Additional Math Pages & Resources

Wednesday, September 8, 2010

Distances, Part II

This blog  talks about how adults use the concepts and skills we learn in elementary math class.

Distance is not the same as length or width. Those are dimensional measurements of an object. In contrast, distance is the measurement of a route between two points (not always the shortest one).

In normal conversation, we often use vague distance terms, as in "I live a mile from the water."

We had a little rivalry in the office recently. One of us claims to live right near the ocean. I live close to the water too, and I thought I might live closer than she did. A major street runs north and south in our area of town. She lives east of it; I live west of it. The ocean is west, so I must be closer, right? But we couldn't agree, so we had to make some objective measurements of the distances.

This is a process of measuring known as the crow flies (or in our case as the seagull flies).

What we mean is in a straight line, not how you would have to go via the streets. Normally you would do this measurement using a map and a ruler, or perhaps with a compass to draw a circle around the point where you live. But yesterday I found that Google Maps has a new feature to helps you with this distance measuring business. You click on two points and it shows the distance between them.

Here's the first measurement - from the house of my co-worker to the ocean, approx. 1.42 miles
This is an alternative measurement, to the bay instead of the ocean. Only 4208 feet

This route is exactly a mile. This body of water is also part of the bay, but it's closer to the ocean.

Now let's move to my location. Here's the measurement to the ocean from my place. Boo. It's 1.92 miles. I'm clearly farther away.

But there's a much closer route to salt water. Only 3839 feet to San Diego river - salty at this point!
Then I found an even closer source of water. Just 3113 feet to the waterway to the south.

Finally, to give you a better perspective on all this water, here's an overview from higher up. The red line shows the 4.14 mile distance from one house to the other. The blue line is the street that runs between our houses. I had not realized it turned eastward so dramatically after it crosses the river. The two yellow circles are the same size at 1.5 miles radius, or 3 miles diameter. She's closer to the water.

The ironic thing about this is that we were not bragging about being close to the beach. We were trying to out-complain each other about our dreary Labor Day Monday. As in We couldn't see a thing because we are so close to the beach; the marine layer blocked the sun all day! Whine, whine, whine.