Investigation 7.2 Worksheet
The first thing to make sure you remember is how to calculate surface area. If you aren't sure, Google the procedure and practice it a little. You will need to remember how to calculate surface area to perform the investigation.If you do not have raffle tickets to use as a model, do this instead: fold a piece of paper in half lengthwise, then one more time lengthwise. Unfold it, and use scissors to cut the paper into strips on the folds, so you have four paper strips. Tape the short ends of one of the strips together to make a circle shape. This isn't accurate, but let's assume that the length of the paper strip is 28 cm, and the width is 5 cm. (This will make calculations easier.) What would the surface area of the inside of your circle work out to be?
Now, tape two strips of paper together on their short ends, to make a longer strip of paper. Fold it in half lengthwise, where you taped it. Then fold it in half again, then again, however you want to fold it fairly evenly so when you are done, you have 16 sections. Unfold it, and refold on the fold lines in a zigzag, "accordion" pattern. Now tape the ends of the strip together, and you should have something that looks like the star pattern you see in the upper diagram, and it should be able to fit inside your original circle.
Now, let's assume for a moment that each section of the folded paper is still 5 cm wide, but the sections are now 3.5 cm long. If there are 16 of these sections, what would the new surface area work out to be?
The important things to understand about the investigation are how the raffle tickets represent the inner lining of the small intestine, how the folds help to increase surface area, and why the increased surface area of the lining of the small intestine is important to absorption and digestion. The reading in Lesson 7 on surface area does a good job of bringing it all together! Let us know if you have any questions!
