Unplugged - 2nd grade

[Don B]

I recently had the opportunity to talk about programming as a career
with my younger son’s second grade class.

I did a similar talk with my older son’s class a few years ago, and
during that presentation I told them about algorithms (instructions).
I told them that programmers write instructions for a computer to
follow, and that my job was to make these instructions as complete and
error-free as possible. I showed them a simplified example of the
instructions to sort a group of numbers. I had a foam board with
numbers pinned to the side, and a large poster board with the sorting
instructions. The instructions were something like:

1) Find the smallest number on the left side of the board.
2) Move it to the next available space on the right side of the board
3) Go back to step 1

They were written more clearly than that, but that was the basic
idea. My son helped move the numbers from one side of the board to
the other as we followed the instructions. That evening, he told me
that his friends and he thought my presentation was boring. (Second
graders are a little too honest.)

Since I found Unplugged, I have looked into some of the materials,
hoping to find something a little more dynamic for elementary kids,
but most of them seem too complicated for second graders. Also, I
only had 30 minutes to talk to them, and there wasn’t time to put
together class exercises, etc.

I decided to make things a little more fun and talk at a level that
was appropriate for the class.

I brought in a box of toys and other items from around the house.
These included an iPod touch, electronic keyboard, a magazine,
Nintendo DS, a stuffed toy that talks when you squeeze it, a pen, a
calculator, and a toy car.

When I held up each item, I asked the students if the item had a
computer in it . if they said yes, I asked them what the computer
did. A few items, like the electronic keyboard, confused them - most
thought it did not have a computer in it. They understood that the
BlackBerry and iPod had a computer, and they were not sure about the
stuffed toy that talked. The toy car didn’t have a computer in it,
but we talked about a real car, which has numerous computers in it – I
asked them what kind of computers were in a car, and they knew some of
them -radio, GPS system, etc. I also said there were other computers
as well that kept the car running, such as fuel injection control. I
think it was important that I brought in things that did not have a
computer in them to create a contrast.

At that point I told them a little about input and output from a
program. A program has three parts: input, instructions, and output.
A program acts on the input by following some instructions, then
outputs something to the user as a result. (This is a very simplified
explanation, of course, but it works for this scenario.)

We talked about a calculator – input is the numbers and the operator,
and when the equal sign is pressed, instructions execute. The output
(result) is shown on the screen. With this in mind, I brought out
the other items from the box and we talked about the input to each of
them, what instructions they might execute inside, and what the output
is.

We listed our inputs:
Mouse click
Keyboard typing
Touch screen
Voice
A signal from a cell phone tower that tells the phone it’s receiving
a call
A motion that causes an accelerometer to act on the current display
(such as turning an iPod touch on its side)
A camera that tracks the eye motion of a physically handicapped
user, and moves the mouse pointer in response.
A computer that acts when a timer goes off, such as an alarm clock.
In this case, the input to one program is controlled by another
program.
Etc.

Then we listed the outputs we could think of:
Screen changes
Sounds
Program changes (a menu selection changes what the program is doing,
or closed the program, etc.)
Sometimes no output means we did something right (we didn’t get an
error message)
A mouse pointer may change to an hourglass to tell us something is
happening.
A signal out of a phone, telling the cell phone network that it is
making a call.
Etc.

I had a lot of fun, and I think this time the kids had fun too. I
could tell that some of the kids never thought of these toys and
devices containing computers, they just think of a Mac or a PC as a
computer. Now they see these things differently, and I hope they will
start to think of inputs and outputs when they use one.