Tuesday, December 23, 2014

Winter Wonderland—for Squirrels!

Squirrels don’t migrate. And they don’t hibernate. Which means that here in New York City, you see squirrels scampering up trees and into garbage cans no matter the weather: wet, snowy, sub-freezing. How do squirrels survive the cold months?  By building nests called “dreys.” You can see four of them in this photo, taken here in Brooklyn just a few days ago:

Squirrels—we have eastern gray squirrels in New York—start to build their dreys in the summer. While they look like big sloppy piles of leaves, they’re actually pretty strong and stable. Unless they were made by young squirrels—their dreys sometimes are just big sloppy piles of leaves, because they haven’t perfected their architect skills yet.

Dreys start with a solid base layer of branches. Squirrels weave the branches to a tree, usually near the trunk, or where two branches come together, or sometimes, further out on a strong limb. These are the sturdiest places on the tree. On top of the woven branches, builder squirrels add wet leaves and moss. This makes a nice, cozy dry floor for the drey. Then they start building the skeleton of a sphere on top of the base. This is made up of more branches and also, vines. Then the squirrels cover the whole structure with moss, leaves, bark, pine needles, grass, paper—whatever a city squirrel can scrounge that will help keep his drey water-tight and warm.

Squirrels usually live by themselves, or with their newborn babies for a few weeks (just the moms, though, and just in summer and winter, when new broods are born). So why would any squirrel need four nests, as is shown in our picture? One or two nests might be old and rickety—maybe left over from last winter. One nest is the squirrel’s preferred new nest. And one is an extra, in case the favorite nest is invaded by a predator, or becomes infested with lice and fleas. Always nice to have a backup!

Monday, December 15, 2014

Turning Winter to Spring

Here at City Science Kids, we've been performing a little science experiment. We wanted to see if we could make it spring in our Brooklyn apartment—in the month of December! It turns out, we can. By "forcing" bulbs.
Back in November, we bought 4 paperwhite bulbs and 1 hyacinth bulb at our local nursery. Paperwhites are related to daffodils and they look a lot like them, only they're smaller and all-white. Hyacinths are amazingly fragrant purple-blue flowers. Both kinds of flowers bloom in early spring. Instead of growing from seeds, like lots of plants and flowers do, these grow from bulbs.

The International Bulb Society calls a bulb "an underground storehouse and flower factory" that contains everything a plant needs to sprout then flower when the time is right. In the case of paperwhites and hyacinths, that's when the frost first begins to melt. In the middle of the bulb are leaves surrounding the bud itself. And scales that provide all the nutrients the bud will need to grow. Also the roots, which will start to emerge before the bud does. All held together by an outer layer called a "tunic."
Normally to get a flower from a bulb, you stick the bulb in the ground in the fall. It spends the winter underground in cold temperatures. When the ground start to warm, the bulb knows it's time to grow! To get bulbs to grow off-season, you just need to trick them into thinking it's spring. Our nursery kept the bulbs in a refrigerator for a few weeks. Then we brought them home and "planted" them. Really what we did was layer some stones in the bottom of glass pitchers, then we stuck the bulbs on top of them, sprout-side up. Then we added a little water, so the bottoms of the bulbs were wet. After about a week, the roots began to emerge:
And the sprouts got taller and taller and longer and longer. Finally, buds appeared between the leaves.  
After about 5 weeks, the first of them opened up, revealing 6 beautiful white flowers (you can see another bud that will soon open on the bottom right of this plant):
The hyacinth will take several weeks longer to flower. We hope to have purple blossoms festooning our windowsill sometime in January!

Have you got any flowers blooming in your house this month? Write in with pictures!

Monday, December 1, 2014

Presenting November's Most Popular Episode!

Ever since it posted, City Science Kids' most popular episode has been the one on Pickle Science. It featured Brooklyn's own Brooklyn Brine Pickle Factory and its genius, pickle-making owner, Shamus Jones. But in November, our episode on Manahatta—that's what Manhattan's original residents, the Lenape, called the island—suddenly took off like hotcakes! If you missed this episode on what NYC looked like when Henry Hudson sailed up to its shores 400 years ago, you can catch up on it here! If you're a teacher and can't access videos supported by YouTube, watch with your students on SchoolTube.

