Scientific Notation

Renata posted in her blog about this fun animation she found about the scale of the universe.

She wanted the kids to understand what was actually going on with the numbers, so we spent most of last week talking about scientific notation and what it really means to multiply by 10.

Using exclamation points as units, here's 1:

!

Here's 10:

!!!!!!!!!!

And here's 100:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Each time we multiply by 10, we really get a lot more stuff!

Scientific notation uses these facts:

10^0=1

10^1=10

10^2=100

10^(-1)=.1

10^(-2)=.01

With scientific notation, instead of writing a distance as

320 meters

we would write it as

3.2 x 10^2 meters.

This helps us get a sense of how big (or small) things really are, in relation to distances we have some sort of feel for. 2 meters is relatively easy to think about. 20 meters might be a little harder to think about - but 20 meters is really 2 x 10^1 meters, which is 2 meters repeated 10 times.

We had a great time measuring out our own scale of the universe on the sidewalk, and filling in things like the length of our math class (with and without teachers).

Here's Stanley writing the scientific notation:

10^(-1) and 10^(-2) are pretty small!

More Partitions

Last week I visited Mrs. Carpenter's class and we played the partition game I did with Elaine's class in January. If we have 5 kids, what are the different ways we can group them?

5=4+1=3+2=2+2+1=1+1+1+1+1=2+1+1+1=3+1+1

Measuring Elaine's Classroom

On Tuesday, I was with Elaine's class. They've been working on measuring - gallons, quarts, pints, cups, etc.. I decided to do something a little more physical: using parts of ourselves as the measuring tools. We measured tables in handlengths (learning the word "perimeter" as we did so), the length of the room in foot-lengths, and the length of the room in person-lengths!

For the last one, we worked in pairs. One person laid down on the floor, and the other held a ruler to mark where their head had been, so the lying-down person could get up and lie down again with their feet where their head had been. I'm sorry I don't have pictures, but I was sort of busy helping remember numbers and measuring the room myself! For most of the kids, the room was about 7 kid-lengths. The room was only about 5 Jesse-lengths.

Mathematical Bagels

Earlier this year, Joanna sent me a link to a page that explains how to construct a mathematically correct breakfast. With careful cutting, one can turn a bagel into two linked bagel halves!

The activity as described involves drawing on a bagel with a permanent marker. Unfortunately, if you do that you can't eat the bagel. I figured that by now there must be such a thing as edible markers, so I went hunting online and found some. With the aid of food markers, last Thursday we set about bagel-ing.

Most of the kids *almost* got it to work, but had one half that was just a little too thin and broke. We'll try this activity again later in the semester.

The quote of the day, possibly of the year, was from Alec: "The only thing better than food is math that is food."

Step 1: Meet the bagels, and decide which side is the "front."

Step 2: Draw on the bagels.

Step 3: Cut the bagels.

Ta-da!

(This one is mine:)