Lab #5

Tradeoffs in the extraction of minerals and ores from the crust

Name______Class______

Partner______Date______

You must have read pages 85-103 (Chapter 6)

Introduction

Supplies of valuable natural resources are diminishing rapidly. The world supply of essential minerals, for example, is limited. Energy resources, such as coal, petroleum and natural gas are also limited. As these resources dwindle, scientists search for new, renewable, and alternative resources.

Purpose

Students will be able to explain and describe the major tradeoffs involved in the mining of minerals from the earth.

Materials

2 cookies (1 regular and 1 chocolate lovers)

1 toothpick

2 to 3 napkins

1 triple beam balance

Procedure A (questions)

1)  Answer the following questions in complete sentences ( Put into conclusion section)

a)  If your cookie represents the earth’s crust, what might the chocolate chips represent?

b)  In comparing your two cookies, what differences are immediately available?

c)  How might these differences to the earth’s resources (e.g. aluminum, iron, coal, etc.)?

d)  Are the chips a renewable resource? Why or why not?

Procedure B (Mining the cookies)

2)  Rip the napkin into two pieces

3)  Place one part of the napkin on the triple beam balance, then place the regular chocolate chip cookie on the top of the napkin on the triple beam balance. Record the mass of the cookie in the table provided to the nearest tenth of a gram.

4)  Take the cookie off the scale and place it on your table.

5)  You will now be given 1 minute to extract the chocolate chips from the cookie, if you do not get them all it is ok you will be given four more trials to do so.

6)  Place the chocolate chips on a napkin and put it on the triple beam balance. Record the mass of the chocolate chips in the table provided to the nearest tenth of a gram.

7)  Repeat steps 3 through 5 and record the information in the table provided 4 more times.

8)  You will now do steps 2 through 5 for the chocolate lovers cookie. Please record all values in the data table provided.

Data and observations

Regular chocolate chip cookie

Time (minutes) / Mass of cookie(grams) / Mass of chocolate chips (grams) / Percentage of chocolate chips mined (%) / Condition of cookie
00:01:00
00:02:00
00:03:00
00:04:00
00:05:00

Chocolate lovers cookie

Time (minutes) / Mass of cookie(grams) / Mass of chocolate chips (grams) / Percentage of chocolate chips mined (%) / Condition of cookie
00:01:00
00:02:00
00:03:00
00:04:00
00:05:00

Using the following information create a graph of aluminum content of Ore (%) versus the energy needed to extract 1 ton of Aluminum (Thousands of kilowatt-hours)

Aluminum %- Independent variable

Energy needed- Dependent variable

Sample / Aluminum content of ore (%) / Energy needed to extract 1 ton of aluminum (thousand of kilowatt-hours)
1 / 3 / 220
2 / 5 / 140
3 / 10 / 90
4 / 20 / 65
5 / 30 / 54
6 / 40 / 49
7 / 50 / 48

Conclusion

1)  If the chips are the most important part, and you consume all of your chips, how might you obtain more chips?

2)  Examine your cookie remains. How is your chocolate chip “mining” similar to actual mining?

3)  How is your chocolate chip “mining” different from actual mining?

4)  What happened the amount of chips that you were able to extract with the passage of each 1 minute time interval?

5)  What happened to the condition of your cookie with the passage of each 1 minute interval?

6)  Each year we must discover more remote and less concentrated deposits of earth materials. Why?

7)  What are some tradeoffs involved in mining?

8)  How does recycling metals, glass and plastics help reduce some of these difficult choices (from above) facing society?

9)  If you desire you may eat your cookie and chocolate chips. Are the chips more like metallic resources (aluminum, iron, copper, etc.) or like fossil fuels (coal)? Why?

10) According to the graph you constructed, how much energy is needed to produce aluminum from rock that is 15% aluminum? How did you find this? Express your answer in thousands of kilowatt-hours

11) Using one or more complete sentences, describe how the amount of aluminum in a rock is related to the amount of energy needed to extract the aluminum from the rock. What type of relationship is shown?

12) At which time interval will the most energy be needed to extract 1 ton of chocolate chips? Refer to the information graphed to obtain answer.

13) In a one page summary explain any sources of errors that may have occurred and what you could do to modify the lab to make these corrections.