Also, some of you may be celebrating Christmas and getting ready to buy Christmas trees with your families. Find out how a cut Christmas tree stays green all throughout the holidays, here on CSK or on SchoolTube.

Hope you all had a very happy Thanksgiving!

Tuesday, November 25, 2014

The Ivy Takes Over

Ever since we’ve lived in this particular apartment in Brooklyn, the ivy has been taking over the building. Lately, it’s begun to look as though the ivy might succeed in eating the building whole. It’s gobbled up the back wall as it's climbed the bricks.

And it’s almost completely covered up our windows, suctioning itself to the screens.

Even more lately, the ivy has managed to push its way inside our dining room.

Sound like something out of a science fiction book? It’s just another creepy chapter in the life of English Ivy.

English Ivy—Latin name Hedera helix, and also known as Gum Ivy, True Ivy, and Woodbind—originated in Northern Africa, West Asia and Europe. It was brought to our continent by English settlers in the 18th century. They thought it was pretty. Did they know it was an invasive species, destined to take over cities and forests? Did they care??

English Ivy is so invasive that experts say it threatens native plants and trees. If a tree is covered with ivy, it doesn’t get enough sunlight to achieve photosynthesis. After a while, it withers up and dies. What about (non-living) buildings? If a building is covered in ivy, the ivy eventually begins to gnaw away at the mortar between the bricks, and the bricks themselves. If you try to pull the ivy off, you risk pulling out bits of the building, too.

This excellent article explains how ivy grows. Here’s a riveting excerpt:

“First, the plant makes initial contact with the object it will climb. This then triggers the second phase, when the plant's roots change shape to fit the surface of the structure they will climb. The roots alter their arrangement to increase their area of contact with the wall. Small structures called root hairs grow out from the root, coming into contact with the climbing surface. The plant then excretes a glue to anchor it to the substrate. Finally, the tiny root hairs fit into tiny cavities within the climbing surface. There, they dry out, scrunching into a spiral-shape that locks the root hair into place.”

Apparently, this lets the ivy hold on even when the plant is dead. What do you think, are we doomed in Brooklyn?

Wednesday, November 19, 2014

Remembering Grandpa Dick

Friends of City Science Kids may have noticed that it's been a while since we've uploaded a full  episode. We haven't run out of ideas. We've had a death in the family.

Grandpa Dick passed away a few weeks ago. He wasn't a scientist—although he certainly was a big fan of science. For over 30 years, he was a 4th, 5th and 6th grade teacher. Listening to him talk about his time in the classroom, you could tell it was a lively and happy place. A place where kids could explore their own ideas and be encouraged to figure out how they all fit together.

Once he retired from the classroom, he was a busy Grandpa! He worked to conserve the habitats of ducks and other water birds. He volunteered at the county fair, demonstrating how to make old wood tools and shingles. He taught us how to use tools—even super-scary ones, like the bandsaw:

He tended a bird-feeder that was full of birds that he was always able to identify, and a garden that was well-loved by all sorts of butterflies:

He could make Windsor chairs and replace roofs and put hinges on doors, and he could build the most amazing dollhouse, with windows made of thin slivers of shaved mica:

He arranged trips to make prints of dinosaur footsteps:

And to excavate Herkimer diamonds (here he is, about to bang a bunch of the crystals out of a piece of rock with his sledgehammer):

And just to walk and see what was what:

Sometimes the best visits were to his woodshop—like this one, where he passed on his lifetime's collection of rocks and fossils to us:

Grandpa Dick was a fan of City Science Kids—even though he always had trouble navigating the internet and needed help to watch the videos. And starting sometime last year, he had big plans for it. We joked that he was plotting a takeover! He was eager to introduce us to a friend in the Adirondacks who made some sort of traditional Native American basket. Over the summer, after a birdwatching expedition to the Jamaica Bay Wildlife Refuge, he took us on a detour to meet the man who runs the American Littoral Society. He wanted us to interview him about the upcoming fall migration of raptors (that is, birds of prey like owls and hawks). 

