A January Walk through Columbus Park

As I monitored birds this morning in Columbus Park, I did an experiment. I took photos with my iPhone and uploaded them live to Facebook. It was kind of like a virtual nature walk!

Here the link to the public Facebook album with this morning’s photos:  A January Walk through Columbus Park.

Please let me know what you think!

First Hard Freeze for Our Jars of Water

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:

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:

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:

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 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:

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:

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.

Our First Ice of the Season!

According to the closest Oak Park weather station, the temperature hovered just above freezing early this morning. But skies were clear, so heat radiated from the upper layers of our backyard pools. By dawn we had our first backyard ice of the fall:

Ice formed as heat radiated from the surface layer of water.

If it had been cloudy, or if there had been a breeze to circulate the water in the pool, we wouldn’t have had ice. But with a clear sky and calm air, we got these fantastic ice patterns right outside our back door!

Why the triangles in the ice? I’m not sure, but that’s the pattern we got last year in similar situations. If you look at this blog post from last February, you’ll see another example of triangular-patterned ice. That post talks about “wrinkles” forming in the super thin ice — maybe triangles develop where three wrinkles intersect. Anyway, that’s a puzzle for me to work on over the next few months.

There’s no natural water where kids can go and play, except after big storms and snow melts, and they set things up so even that’s supposed to drain away. There are no streams, no lakes closer than Columbus Park — just some human-made garden ponds in fenced off yards. And the Park District swimming pool. And the drainage ditches along the highway, which have cattails and Red-winged Blackbirds and mosquitos, but those are also fenced off too. But there’s no stream or pond or swamp where I can let the boys wade free, throwing rocks, racing sticks, collecting frogs and eels.There’s no place like I had growing up.So, we import our water through pipes, then fill containers in our back yard. There’s a plastic swimming pool where our pet turtles swim in summer; another half sand, half water, with a pump to make a stream; a pool with buggy water from the golf course pond behind Grandma’s condo; a black container for panning gold; and a pool that’s just for playing.

Every fall I promise to drain the pools and store them, but it never happens. Then I wake up on a winter morning and find this

Two More Signs of Spring at Columbus Park

A Mourning Cloak Butterfly, out of hibernation and trying to warm up:

Apparently a dark plastic trash bin in the sun was the warmest thing around.

A fisherman on the bank of Columbus Park lagoon:

The fisherman I talked with said he hadn't caught anything yet, but that was OK -- he was "just playin'."

The Cold Is Back — But So Are the Robins

It was 19 degrees Fahrenheit and windy on this morning’s walk through Columbus Park. Despite the wind chill, I enjoyed both the patterns in the ice and the scores of Robins feeding on the golf course.

The most interesting ice formed at the edges of golf course puddles:

The surface water froze as the water below slowly soaked into the soil.

I saw at least 80 Robins, almost three times what we saw on Sunday.

Eight American Robins in the foreground, with white Gulls and a black Crow on the golf course behind them.

Most Robins fed on the golf course, on the east sides of wooded areas. There the early morning sun warmed them while trees sheltered them from cold west winds.

Tuesday’s warm front brought the Robins to the Park and filled the puddles. As usual, a cold front followed — its bitter winds froze the puddles and the soil. If the Robins can’t find worms, they’ll probably switch to fruit, their winter food. That’s why we put out raisins for our backyard Robins.

To read about other birds we’ve been seeing in the Park, go to this page.

To read about whether Robins are a reliable sign of spring, go to this page.

——

Nature Note added at 6:15 p.m. the same day: Late this afternoon I watched as our backyard Robin pulled a huge nightcrawler from the soil below the thistle feeders. It was so big he had trouble eating it. I guess I won’t have to worry about that Robin, despite the freezing temperatures.

Nature Note added at 6:50 a.m. the next day: It was 16 degrees this morning. When I saw a Robin in a tree near our yard, I did worry. So I put out more raisins.

