Printing With Fruitography

Starring

You and Your Students!

Script By

Vicki Cobb, Education World Science Editor

Synopsis

Develop a photograph on an apple!

Genre

Biology

Required Props

• green apple on a tree
• lightproof bag (for example, a potato chip bag)
• photo negative (color or black and white)
• egg white
• scissors
• tape

Setting the Scene (Background)

The school year is winding down, so I thought you might enjoy a project to begin next year with a fascinating oddity -- an apple with your picture developed on the skin in red and green! Some of your students might like to try it as well.

Stage Direction

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You might introduce this project with a discussion of what fruits and vegetables need to ripen. (They need water, fertilizer, and, most important, sunlight.) What happens if you prevent sun from reaching the skin of an apple? Will the skin of the apple turn red? If it doesn't turn red, but remains green, can you produce a pattern on the apple? If so, why not produce an image? A photographic negative not only produces a pattern -- it can reproduce a picture!

Plot

Select a full-sized but still-green apple from a tree. Don't pick it!

Note: "Fruitography" doesn't work on Granny Smith or Golden Delicious apples. There is not enough color change in those varieties to make a print.

• While the apple is still on the tree, enclose it in a light-proof bag. (A foil-lined bag used for take-out chicken or an empty potato chip bag will work well.) Leave the bag on the apple for a week. Doing this will make the apple particularly light-sensitive.
• At the end of the week, remove the bag and use a beaten egg white to "glue" your photographic negative onto the apple.
• Cut a hole in the bag the size and shape of the negative. Put the bag back on the apple. Tape the bag so the negative shows through the hole. Wait another week.
• When you take off the bag and the negative, your image will appear in red on a pale green background!

Behind the Scenes

During the ripening process, fruit becomes softer, sweeter, and tastier -- and it changes color to advertise its deliciousness. Light plays a role in the development of the apple's red pigment, called anthocyanin. The transparent parts of the negative let light through and the color develops. The dark parts of the negative keep the apple skin from receiving light; those parts of the skin remain green.

The End

We've heard that some fruitographers have used tomatoes, eggplants, pumpkins, and squash for their portraits. Your summer garden can produce personalized fruits and vegetables!

Article By Vicki Cobb
Education World®
Copyright © 2005 Education World