We never did manage to pull off Grandpa Dick's suggested episodes. But City Science Kids is still not the same without him. We'll plod along the best we can, and hope to get an episode out to you soon that would have made him proud and pleased.

Monday, November 17, 2014

The Sound of Not Silence: Jamaican Tree Frogs

The first night we arrived in Jamaica, we were startled to hear an incredibly loud and persistent sound. Not quite croaking. Not quite whistling. More of a high-pitched pulsing coming from the bushes and flowering plants in the courtyard of our hotel. We'd never heard anything like it!

"Tree frogs," one of our traveling companions told us. We researched a little and came up with the species Hyla marianae, Jamaican Treefrog. They look like this:
The sound was probably made by male frogs that were trying to attract mates. And although every night we heard them calling, we never could spot them, no matter how still we stood or how hard we looked. To have a listen for yourself, follow this link.

Friday, November 14, 2014

Seaweed in Jamaica

Everyone who's been to the beach has seen seaweed—both drying on the sand and floating in the ocean. Especially, after a storm, seaweed that's been churned up by wind and strong waves lands on the shore in giant clumps. And since November is storm season in Jamaica, we weren't surprised to see a lot of seaweed on the beach on our first morning there. Mostly it looked like the little patch shown here on the chair—only it was BIGGER and there was A LOT MORE of it.

Why can't you see it in the background of this picture? Because the lifeguard had just spent the last hour raking it all up. And—here's the thing that did surprise us—burying it in this hole:

When we asked him why, he looked at us like we were bananas! "To get it off the beach—it's a nuisance!" he said. He claimed that if he buried seaweed in this hole, in 2 or 3 weeks time the seaweed would be completely decomposed. 

His timeframe may have been a little on the fast side. But it turns out, burying seaweed is a good idea for a couple of reasons. For starters, if it's buried, you can't smell it as it rots and releases hydrogen sulfide gas—which can make you feel sick to your stomach. Second, if it decomposes in the sand—instead of on top of it, where it would also get washed away in addition to being extra-smelly—it provides nutrients to beach plants. (Not seen here: a coconut palm, which was growing right next to this hole.) It turns out, seaweed contains every important plant nutrient there is. They help the soil (or in this case, sand) hold more water for plants to drink. And they also stimulate the stems and roots of the plants so they grow bigger and faster. Hurray for seaweed!

Wednesday, November 12, 2014

Reporting from Jamaica!

This week, City Science Kids is reporting from the Northern Jamaican town of Ocho Rios. Here's a map, showing where in Jamaica Ocho Rios is located:

We've learned all kinds of amazing things on our trip, and discovered all sorts of trees, plants, wildlife, customs we had never encountered before. Like this:

This is the unripe fruit of the ackee tree (scientific Latin name: Blighia sapida). The ackee tree is an evergreen (that is, it stays green all the time) that was brought to the Caribbean from West Africa in the 18th century. The ackee fruit is the national fruit of Jamaica and shows up in the national dish, ackee and saltfish. (We actually tried it at breakfast one morning and it tastes plenty like fish but nothing like fruit. In fact, we thought we were eating a plate of salty, fishy scrambled eggs until our waitress set us straight.) 

But the most surprising thing about ackee is: it's poisonous! That's because it contains a chemical called hypoglycin. In unripe ackee fruit, hypoglycin builds up and if it's eaten, it causes Jamaican Vomitting Sickness—we're sure you can guess what that is! The way to get rid of this chemical is to let the fruit ripen all the way, until it looks like this (drawn here with the national bird of Jamaica, the swallowtail hummingbird):

Then, you discard the big black seeds and any part of the fruit that's colored red, and boil the flesh (making sure you throw that boiling water out, because it will be full of poison). Then you cook it up and eat it with saltfish. Yum!

