Wednesday, April 30, 2014

Libraries as refuges for children

Cevan Castle is a recent graduate of Columbia's School of Architecture, and he participated in the Architecture League's collaboration with Little Free Library's efforts to make beautiful, free libraries for communities. His design was good, and his statement resonated with me:

Libraries are shelters for people, as well as books. Children, especially, rely on libraries as a safe destination outside of home or school. Books are not the only attraction. The activities that congregate in and around the library collection—such as storytelling, tutoring, clubs—allow children to connect with each other and share in a safe place. New York City is not particularly friendly to children. The presence of a neighborhood library gives our smaller residents a destination and means of connection. I propose that Little Free Libraries could help children find an anchor in an otherwise adult-sized landscape.

I grew up in libraries, and our recent experiences at SF Skate Club have shown me how important these places are to children. Places that are not school, and not home, where they can have unstructured social time with other children, but feel safe in the presence of adults. Libraries fulfilled that purpose during my childhood.

Tuesday, April 29, 2014

Paragliding physics

We've been learning about the physics of flight (lift, thrust, drag... those things). So far we've looked at balloons and planes. Today, a paraglider friend gave us a demonstration on the beach.

The 30-foot wing fits in a backpack and looks like a massive plastic shopping bag:

The holes in the front fill up with air, inflating the wing:

When the wing has acquired its shape, it starts to generate lift...

And we're up and running!

Talking about how air pressure creates lift has been an opportunity to introduce Newton's laws of motion (particularly law 3, for every action there is an equal and opposite reaction). Here's a short presentation about these forces in the context of paragliding.

Saturday, April 26, 2014

Skateboarding with SF Skate Club

On Friday mornings E has been learning to skateboard with another homeschooled boy. Their teacher is Shawn Connolly, bona fide skater and founder of the San Francisco Skate Club.

I too skateboard and the children's uncle used to skate professionally, so there are lots of skateboards around the house. There are also plenty of skate parks in the Bay Area, and they're empty in the mornings (skaters aren't early risers). Perfect for kids to learn.

Sometimes the girls and I tag along to hang out with them and see what new tricks E has learned:


Shawn and his wife Thuy have been running the SF Skate Club for seven years now. They integrate skateboarding lessons with other creative and educational projects. They run an arts program, painting skateboards, making stickers, teaching film & photography and doing crafts such as sewing.

They recently opened a clubhouse two blocks from us, and our children hang out there almost daily. There are few such places for children to spend social time in an unstructured way with other children outside of home and school – what sociologist Ray Oldenburg would call The Third Place.

It's great to have them in the neighborhood! Also, the skate lesson is on Meetup, and there are still slots left for a couple more kids at this time.

Friday, April 25, 2014


Today we talked about the units that make up the things around us – cells (in living beings), molecules, and atoms.

We reviewed the atom video (not everyone had seen it) and created a model of a water molecule out of poster board, construction paper, and string.

The water molecule is great because it's so simple: one oxygen atom and two hydrogen atoms.

Here's my script for the lesson:
  • Try chopping an apple into smaller and smaller bits. If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further? In ancient Greece, Democritus asked this question. He reasoned that it had to end at some point in the smallest possible bit of matter. He named this basic matter particle an atom. It means "indivisible" in Greek.
  • What does an atom look like? Nobody can see them directly, they are so small. We have to imagine them. Physicists are people (mostly grown-ups but some teenagers ands kids too) who think about this stuff a lot. In 1897 (around the time our house was built) an English physicist named Joseph John Thomson, who lived in Cambridge and taught physics to students there, was experimenting with electricity. He discovered something unexpected: that atoms have a nucleus made of even smaller particles called protons and neutrons, and one or more electrons orbiting it much like planets orbit around the sun. The orbits of electrons are called shells. Now, over a hundred years later, almost everyone imagines atoms this way.
  • J. J. Thomson also suggested another thing: that not all atoms are the same. Different atoms have different numbers of protons, neutrons and electrons. Atoms always want to have a certain number of electrons on their outer shell: two on the first shell, eight on the second.
  • When you put atoms together, some of their electrons get shared between the atoms. This binds the atoms together, forming a molecule.
  • A water molecule is formed when one oxygen atom binds with two hydrogen atoms. They do this because the oxygen atom has six electrons on its outer shell. How many is it missing to be happy? Two. The hydrogen atom has only one electron. How many does it need? One. So, when two hydrogens and one oxygen find each other and bind, they form a molecule of water: H

The children like chopping things up and putting water into smaller and smaller droplets. Also, pointing to things and asking each other "is this made of cells?" and "what is this made of?" (they know the right answer is always atoms but sometimes they know some of the molecules too).


