this year in Columbus Park? I’ll keep looking for more on future visits. (And I’ll also try to tame that possible Obedient Plant.)

 

Hornet Nests Now Visible in Our Neighborhood November 18, 2009

Filed under: Animals,Bugs,Fall,Seasons — saltthesandbox @ 2:43 pm
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Now that most trees have lost their leaves, we find out what was hiding in their branches all summer long. Bird and squirrel nests are suddenly visible, and hornet nests turn out to be much more common than we ever imagined. I almost never see a Bald-faced Hornet in summer, but now I’m finding their nests in many trees in Columbus Park and throughout our Oak Park neighborhood. They look like big gray basketballs silhouetted against the sky:

Hornet nest, Columbus Park, Chicago, Illinois, November 17, 2009.

Hornet nests look like big gray basketballs or balloons stuck in trees.

But when you get closer, you can see the arcs of hornet-made paper, glued by hornet “spit” to build the outer layers of the nest:

Hornet nest, Columbus Park, Chicago, Illinois, November 17, 2009.

Hornets chew up dead wood, mixing it with saliva to make their own brand of paper.

Some brave creature tore off the bottom of this nest:

Hornet nest, Columbus Park, Chicago, Illinois, November 17, 2009.

I'm hoping whoever tore into this nest waited until all the hornets were gone. (Worker hornets die off each fall, and next year's queen hornets burrow into soil or rotten logs to spend the winter in suspended animation.)

The outer layers of protective paper were torn away, exposing the inner cells — hexagonal tubes that look a bit like honeycomb:

Inside of hornet nest, Columbus Park, Chicago, Illinois, November 17, 2009.

Although the inside of a hornet nest looks like the honeycomb inside a bee hive, hornets build their entire nest with home-made paper (not beeswax).

Now, I’m not going to get all didactic and lecture you about the differences between honeybees and hornets. Let’s just say they both sting if you get too close, you’re not going to get much honey from a hornet, and honeybees won’t help control the fly population around your home. If you want to learn more, check out these online references:

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One of my Facebook friends had some advice for anyone who might consider bring a hornet nest inside for the winter. Patrick wrote, “I remember, as a kid, bringing one inside before the cold had done its deed to the hornets.” In other words, wait until there have been a couple of good hard freezes to kill off any remaining hornets (or other insects) inside the nest.

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P.S. Thanks to the Columbus Park walker who told me where to find the broken-open nest!

 

Cooper’s Hawk in the Brush Pile

Filed under: Animals,Birds,Fall,Mammals,Seasons — saltthesandbox @ 12:41 pm
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For the third day in a row we had a juvenile Cooper’s Hawk trying to pluck House Sparrows from our backyard brush pile. For the third day in a row it came up empty clawed.

Here’s is Monday’s drama. The hawk kept trying to find a route to the very center of the brush pile, where a sparrow cowered on the ground:

Cooper's Hawk in the brush pile, Oak Park, Illinois, November 16, 2009.

Cooper's Hawk in the brush pile, Oak Park, Illinois, November 16, 2009.

Cooper's Hawk in the brush pile, Oak Park, Illinois, November 16, 2009.

Cooper's Hawk in the brush pile, Oak Park, Illinois, November 16, 2009.

Cooper's Hawk in the brush pile, Oak Park, Illinois, November 16, 2009.

As the hawk jumped down to the far south corner of the brush pile, the sparrow scrambled out from the north edge and took off, flying over the fence and through the neighbors’ yards. The Cooper’s Hawk followed as fast as it could, but gave up four backyards north. It flew back to our yard and landed on the fence, were it was greeted by a Gray Squirrel:

Cooper's Hawk facing off with Gray Squirrel, Oak Park, Illinois, November 16, 2009.

Juvenile Cooper's Hawk faces off with a Gray Squirrel. This time the squirrel blinked first, jumping down to forage while the hawk held its perch.

I thought we would be in for another bird-mammal confrontation, which our Cooper’s Hawks always seem to lose. Instead the squirrel calmly jumped into our backyard, where it resumed foraging for stray sunflower seeds.

Since then, we’ve seen the juvenile hawk on our brush pile at least once a day. Each time the sparrows wait until the hawk is on the south edge of the pile, and then they flee to safety.