Wednesday, October 22, 2014

The Wild Cranberry Harvest

October is cranberry season! And in the dunes of Cape Cod, you can find wild cranberries growing in abundance. They grow in the swampy, boggy valleys between high dunes. And they're one of 2 crops native to the salty, sandy soils of New England (blueberries are the other one).

A 19th century ship captain was the first person to grow cranberries for his own use. Why would he want to do that? Because the berries are high in vitamin C, which prevents a disease called scurvy—something a lot of sailors used to get because they didn't have access to fresh fruits when they were out on long sea voyages. The ship captain grew cranberries, and brought them aboard his ship in barrels.

Most people buy cranberries at the supermarket that are harvested from giant commercial cranberry farmers. But we picked them wild in Provincetown, MA two weekends ago. There were so many of them we could hardly carry our full baskets out!

You can read more about wild cranberries in my article in Odyssey magazine:

Wednesday, October 15, 2014

City Science Kids Reporting from Provincetown, Cape Cod

Last weekend, we found this absolutely massive mushroom in the sand dunes of Provincetown, Cape Cod in Massachusetts, where we were picking wild cranberries (more about that later).

This mushroom looks like some kind of bolete (although we don't know for certain). Surprised that mushrooms can grow in the sand? So were we the first time we encountered them—last year, in fact, when we were picking wild cranberries in this same spot. It was our guess that some of the mushrooms we saw were fungal partners for the cranberry bushes. That is, mushrooms that help the cranberries to grow and in return, get sugars and other nutrients from the cranberry bushes.

There's so much scientists still don't know about mushrooms, even scientists who study them all the time. You can learn a little about mushrooms from this past episode of CSK. And from this article I wrote for the magazine Odyssey about mushrooms that glow. Check them out!

Wednesday, October 1, 2014

Summer is Over! Time to Think About...Your Garden?!?

With gardens in both city and country starting to die back for the oncoming winter, let's revisit this City Science Kids episode from the archive: A Garden Gets Ready for Winter.

What are you and your family doing to get your garden—and yourselves—ready for the cold months ahead?

Tuesday, September 23, 2014

It's Fall! Why Are the Leaves Changing Color?

We bet you've been asking yourself the same question! And so have the folks at The American Chemical Society. They put together this short & sweet little video about what happens as the chlorophyll that makes leaves green, starts to dwindle as autumn picks up. Watch it here! Then send in your pictures of the best leaves of fall that you've found so far!

Sunday, September 21, 2014

City Science Kids Reports from the People's Climate March in NYC

Today, 310,000 people made their way down Central Park West for the People's Climate March. Many of them held up signs to let watchers know what about global warming they were concerned about, such as using the fossil fuels coal, oil and gas to heat our homes and drive our cars. The marchers in this photo are all holding posters of polar bears. How does global warming affect these mammals that live up by the Arctic Circle?

Polar bears eat seals that swim in the sea and rest on the Arctic ice. The ice in the Arctic has been melting very quickly because of global warming. This means that the bears have no way to hunt seals—they can't catch them out in open water. So, the bears are starving. According to the organization Polar Bears International, melting ice means that many bears in Russia have been stranded on land. In Canada, polar bear populations have shrunk 22% because of shorter ice-bound hunting seasons. Off the coast of Alaska, some bears attempting to swim from land to ice have drowned—there's just too much water for them to navigate.

Have you thought of ways that global warming affects you or the people and animals you care about? Write in and let us know!

Sunday, September 14, 2014

Making Electricity from the Bay of Fundy Tides

Our latest episode is live! Find out how one power plant in Nova Scotia generates electricity using the tides of the Bay of Fundy. And to read more about Fundy tides—they're the highest in the world!—visit our entry from the summer, here.

Friday, August 29, 2014

Another Milestone for City Science Kids!