Nature Note added on March 28 (more than 2 weeks later): This past week there have been even more Robins in the neighborhood. On Friday, March 27, I found at least 200 Robins in Columbus Park, mostly on the golf course. On Tuesday, March 25, I counted 136 Robins on a 2.5 mile walk through south Oak Park.

Refilling Ancient Lake Chicago

Our neighborhood was once the bottom of a lake. That lake shrunk in size to become Lake Michigan, but ten thousand years ago the larger version covered most of Chicago and Oak Park. That prehistoric lake is known as “Lake Chicago.”

When rains are long and hard, the ghost of Lake Chicago tries to make a comeback. Storm sewers usually rescue residential areas from its return. But, after three and a half inches of rain over the past weekend, Lake Chicago has returned to Columbus Park:

Canada Geese swim across the flooded ball fields in the southeast corner of Columbus Park. The white flecks in the background are hundreds of gulls on the partially flooded golf course.

Hundreds of gulls fed and loafed on the soggy golf course. Photo by Ethan Gyllenhaal.

Jens Jensen knew about the prehistoric lake when he planned Columbus Park a century ago. He incorporated ancient beach ridges into his design. I don’t know if he planned the flooded ghost of Lake Chicago — if so we birders appreciate his efforts.

Visiting the flooded Park as the storm subsided, the boys and I checked every gull and goose. We hoped to find rare visitors who nest much further north. In previous years we’ve seen a Snow Goose, three Ross’s Geese, and two Greater White-fronted Geese in the Park. This time we only found a Cackling Goose, a much smaller relative of the abundant Canada Geese. About dozen gulls visit the Park on most late winter days, with larger pink-legged Herring Gulls out numbering the yellow-legged Ring-billed Gulls. The floods brought hundreds more Ring-bills to the Park, but so far no rarer gulls, like Glaucous, Great-black Backed, or Thayer’s. (We’ve never seen those in the Park, but we can always hope.)

On Tuesday, another warm front brought south winds and heavy rains to our neighborhood, so the fields should stay flooded for a few more days. We’ll return to Columbus Park to see what migrant birds rode the winds to our neighborhood. To read about what we find, you can check our eBird lists for Columbus Park.

Wading Pools in Winter and a New Theory of Dinosaur Extinction

With today’s temperature in the 50s, I urged Aaron and his friend Matt to explore the backyard instead of the icy expanses of Club Penguin. Eventually they agreed, leaving penguins but not ice behind.

Within minutes they called me to the backyard to record a “discovery” they made. I took some photos and wrote a story to go along with them. (The story was inspired by dinosaur books for kids, which I’ve been reading in preparation for a writing project.)

This only happened because we leave out plastic pools filled with water all winter long. That’s one way we make our neighborhood a better place for outdoor play, a place with No Child Left Inside.

—–

Aaron and Matt found a dinosaur disaster in our backyard! An imaginary world of dinosaurs and ice was being destroyed.

What had done this terrible thing to Ethan’s old collection of giant plastic dinosaurs? (Ethan is Aaron’s older brother — he’s loved dinosaurs since he was a little kid.)

Can you help us solve this mystery?

Matt carefully studied the ice layers searching for clues:

The ice, unfortunately, held no useful clues to the origin of this disaster.

The team decided to excavate in search of answers. After much digging and clearing of ice, Matt reached into the water with his bare hands. He pulled out a giant rock!

Matt pulled out a giant rock, the cause of the disaster.

It was obvious that a flying rock had shattered this icy world. But where did the rock come from? From outer space? From a volcano? Gradually, the true cause of this disaster became apparent, as the rock struck once again:

The rock struck again -- how did that happen?

The rock then smashed into another pool.

Aaron and Matt imagined the rock had come from space — that was their Theory of Dinosaur Extinction. Should I believe them?

Do you have a better theory? Who will Ethan agree with?

——————–

Thanks to Aaron, who let me tell the story my way, instead of the way it really happened.

With my kids, throwing rocks and smashing ice happen so predictably that they seem almost instinctive. The boys adding characters and plot to the adventure also seemed quite natural. I’ll let evolutionary psychologists explain how these behaviors contributed to our ancestors’ survival on the plains of Africa.

