For many people, cookouts are an occasion for friends and family to gather and enjoy a meal outdoors. When planning a cookout, people may gather a wide variety of materials, but one of the most commonly used is charcoal. This light, dusty material resembling small black rocks is useful for building hot, long–burning fires. Charcoal has many additional uses as well. Many people use charcoal, but few know where this unusual rock–like material comes from.

Question

The Science Behind Charcoal

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Although charcoal resembles stone, it is usually made from wood. Wood is primarily composed of three elements: oxygen, hydrogen, and carbon. Carbon is the element needed for charcoal. Over hundreds of years, people have perfected ways to extract carbon from the wood, but this process can be challenging.

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In a regular fire, all three elements in wood burn quickly, leaving behind ash. The useful carbon is mostly ruined. In order to make charcoal, people have to find ways to burn only the oxygen and hydrogen in the wood and leave behind the valuable carbon. The best way to do this is burning wood slowly while keeping the fire away from open air.

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Some charcoal may also be made from discarded animal bones. Bone charcoal, also known as bone black, is produced by a technique similar to that used for wood charcoal. The bones must be heated in a sealed container to remove any oil, water, or other non-carbon material to leave behind only the carbon.

The History of Charcoal

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People have been creating charcoal for hundreds of years. In medieval times, many villages had people who became experts at creating charcoal. These experts would begin by stacking wood into round piles shaped like cones. Within these piles were open chambers to allow smoke to exit, like small volcanoes. Workers would cover these woodpiles with wet dirt and grass that would seal in heat when burned. It was a primitive system, but it worked.

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The cone-shaped pile would burn slowly for many hours or days and then cool slowly as well. By the time the fire was completely finished, much of the wood was converted into charcoal. However, even more of the wood was ruined in this process. If a worker used one hundred pounds of wood, he or she would most likely only produce about twenty pounds of charcoal. People had to cut down many trees to feed these wasteful fires. The production of charcoal led to deforestation in some parts of the world.

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The completed charcoal, however, was a cherished resource. People could use it for heating or cooking, but it was mostly used by blacksmiths. Charcoal fires could reach high temperatures and melt metal, allowing blacksmiths to forge tools, weapons, and armor. Later, people used charcoal in foundries to melt and form large quantities of metal. Other people discovered uses for charcoal in chemistry and medicine, and artists used it as pigment in colorful paints.

Charcoal in Modern Times

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Charcoal is still important in the modern world, but people have found more efficient ways of creating it. Most wood charcoal today is produced in closed ovens. People today get more charcoal from the wood they use and are also able to extract other valuable byproducts from the wood. This makes the process less wasteful of natural resources.

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Today, charcoal is no longer common as an industrial fuel for melting metal or other such purposes. Rather, modern people most often use charcoal for cooking and cleaning. Charcoal intended for cooking is most often combined with other flammable materials and turned into small rocks called briquettes. Briquettes are easy to ignite and burn with high heat and little smoke, perfect conditions for cooking.

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Though charcoal is best known for its qualities of combustion, it is not always associated with fire. Charcoal is often used for cleaning and filtration. Charcoal has many tiny holes in it, and its porous nature allows it to grip solids and gases alike. Many people use charcoal for water filtration because the charcoal will hold onto impurities from the water. Charcoal is also important in absorbing gases and odors from the air, and may be used in filters on breathing masks. Although an ancient material, charcoal remains extremely useful in the modern world.

Read this sentence from the text.

Within these piles were open chambers to allow smoke to exit, like small volcanoes.

The author most likely included the analogy "like small volcanoes" Query
.

Answer 1

to help readers visualize the shape and function of the cone-shaped wood piles used in the charcoal-making process. By comparing the structure to small volcanoes, the author conveys the idea that, just as a volcano allows gases (in this case, smoke) to escape while containing the heat inside, the open chambers in the wood piles serve a similar purpose, helping to facilitate the release of smoke while enabling the slow burning of the wood to convert it into charcoal. This analogy adds a relatable image that enhances the reader's understanding of the technique used historically to produce charcoal.

Answer 2

Options:
A. To help readers create a mental image of the pile
B. To show differences between nature and industry
C. To suggest that the piles were extremely dangerous
D. To demonstrate the great size of the burning piles

Answer 3

The best option is:

A. To help readers create a mental image of the pile

This option aligns with the purpose of the analogy, which is to provide readers with a relatable reference to better understand the shape and function of the wood piles used in the charcoal-making process.

Answer 4

A student is writing an article for her club flyer. The student wants to revise the draft to add transitions in order to make the text more clear and coherent. Read the draft of the article and complete the task that follows.

Last September, the marine biology club had a bake sale, car wash, and book fair. The department chair was very proud of the students' efforts to raise funds. __________, their fundraising efforts, the marine biology club did not raise enough money to go on a group trip. __________, all of the students were extremely disappointed.

This year, the president of the marine biology club hopes for a better turnout at the fundraising events. It is really important to earn enough funds in order to send the students on the scuba diving trip they have all been planning on. Please make sure to invite all family and friends to support the marine biology club's efforts this year.

Choose the best transition for each of the blank spaces that would clarify the relationship between the two underlined sentences. Select two that apply.
A.
In spite of

B.
Consequently

C.
For example

D.
In addition

E.
In contrast

F.
In essence

Answer 5

The best transitions to fill in the blanks are:

1. A. In spite of - This transition clarifies that despite the students' efforts to raise funds, they did not achieve their goal.

2. B. Consequently - This transition indicates that as a result of not raising enough funds, the students were disappointed.

So the completed sentences would read:

"In spite of their fundraising efforts, the marine biology club did not raise enough money to go on a group trip. Consequently, all of the students were extremely disappointed."

Answer 6

A student is writing a social studies report for class. Read the paragraph from the student report and answer the question that follows.

After the Louisiana Purchase, the territory of the United States increased by a lot. The land gained stretched from the Mississippi River to the Rocky Mountains and from the border of Canada to the Gulf of Mexico, and meant that the Unites States controlled twice as much territory as it did before 1803. The purchase was an important achievement of President Jefferson.

The student wants to replace the underlined phrase with something more precise. Which replacement BEST fits the author’s intended purpose and audience?

A.
was added to

B.
became much bigger

C.
grew

D.
doubled

Answer 7

The replacement that BEST fits the author’s intended purpose and audience is:

D. doubled

This option is precise and conveys the significant increase in territory as a specific, measurable change, which aligns well with the informative nature of the report.