This week, we waaaay passed the 20,000 views mark—thanks to all of you! The top 5 favorite episodes of all time (and they're good ones!):

Brooklyn Brine & The Science of Making Pickles (watch it here)
Mushrooms in the City (watch it here)
Elevator B and the Bees of Buffalo (watch it here)
Hot Air Balloon Over Poughkeepsie (watch it here)
The French Fry Boat (watch it here)

We couldn't have done it without you! As the new school year starts, we hope you'll join us for another great season. And as always, teachers, you can check out every episode with your class on our dedicated channel on SchoolTube.

Wednesday, August 27, 2014

Bay of Fundy Tides—Coming Soon!!

Here's another photo to tide (har har) you over, until we can get the next episode up and running! Meanwhile, write in and let us know what science you ran into on your summer vacation.

Friday, August 15, 2014

A New Episode from the Bay of Fundy is Coming!

Here's a little photo taste of what's in store!! Looks like a view of the future, seen from 1969, doesn't it? Knobs, dials, and not a computer in sight. What could it be? (Hint: TIDES!!)

Saturday, August 9, 2014

High Tide/Low Tide in the Bay of Fundy

This is the Bay of Fundy in eastern Canada. At its highest, it is filled with something like 16 billion tons of water. Sound like a lot? It is! In fact, it is equivalent to the flow of all the water in all the freshwater rivers in the world!
The Bay of Fundy is home to our planet's most extreme tides. At high tide (see above), it reaches up to about 55 feet at its innermost point in the Minas Basin (see the map below). 
At low tide—which happens twice every day—the water laps back and back toward the Gulf of Maine. As it goes, it leaves snails,
fishing boats, 
and even islands stranded in the thick red limestone muck that lies at its bottom. 
Why are the tides here so high? It's because of something called tidal resonance. Have a look at the map again. Imagine you are tilting it so the water flows out of the Bay, toward the Gulf. The time it takes for that giant wave of water you'd create to flow all the way out, then all the way back, coincides perfectly with the tides of the Atlantic Ocean. The Atlantic's high tide gives the water in the Bay a big push as it surges back in. Then the water gets squeezed up and up as it enters the narrow Minas Basin and approaches Burntcoat Head, where the very highest tides have been recorded. That's Burncoat Head beach in the photo above—two whole hours before dead low tide!

Stay tuned for a full episode about an amazing feature of the Bay of Fundy's tides, coming soon!

Wednesday, July 30, 2014

City Science Kids is Off to the Bay of Fundy!

That's right, for the next 9 days we'll be vacationing—and looking for science—in Canada's Nova Scotia and the Bay of Fundy. It shouldn't be too hard to find cool stories, since the Bay of Fundy is home to the highest tides in the world! (Although it's shown in the photo below at LOW tide.) Be sure to check back with us soon for our stories from the road!
xxx Lela & Ada

Saturday, July 26, 2014

City Science Kids Presents: How Manhattan Looked 400 Years Ago

In 1609, Henry Hudson sailed into New York Harbor. He found an island that the native Lenni Lenape called Manahatta, which means Island of Many Hills. It was covered in pitch pine forest that was filled with wildlife like black bears and wolves and mountain lions! On Manahatta alone there were 55 different ecosystems!

Today, Manhattan is dense with tall buildings, and overrun with pigeons and squirrels. To find out what it looked like 400 years ago, Eric Sanderson started the Manahatta project. It's become an even bigger project, called Welikilia—he went from figuring out what Manhattan used to look like, to figuring out what Brooklyn, Queens, the Bronx, and Staten Island looked like, too. Sanderson took old maps that were made during the Revolutionary War in the 18th century. Using computers, he laid them over existing maps of the city. In this way he was able to figure out where hills and streams and wetlands and salt marshes used to be. Then he used that information to figure out what plants and animals used to live there. If you visit his website, you can see how every block in the city used to look—before we even had cameras!

For this episode, we visited Washington Square Park in Manhattan's West Village. The land is flat now, and covered in paving stones and concrete. Watch and find out what used to be here!

Special thanks to Eric Sanderson for lending his time and expertise.

