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chemistry/COMMON CORE: CRITICAL THINKING

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FACT OR OPINION?Read the following sentences related to “Name That Element!” (p. 20). Use the chart below to review what makes a statement a fact or an opinion. Then write an “F” on the line if the statement is a fact and a “O” if the statement is an opinion.

STATEMENTS

_____ 1. It was difficult to determine which element was described in the text.

_____ 2. Silver and copper are electrical conductors.

_____ 3. It’s a good thing I don’t have any false teeth.

_____ 4. An alloy is a metallic mixture.

_____ 5. King Tut’s inner coffin contained 109 kilograms of gold.

_____ 6. Astronauts have a fascinating job.

_____ 7. Particles of gold are our best hope for curing cancer in humans.

_____ 8. Gold has 79 protons in its nucleus.

_____ 9. King Tut was the most important person in ancient Egypt.

_____ 10. Thin layers of gold reflect solar radiation.

FACT OPINION• True statement

• Can be tested or proved

• May contain numbers that can be checked against other sources

• Shows what someone thinks

• May include emotions

• May use words like believe or think

• May contain bias, an attitude for or against something

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BIOLOGY: READING COMPREHENSION

GOLD FROM BACTERIAIn “Name That Element!” (p. 20), you read about the element gold. Read the following passage to learn about a microorganism that can make this valuable element from a poisonous substance. Then use complete sentences to answer the questions that follow.

MINIATURE GOLD FACTORYIn Greek mythology, King Midas turned everything he touched into gold. It turns out a species of

bacteria has the Midas touch: Cupriavidus metallidurans can turn a type of poison into solid gold. A recent art project developed by researchers at Michigan State University showed off the microbe’s amazing ability.

In the exhibit, billions of the bacteria were placed in a special glass tank. They bathed in a solution containing high concentrations of gold chloride, a compound of gold and chlorine atoms. Gold chloride is toxic to most living things, but these bacteria have adapted to withstand it.

The bacteria break down the compound to get the energy they need to live. Then they secrete microscopic bits of gold in its pure, nontoxic form. “Basically, they’re pooping out gold,” says microbiologist Kazem Kashefi.

Scientists think bacteria with similar abilities may help gold nuggets form in nature. Examinations of gold-containing rocks have revealed films of the bacteria living on the gold. No one will get rich harvesting golden bacterial poop at home, though. Kashefi says the cost of running the project was higher than the value of the gold it produced.

QUESTIONS1. What is the central idea of this passage?

2. Why did the author say Cupriavidus metallidurans bacteria have the Midas touch?

3. What is another unusual characteristic of C. metallidurans?

4. What is one reason that scientists believe bacteria like C. metallidurans may help form gold nuggets in nature?

5. Why do you think scientists created an art project based on C. metallidurans?

ANALYZE IT1. On which continent is the country with the largest gold reserve base located?

2. What is the total gold reserve base of the top-five countries?

3. How many times larger is the gold reserve base of South Africa than that of the United States?

4. The total gold reserve base for the world is estimated to be 100,000 metric tons. What percentage of that is located in South Africa?

5. Gold reserves are the part of the reserve base that could be mined at a profit using today’s technology. The gold reserves of the United States total 3,000 metric tons. What percentage of the gold reserve base would be too expensive to mine profitably today?

GRAPH ITOn a separate piece of paper, use the data in the chart to create a bar graph showing the gold reserve base of the countries shown. Be sure to label the x- and y-axes and give your graph a title.

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EARTH SCIENCE: GRAPHING

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WHERE’S THE GOLD?In “Name That Element!” (p. 20), you learned about the element gold. The table below shows the five countries that have the largest amount of gold buried beneath the surface. The chart shows each country’s gold reserve base, or the total amount of gold that could potentially be mined. Use the data in the chart to answer the questions that follow.

CountryGold Reserve

Base (metric tons)

South Africa 31,000

Russia 7,000

Australia 6,000

Indonesia 6,000

United States 5,500(U.S. GeoloGiCal SUrvey, Mineral CoMModity SUMMarieS, JANUARy 2012)

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physics: READING COMPREHENSION

HIGH-TECH GOLDIn “Name That Element!” (p. 20), you learned about uses of the element gold. Read the following passage to discover why this element is so important in electronics. Then answer the questions that follow.

ELECTRIC ELEMENTyou may think of gold mainly as a material for jewelry. But in 2012, more than 300 tons of gold

were used to build new electronics.

Gold is highly conductive, which means that even small electric currents flow through it easily. And unlike other elements that corrode and lose their conductivity, gold is unreactive and holds up well over time. The element is commonly used at connection points between electric circuits in devices like computers and cell phones. Without the right material, these points where two metals meet can become hot spots for corrosion.

Someday, a new type of gold conductor may even be implanted inside humans. Scientists have recently developed a stretchy material made of gold nanoparticles embedded in flexible plastic. Normally, stretching causes materials to lose much of their conductivity. But the new material can still conduct an electric current after being pulled to four times its original length.

Scientists say the material could be especially useful in medicine. For example, it might be used in a pacemaker for the heart. Because of its flexibility, the material would cause less scarring and damage to surrounding tissue.

QUESTIONS1. A material that can carry an electric current is best described as ____.A unreactiveB corrosiveC reactiveD conductive

2. Which of the following is NOT true about gold?A It can carry an electric current.B It is found in electronics.C It corrodes easily.D It doesn’t react easily.

3. According to the passage, why might the new stretchy gold material be useful in medicine?A It could carry an electric current without reacting with

the body.B Its flexibility would mean less damage to surrounding

tissue.C It would contain less toxic material than conductors

made of other metals.D The gold conductor could be used to make very small

parts.

4. Which of the following BEST describes the author’s main purpose in writing this passage?A to explain why gold is an important element in

electronicsB to describe a new stretchy material made of goldC to persuade readers to buy more electronicsD to provide readers with statistics about gold

5. Every year, tens of millions of cell phones and other electronics are thrown away and dumped in landfills instead of being recycled. Do you think this is a good outcome? Support your answer with facts from the passage.