Here’s something that occurred to me — by destroying the ice, the boys found out about the physics of ice, water, and flying rocks. They also learned biology — the smell of dead leaves festering on the bottom of the pools. Smashing things may be the starting point for certain kinds of science, although building things and understanding wholes no doubt have different roots.

And the gender thing: Parents of boys may see more of this than parents of girls, and grown-up boys may better appreciate these images. But if Aaron and Matt’s friend Hannah had been here, she would have been in the thick of it. That’s one reason she’s their friend, and I’m glad they’ve made room for her.

Salty, Super-Cooled, Heat-Sucking Slush — and Homemade Ice Cream

We have a couple of inches of new snow in the neighborhood this morning, so I thought I’d tell you about something “cool” we did with snow. It’s great to do this with new snow, but even if the snow in your yard is already melting or turning gray, that’s fine.

This is as much science as nature, so here’s our research question: What happens when you add salt to snow? The kids in our house that day voted three to one for this hypothesis: “It will get warmer.” Why? “Because salt melts snow.”

Was the majority correct? Let’s do an experiment to find out!

Here’s our experimental apparatus:

We used a large bowl of snow, a bunch of ice-melting salt, a large metal spoon, and a thermometer left over from Nature and Science Club.

First we took the temperature of the pure snow:

The thermometer reads 0 degrees on the left side (Centigrade) and 32 degrees on the right (Fahrenheit).

The snow was at the freezing point of water: 32 degrees Fahrenheit, 0 degrees Centigrade.

Next we mixed a bunch of salt into the snow:

The metal spoon was strong enough to mix the salt and snow without breaking.

We stuck the thermometer into the mixture, watched, and waited. Here’s what happened:

The thermometer read -22.5 degrees Centigrade, -9 degrees Fahrenheit.

Three of four kids were very surprised — the mixture had gotten colder — much colder! Their hypothesis was wrong — but why?

Ethan, who remembered doing this experiment with our old school’s Nature and Science Club, explained it this way: “Because the salt lowers the freezing point of water.” That’s a good start, but remember one more thing: It takes heat to melt snow, and that heat has to come from somewhere. As the salty mixture reached a new balance between liquid and frozen water, heat was sucked out of the mixture,and its temperature dropped. Steve Spangler puts it like this:

When salt is added to the ice (or snow), some of the ice melts because the freezing point is lowered. Always remember that heat must be absorbed by the ice for it to melt. The heat that causes the melting comes from the surroundings.

So, we had this very cold mixture of salty, heat-sucking slush. We couldn’t just let it sit there — we had to put it to use. As Ethan remembered from Nature and Science Club, salty slush is just to thing to suck the heat from a mix of cream and sugar — to make ice cream!

We looked up directions for homemade ice cream on the Web, and kind of followed the ones on Steve Spangler’s website. However, we couldn’t find the vanilla, so we used chocolate sauce instead:

This is what we used to make homemade chocolate ice cream.

We mixed the half-and-half, sugar, and chocolate sauce inside a heavy-duty zippered bag:

We squeezed and sloshed the bag to make the mix.

Then we put the sealed bag of ice cream mix inside a second zippered bag packed with salty slush. The most important direction was to keep the ice cream mix (half-and-half, sugar, and flavoring) separate from the salty slush:

Make sure the bag of ice cream mix is sealed really tight!

And then we held the bag of slush with a really warm glove and carefully shook and jiggled it for 15 minutes.

Make sure that your bare hand never touches the salty slush, and the bag of ice cream mix doesn't leak.

When we were done. it looked like this:

It looked good enough to eat -- so we did!

Everybody had a taste:

Aaron liked it! And so did everybody else.

The ice cream was super smooth, because thousands of tiny ice crystals formed as the super-cooled salty slush sucked heat from the mix.

Hurrah! The Ice and Snow Are Back!