Thursday, July 24, 2014

Brooklyn Sycamore Trees in Dead-Summer

As a follow-up to our mini-episode 2 weeks ago, here's a photo showing just how much Brooklyn sycamores are apt to shed their bark in the hot months. This tree is almost all yellow—it must really be GROWING!!

Be sure to watch the episode and to write in with your questions, comments & observations. Have you noticed any shedding trees near you?

Tuesday, July 15, 2014


Lake Minnewaska in the Catskills Mountains in New York State is infested with leeches!
Leeches are worm-like parasites that live in lakes, marshes and streams. They can grow to over 2 inches long and have 5 pairs of eyes. They also have suckers on both ends that are filled with teeth. That's how they clamp on to snails, snapping turtles and even unlucky humans to suck their blood!

How leeches got into Lake Minnewaska is a big mystery—especially since none of the other lakes nearby have leeches. What scientists do know is that over the past few years, the lake has gone from having a lot of acid in it; this made it inhospitable not only for leeches, but for fish, too. To having very little acid; now there are two kinds of fish living in the lake, plus lots of leeches. Recently, the lake was treated with a pesticide called copper sulfate. But it didn't kill the leeches. Swim here at your own risk!

Wednesday, July 9, 2014

City Science Kids Presents: London plane trees are shedding! (A mini-episode)

London plane trees are shedding their bark all over Brooklyn this month. Find out why in this mini-episode (while we continue to procrastinate in getting out our next full episode)!

Wednesday, May 21, 2014

Saturday, May 17, 2014

City Science Kids is Working on a New Episode!

What's in store for Episode #12? Here's a big (but tough) photo clue. Write in with your guesses!

Friday, May 2, 2014

City Science Kids Presents Episode #11: The Science of Sound, Keyboard Style!

And now without further ado, please enjoy our cool new (and very long overdue) episode that explains how pianos & electronic keyboards make sound!

When we started shooting this episode, winter was still raging on the streets of Brooklyn. We wanted to stay cozy and dry so we decided to explore a nice warm indoor theme. And since there is a piano living at our house, we decided to open it up and see what we could discover inside it.

A big fat special thanks for this episode goes to Josh Kirsch of Kirsch Electric—a company that composes music for many of the commercials you see on TV and also for movies. Josh knows a ton about the Moog (the electric keyboard you see in the episode) and synthesizers, because he uses them for his work.

For all you straight-up piano lovers out there, perhaps you already know that the first piano was made in 1709 by a man named Bartolomeo di Francesco Cristofori. He made harpsichords first, but he realized these instruments had a problem—you couldn't make them play softer or louder, only at the same volume. His first piano changed all that. The piano pictured below was made by Cristofori in 1722.

Do you know any fun facts about pianos and other keyboards? Write in and let us know!

Sunday, April 27, 2014

A quick few words about dry ice!

We had some dry ice in the house this week. Dry ice is frozen carbon dioxide—that's the gas we exhale when we breathe. People often use it to ship food, because it's super cold: -109.3 degrees Fahrenheit!!! (As opposed to 32 degree Fahrenheit for frozen water.) And it stays frozen and super cold for a long time. 

In the photo below you can see our dry ice literally freezing the bowl that holds it. All that smoke is actually the ice sublimating. That is, turning directly from ice back into gas—unlike ice made with water, which melts into liquid before turning into gas. 

If you should ever come across some dry ice, make sure you DO NOT TOUCH IT with your bare skin. It's so cold it will give you severe frostbite!

Thursday, April 24, 2014

New Episode Coming Soon! (This time we really mean it!!)

Our iMovie troubles are about to be over so get ready for a new full episode of City Science Kids, coming SOON!! To get ready, here's another clue...

Friday, April 4, 2014

A Little Spring Hello from City Science Kids!

While we suffer through the agonies of iMovie meltdown, please enjoy this photo that is clear proof that Spring is on the way (despite the not-exactly-warm temperatures)! Seen anything blooming in your neighborhood? Send us your pictures!