Lesson Seven Surface Area and Absorption

1. Lesson Seven Surface Area and Absorption • Objectives • Calculate the surface area of a cube and rectangular solid • Build a cross-section model of small intestines • Calculate and compare surface area of different folds and relate it to absorption in intestines • Describe the function of the small and large intestines • Bellwork • Why is it easier to get many small twigs to begin burning, rather than one or two large logs?

2. Introduction p 50 SG How do you calculate surface area? (provide rulers and practice calculating the surface area of the desk/book and cube) Problem What is the relationship between an object’s surface area and its ability to absorb? (discuss folding a paper towel as an example) Hypothesis If you _________ an object’s surface area then it will absorb_________ because _____________.

3. Materials 2 clay cubes, ruler, calculator, tickets Procedure 7.1 • Use a ruler to make a clay cube that measure 2cm on each side. • Calculate the surface area of the cube. (2 x 2 x 6) • Change the shape of the cube to increase the surface area. You must be able to calculate the surface area mathematically. • Calculate the surface area of the new shape. Data • Draw the shape of the cube and show your calculations of surface area • Draw the new shape and show your calculations of surface area

4. Procedure 7.2 • Tape a strip of 12 tickets in a circle • Calculate the inside surface area of the circle if one side of the ticket has a surface area of 25 cm2 (25 x 12, be sure to check the book) • Fanfold a strip of 30 tickets, tape and place it inside of the12 ticket circle • Calculate the surface area of the folded strips inside of the circle. (25 x 30, check the book) • Compare the surface area and express as a ratio Data 1. Show your calculations for the surface area of the two strips of tickets. 2. Determine the ratio of the surface area of the two strips of tickets.

5. Reading (Must do reading before answering reflection questions for them to finish conclusion and answer questions) Surface Area: Your Intestine Isn’t Small at All p54 Conclusion Answer the original question Restate the hypothesis Use your calculations to support your answer Next Question

6. Vocabulary surface area feces absorption diarrhea villi constipation microvilli flatulence colon laxative appendix

7. Can discuss as class or assign for homework Reflection Questions • Explain how you can prove you increased surface area. • What are the advantages of the great surface area in the small intestines? What other organs might need this? • Which would dissolve faster in hot water, a sugar cube or a teaspoon of sugar? Explain. ( questions 3-4 are from TM pg 73) • What might we look like if there were no folds in the intestines? • Other things are designed with folds. What is the advantage of folds? • Read Spies- Leftovers pg56-57 (only place lg intestine is discussed) • Explain what happens to water and undigested wastes in the lg intestine. • (May ask for a written summary of the whole digestive process) • Other Homework ideas- Extensions p 74 in TM - all are good Homework