PS. A good source on the history of atoms here.

Thursday, April 24, 2014


While visiting friends in Los Angeles this week, we have been learning about physics. It started with an inevitable question on the plane from San Francisco: How can something so heavy fly?

It's tempting to geek out on the answer, but the below clip summarizes the gist of my explanation attempt. (No doubt we'll be returning to this one!)

As soon as we arrived the children discovered a bunch of balloons left over from an easter egg hunt, and proceeded to experiment by tying a basket to them and adding and subtracting balloons to see how many were needed to get the weight to rise up.

Having succeeded in this, they then encountered the problem of getting the balloons back down from the ceiling:

A number of recovery attempts were made, including an audacious one by our friend Ben involving use of the remaining balloons to lift a string connected to a clothes pin held open by a melting ice cube. (Ultimately the children had success with a simple ladder).

By now we had made some comments about air and gases, and why helium made the balloons rise up, in contrast to the plane.

On the second morning at the pool one of the girls asked, "What is water made of?"

This launched a discussion about the elements, molecules and atoms. The children enjoyed asking each other what various things were made of (wool? smoke? another child's ear? the sun? pee?)

Until E asked "If everything is made of atoms, then what about the atoms?"

At this point we watched this animated video about atoms. (There's an explanation of how hydrogen atoms bind to oxygen to form a water molecule at the end).

We then spent the afternoon at Griffith Observatory on the Hollywood Hills, which is filled with models of celestial bodies – strikingly resembling the atoms from the morning.

Tomorrow we'll pick up from where we left off,  and start by watching The Powers of Ten, one of my favorite science film classics. We also use The Physics Book: From the Big Bang to Quantum Resurrection and other resources in the classroom.

Monday, April 21, 2014

Writing letters

Today we talked about writing letters, sending and receiving them, and also what it's like to be illiterate.

We passed around, opened and read some old letters C had saved from years ago:

We then recited this poem about an illiterate man, who received a letter, but didn't know who it was from or what was in it:

The Illiterate

Touching your goodness, I am like a man
Who turns a letter over in his hand
And you might think this was because the hand
Was unfamiliar but, truth is, the man
Has never had a letter from anyone;
And now he is both afraid of what it means
And ashamed because he has no other means
To find out what it says than to ask someone.

His uncle could have left the farm to him,
Or his parents died before he sent them word,
Or the dark girl changed and want him for beloved.
Afraid and letter-proud, he keeps it with him.
What would you call his feeling for the words
That keep him rich and orphaned and beloved?

The man was ashamed he couldn't read. We talked about what it means to be ashamed of something, and some of us shared personal stories. It was a great conversation!

We had also brought out different kinds of stationary, and talked about how a writer can express feelings and ideas without using words.

Everyone chose somebody they wanted to write a letter to, and we spent a good chunk of the morning composing our letters. Some children wrote more than one. Grandparents, friends, even a friend's dog got one.

We then wrote addresses on the envelopes, attached stamps for domestic and international destinations, and walked the letters to the mailbox down the street.

I think everybody felt like they had touched someone far away.

Update: we just learned that April is National Card and Letter-Writing Month – who knew!

Thursday, April 10, 2014

Archery on the beach

The children's interest in archery, which has been going on for a while, has led us to set up a regular archery practice on Thursdays in a safe area between the sand dunes at Ocean Beach. We announced it on Meetup, and this attracted a bunch of other homeschoolers and friends.

It's one of my favorite activities during the week – we have the beach mostly to ourselves, and the children find all kinds of interesting things to do when they get tired of honing their skills with the bow and arrow.

Wednesday, April 9, 2014

Green School in Bali

Our friend sent us this video of a school in Bali, called the Green School. It was started by John Hardy, a Canadian who ran a jewelry company with his wife before they embarked on building this environmentally-minded school. It's quite amazing!

Monday, April 7, 2014

Homeschooler gymnastics

San Francisco Homeschoolers organize a gymnastics class on Mondays, which our children love. It is nearby at AcroSports, an edgy gym in a landmark building converted by volunteers from an abandoned pigeon roost.

To see friends, run around, and learn to do flips (if you're E) - what could be better!

