KidBridges

ENTRY 1

Today we learned about linear perspective. It's probably the best thing we've learned all year.

This all started when we were talking in our groups about the trip we are going to take to the Brooklyn Bridge. Edward, in my group,

was wondering where on the bridge does New York City start? He thought that it was Brooklyn all the way to the end of the bridge, but Ms. T. says that Brooklyn was already in New York City. Edward just said "oops" he wasn't even embarrassed.

Yes, Brooklyn is one of the 5 boroughs of New York City. It became part of New York City in 1898. Manhattan is another borough. The other three are the Bronx, Queens, and Staten Island.

Ms. T.

Ms. T. gave us a map

of New York City. She showed us how Manhattan starts in the middle of the river, so once we walk about halfway across the bridge, we'll be in Manhattan.

The scale of the map is 1"= 1.4 miles. I figured out

that our school is 3" from the Brooklyn Bridge on the map, so that is equal to 3 x 1.4 miles = 5.2 miles. So the school is 5.2 miles from the bridge. I guess we better take the subway!

We scanned the map

into the computer, so we could always look at it and know where we are.

If the East River is ½" wide on your map, then how far will we be walking when we cross the Brooklyn Bridge?

Ms. T.

Anyhow, perspective.

Ms. T. explained that the physical world has 3 dimensions: height, width, and depth, but our eyes just have a flat 2D screen like a TV or a computer screen to see with. The screen that's part of our eyes is called a retina, and it's 2D, but our brain figures out how to make the world look 3D, like it is.

Good! When you stand in Brooklyn and try to figure out how far away the Manhattan bank of the river is, you'll need 3D thinking.

Ms. T.

Everything follows the rules of math, so your brain can calculate how far away someone is from you by how much their size seems to change. And Ms. T. told us a lot of other ways that things look different when they're farther away. She gave us a whole list of them. They're called depth cues.

Here comes the good part. When you want to draw something that's 3D, like the Brooklyn Bridge and the Manhattan skyline, you can use the rules of linear perspective

to make what you draw on a flat piece of paper look like the real 3D world. You use geometry to fool your own brain!

So, when our group had to come up with a question to answer when we walked across the Brooklyn Bridge, here's what we thought up:

How can we draw the Brooklyn Bridge to make it look right?

We liked that question because it meant that we get to make drawings on the bridge. Ms. T. liked it because we'll have to do some geometry to make our drawings. We'll have to learn about horizon lines and vanishing points, and a whole lot of things like that.

The next step is to go to the bridge and try and draw exactly what we see. When we stop to make a sketch, we'll take a photo in exactly the same place. Then we can compare the drawings to the photos.

Before we go, let's look for some photos and drawings of the Brooklyn Bridge on the web. We can see how many examples of linear perspective and other depth cues we can find in these images.

Ms. T.

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