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!