Doctors without Borders doctor visit

The children have been interested doctors and their work recently.

This morning we had a visit from our friend Dr. Chris Brasher, a pediatrician who worked for several years in the Congo and starred in the documentary Living in Emergency.

I brought out our globe, and Dr. Chris showed us places he had lived and treated children around the world. He told a story about a five-year-old boy he had treated in Ireland. The boy had challenged him to a bet, wagering one British pound he could tell a joke and make Dr. Chris laugh even as he did a spinal tap on the boy.

Here's how the boy's joke went:

Two cats challenge each other to swim across the English Channel from England to France. One of them is British, and is named One-Two-Three. The other, a French one, is named Un-Deux-Trois.

Which one do you think won the race?

One Two Three cat because Un-Deux-Trois cat sank (un deux trois quatre cinq!)

The Irish boy had won the bet. "He was a tough kid," said Chris.

Tuesday, April 1, 2014

The solar system

It took me a few weeks to prepare a unit on the solar system.

We started by looking at the sun using specially designed kids' welder goggles (do not use regular sunglasses - you can find inexpensive kids' solar eclipse observation glasses on Amazon) and clocked how long it takes for light to travel from the sun to the earth (8 minutes and 20 seconds). This in itself was an exciting exercise. For bigger kids, Khan Academy has a good video on the scale of the earth and the sun.

The most amazing thing about space is how astonishingly vast it is. Yet, despite its immense scale, we can design spaceships and travel in it because we can measure its geometry really accurately. Astronomy is all about the math of distances. I wanted the children to get a feel for that.

There is a whole industry of educational solar system kits out there. But I couldn't find one that was proportionally accurate. So I cobbled up my own model using the following scale, adapted from this Finnish document (it's in meters and centimeters; we've used the metric system for science from the start, and our children are used to it).

PlanetSize (cm)Distance (m)Note
Sun100.00If the diameter of the sun was 1 meter...
Mercury0.443Mercury would be 40 meters from the sun
Venus0.978Venus would be about 80 meters from it
Earth0.9107The earth would be about 100 meters from it and just under 1 cm in diameter
Mars0.5164It would be 160 meters to Mars
Jupiter10.3559It would be 560 meters to Jupiter, which would be 10 cm in diameter
Saturn8.61,0251 kilometer to Saturn, which would be 9 cm in diameter
Uranus3.72,0612 kilometers to Uranus
Neptune3.53,2293 kilometers to Neptune
(Pluto)0.24,237The distance to Pluto would be 4 km and it would be the size of a pinhead

I found a sun roughly the right diameter from this inflatable kit. The smaller, rocky planets were about the right size in a kit similar to this Smithsonian one that I picked up on the sale rack at Lawrence Hall of Science in Berkeley. Since these planets are so small I wanted the surface to look detailed. The bigger gaseous planets were roughly the right size in this unpainted styrofoam kit.

I hung the sun in the school tower room. Cool!

We then painted the larger gaseous planets (the smaller ones from the other kit were already painted). While painting, we talked about what they are made of, and why each one is a different color. And peculiarities like Jupiter's Great Red Spot, and of course Saturn's rings.

We played with them to get a better feel for their relative sizes. Compared to Earth the sun is SO HUGE! The children didn't seem to ever get tired of marching in ellipses to show how they orbit round and round.

Also, by now we had memorized their order.

The next day we went to the beach to measure orbits. While R held the sun up high, the children measured the distance to Uranus, then Venus, then the Earth and Mars using a big outdoor tape measure I had ordered for this purpose.

When we got to the orbit of the Earth (107 meters from the sun) one of the girls exclaimed "it's the same size as the real sun!" Which was true - the real sun, its sphere visible through cloud cover, was the same size as our inflatable one, which R was still holding where we had started. We could easily blot either sun out with our thumb.

After Mars (160 meters) the children had had enough walking. It was humbling to think that we still had another 400 meters to get to Jupiter at the end of the beach. And that sand grain-sized Pluto was whizzing by Point Bonita Lighthouse four kilometers away, on the other side of Golden Gate Bridge.

Later this spring I plan to connect this to our ongoing interest in ancient temples and cultures. Stonehenge, the pyramids, and the Mayan temples all stand testimony to the crucial importance of the celestial bodies to people, their religion and societies throughout history. I'm planning to use the book Celestial Geometry: Understanding the Astronomical Meanings of Ancient Sites as one of the resources for this upcoming unit.