We’ve been so immersed in searching for signs of spring that we almost forgot how wonderful winter can be. Then, on our second morning of low teen temperatures, we woke up to this:

Here's what our front-porch jar of water looked like after the second night of temperatures in the low teens.

Water is such interesting stuff, and it may be most interesting in early spring, when temperatures fluctuate around the freezing point.That’s why we leave containers of water sitting around outside, like the plastic jar of water on our front porch.

In this case, I think the streaky things are bubbles formed as dissolved air was forced out of the freezing water. The water froze from the outside in, pushing the ever-growing bubbles along as freezing proceeded inwards. There’s even a core of unfrozen water in the center, with air bubblettes accumulating into one big bubble at the top.

With predictions of 4 to 8 inches of snow falling from tonight through Saturday, I’ll have more than enough excuse to post more stories about exploring ice and snow. Maybe we’ll get back to spring late next week.

Imported Water Turns to Ice

I have this problem with our neighborhood: There’s no natural water where kids can go and play, except after big storms and snow melts, and they set things up so even that’s supposed to drain away. There are no streams, no lakes closer than Columbus Park — just some human-made garden ponds in fenced off yards. And the Park District swimming pool. And the drainage ditches along the highway, which have cattails and Red-winged Blackbirds and mosquitos, but those are also fenced off too. But there’s no stream or pond or swamp where I can let the boys wade free, throwing rocks, racing sticks, collecting frogs and eels.

There’s no place like I had growing up.

So, we import our water through pipes, then fill containers in our back yard. There’s a plastic swimming pool where our pet turtles swim in summer; another half sand, half water, with a pump to make a stream; a pool with buggy water from the golf course pond behind Grandma’s condo; a black container for panning gold; and a pool that’s just for playing.

Every fall I promise to drain the pools and store them, but it never happens. Then I wake up on a winter morning and find this:

Not wrinkled plastic wrap -- it's wrinkled ice!

Our gold panning pond, filled to the brim with melt water by a string of warm days, was sealed with ice. It wrinkled as breezes blew across the surface when the ice was super thin, like plastic wrap. And it happened even though the air temperature never got below 33 degrees. The surface waters must have lost their heat to clear skies above, until they were colder than the air, cold enough to freeze.

The boys went out the front door to school. If they had found the ice first, they would have marveled at its beauty — for about 2 seconds. Then they would have picked it out like a sheet of glass, or thrown small rocks on its surface to see if they broke through. Ice, as a plaything, even works for middle schoolers.

Of course, I want to get all educational about it. So, I just put a jar of water on the front porch rail:

Today this jar is filled with water, but tonight's temperature will be in the mid 20s. Check back tomorrow.

Tonight it freezes, and the next night, and the next, although it will be warmer in daylight. When Aaron wakes up and asks if it’s cold out, I tell him to look out the front window.

For you, I’ll take a picture, and post it here.

———————

It’s Friday morning, February 13. Early this morning the temperature dropped to 28 degrees under clear skies, and this is what we found just after sunrise.

The back yard pond had frozen, but with a twist:

Can you see the evidence that the ice was broken, and then healed?

The newformed ice had been broken overnight, and then had time to heal. See the shards of ice and round bubbles embedded in the ice sheet, and the wet spot on the edge? Maybe it was the local possum, stepping on the ice or breaking through for a drink.

The jar of water on our front porch had not frozen. Perhaps, protected from the clear skies above, it didn’t lose enough heat to freeze.

And I almost forgot this morning’s frost! At 9 a.m, there was still a bit preserved on the shady side of the neighbor’s garage roof:

The sun has melted this morning's frost, except in a few shady spots.

———————

It’s Saturday morning, February 14. Early this morning the temperature dropped just below 30 degrees under cloudy skies, plus there was almost an inch of new snow. This is what we found just after sunrise:

Look what happened to our water jar on the front porch: It's still, mostly water, but there's ice at the edges.

Look what happened to the pond in our backyard: The ice is now covered with a bit of frozen slush and snow, and there are icicles hanging from the edges.