Materials and Equipment

Objectives: The purpose of this lab is to understand how the size of an object can affect the ratio of surface area to volume. Additionally, this lab will lead students to an understanding of how the particle size of a catalyst can alter is effectiveness. An optional extension will guide students in designing an optimal catalyst for a formic acid fuel cell. Materials and Equipment: 1 • 8.5 inch × 11 inch sheet of waxed paper 2 • modeling clay 3 • metric ruler 4 • calipers, with metric markings 5 • pencil 6 • calculator 7 (Note: No special safety instructions for this lab)

Procedure: 1. Students will complete Surface Area and Volume guided inquiry activity provided on the student worksheet. 2. Discuss how results of lab apply to catalysts. Possible discussion questions: a. How do catalysts affect a chemical reaction? b. How do they do this? c. If you had to design a catalyst, what properties would it have? How would you achieve this? 3. Optional Extension: Students will be guided through the design process for a catalyst. They will have to consider everything they learned from the previous activities as well as the cost of the catalyst. A guided discussion worksheet is included in this activity. Surface Area and Volume Student Worksheet Why can spiders walk on the ceiling? Why can airplanes fly? Why do the cells in your body stop growing? All of these questions have to do something with the ration between surface area and volume. In this lab, you will discover how the size of an object can affect the relationship between the surface area and volume. Procedure: 1. Place the wax paper on top your desk. For each of the steps below, be sure to use all of the clay. Do not remove any clay between measurements. 2. Press the clay into a cube. 3. Use the ruler to measure the size of each side. Write each measurement in the table below. 4. Press the clay into a flat, rectangular box. 5. Use the ruler to measure the size of each side. Write each measurement in the table below. 6. Roll the clay into a ball. 7. Use the calipers to measure the ball’s diameter. Write your measurement in the table below. 8. Roll the clay into a cylinder. 9. Use the calipers to measure the diameter of the cylinder. Write your measurement in the table below. 10.Use the ruler to measure the length of the cylinder. Write your measurement in the table below. 11.Roll the clay into two balls. 12.Use the calipers to measure both ball’s diameter. Write your measurement in the table below. 13.For the clay into four cubes. 14.Use the ruler to measure the size of each side of all four cubes. Write each measurement in the table below. 15.Use the accompanying formula sheet to calculate and complete the surface area and volume portions of the data table

Data Table Surface Surface Shape Dim 1 Dim 2 Dim 3 Volume Area/Volu Area me Cube Flat Box

Ball X X

Cylinder X

2 Balls X X

4 Cubes

Analysis: 1. Come up with your own configuration of clay that has a surface area to volume ratio that is greater than that of anything in the lab. Describe it below.

2. How would you form the clay to get the largest surface area to volume ratio possible? Extension: Designing the Optimal Catalyst In this activity, you will play the role of a consultant to a chemical company. They have hired you to design a catalyst which will help make the production of a certain chemical both quicker and more cost effective. A series of discussion questions follows. The questions are designed to help lead you to your recommendation. Your teacher will tell you whether you will be answering these questions in small groups or as a class. 1. What is a catalyst, and in what ways does it effect a chemical reaction?

2. What factors would an industrial chemical company consider when choosing a process for the production of a chemical?

3. Often catalysts are made of precious metals such as platinum or palladium. These metals are very expensive. If a chemical company determined it could afford to purchase 100 grams of platinum which of the following options would you suggest? Why? Justify your anwer. a. 100 grams of platinum in one 5 cubic centimeter sphere b. 100 grams of platinum in five 1 cubic centimeter spheres c. 100 grams of platinum in 500 .01 cubic centimeter spheres 4. Gilding is a process in which wood, stone, or metal is covered with a very thin coating of gold. Why do you think this is done? Why not just make the entire object from gold?

5. Do you think this concept could apply to the design of your catalyst? Consider how a catalyst functions in a chemical reaction.

6. Describe the catalyst you recommend the chemical company use.

BONUS: Describe a chemical process for producing the catalyst. Think about any chemical reactions you have seen in the past.