Teaching Notes

For the students to successfully assemble the image in For You To Do Steps 1 through 4, they must begin properly, with the upper left pixel in their group of four rows of pixels in the image. Remember that four rows of pixels correspond to three rows of ones and zeros. When they reach the end of the first row (the top right pixel), they must “return” to the next row down, all the way to the left. Help them set up their graph paper and number it properly, as explained in Step 2. See the For You To Do at the end of Activity 7. The students examine the fax with a magnifier in Step 6, but they probably will be unable to see individual pixels. When faxes first became popular, it was possible to examine the image with a magnifier and see the individual pixels clearly. As technology advanced, the pixels became smaller and the image correspondingly more sharp and clear. Today a magnifier reveals only a suggestion of the pixels.

See the end of Background Information for notes on how the rows of data on page 286 correspond to rows of the image on page 287. You can assign a group of three rows to one group of students. These three rows of data will become four consecutive rows of the image. It might help to place a small mark every four rows on the graph paper. The students will cut out their part of the image, and you can paste their part into the corresponding rows (so be sure you can match the rows of data to the rows of the image).