UNIT 8 · LESSON 4 + REVIEW

Discuss the Impact of Inventions / Discoveries

Interactive lesson about antibiotics, inventions, discoveries, review vocabulary, and conditional sentences.

By the end of this lesson, students can:

  • explain the impact of antibiotics and other discoveries.
  • understand key reading vocabulary from context.
  • review technology adjectives and conditional sentences.
  • listen for details and choose accurate answers.
Progress
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Lesson Reference Pages

Open these only when you want to check the original lesson pages.

Open / close Lesson 4 pageUnit 8 Lesson 4 reference page
Open / close Unit 8 Review pageUnit 8 Review reference page

Lesson Beginning · Warm-up

Think about inventions and discoveries that changed people’s lives. Medical discoveries are especially important because they can save lives.

Which discovery is connected to medicine?
What is the main idea of this lesson?
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Reading · Antibiotics

Audio 32 · Reading
Listen and follow the reading about antibiotics.

Antibiotics

Today, vaccines can prevent some of the infectious diseases that in the past resulted in serious illness and death. Fortunately, for diseases caused by bacteria (tiny organisms that can only be seen by microscope), vaccines can make the difference between life and death.

What are antibiotics?

Antibiotics are substances that work in one of two ways. Some antibiotics, such as penicillin, kill disease-causing bacteria. Others, such as tetracycline, stop them from multiplying.

History

In 1675, Dutch scientist Antonie Van Leeuwenhoek, using a microscope, discovered the existence of microorganisms. However, it wasn’t known that they could cause diseases until French scientist Louis Pasteur confirmed that approximately 200 years later. Finally, in 1928, British scientist Alexander Fleming noticed that a mold, penicillin, growing in one of his petri dishes, was capable of killing bacteria, and the development of antibiotics became possible. Fleming named the active agent in the mold “penicillin” but was unable to create a drug from it.

In 1940, during the Second World War, two scientists working at Oxford University, Ernst Chain and Howard Florey, were able to make an antibacterial powder from penicillin that was safe to use on humans. Penicillin was mass-produced for use on soldiers in the war. If there had been no penicillin, many would have died from bacterial infections caused by their injuries and wounds.

Soon penicillin was used for serious diseases such as pneumonia and tuberculosis, which had always caused many deaths. Fleming, Florey, and Chain received the Nobel Prize in 1945. Antibiotics changed medicine and continue today to enable people to survive conditions that would have killed them before the antibiotic age.

Overuse of antibiotics

Since their discovery and widespread use, antibiotics have been considered a wonder drug. Many common diseases, however, are caused by viruses, not bacteria, and antibiotics are not effective against them. Nevertheless, too many people use antibiotics regularly, believing they will cure viral illnesses such as common upper respiratory infections, colds, and sore throats. Why is this a problem?

First, it is a waste of money to use antibiotics to treat viruses. Our body’s immune system eventually combats most viruses, and we recover without treatment. But more importantly, bacteria exposed to an antibiotic can become resistant to it, making the antibiotic less effective, or even useless. If antibiotics no longer work against infectious diseases, people will begin to die from them again.

If scientists had recognized that bacteria could develop resistance, perhaps they would have warned doctors not to use antibiotics unless a patient has a bacterial infection. Hopefully, worldwide awareness of this threat to an important class of drugs will convince us to avoid using them for conditions that don’t require them.

Read the full text first. Then answer the supporting-detail and context questions below.

Find Supporting Details

What can antibiotics do?
Which antibiotic became known as a “wonder drug”?
Why are antibiotics not effective against the common cold?
Why can antibiotics be effective against strep throat?
What problem has overuse of antibiotics caused?
When should patients use antibiotics?
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Understand from Context

Choose the correct word to complete each sentence.

1. A ______ prevents diseases from occurring.
2. ______ can cause infectious diseases.
3. Bacteria are small organisms that can only be seen ______.
4. ______ is a drug that kills bacteria.
5. The common cold and influenza are common ______ infections.
6. Some antibiotics are no longer effective because bacteria have developed ______.
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Now You Can · Discuss Impact

What did the plow help farmers do?
What did the printing press make possible?
What does the zipper help people do?
Which sentence uses the past unreal conditional correctly?
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Unit Review · Listening and Grammar

Audio 33 · Review Listening
Listen and answer the review questions.

Review A · Match the Product and Adjective

1. The Ultraphone is...
2. Dinner-from-a-distance is...
3. Kinder-TV is...
4. Ten Years Off is...

Review B · Choose the True Statement

1. We wouldn’t have gotten lost if we had remembered to bring our portable GPS device.
2. If the salesclerk were here, she would explain how the Omni works.
3. If Ron had brought the Ultraphone with him, he would have already sent those e-mails.

Review C · Conditional Sentences

If the computer hadn’t been invented, ...
If I had to decide what the most important scientific discovery in history was, ...
If most people cared about the environment, ...
If gasoline, heating oil, and fossil-fuel products become scarce, ...
If I could invent an inexpensive yet innovative low-tech solution to a problem, ...

Final Quiz

1. Which word means “a drug that kills bacteria”?
2. Which word means bacteria can survive antibiotics?
3. Choose the correct conditional sentence.
4. Which invention helped people print many books?
5. Antibiotics should not be used for...

Amazing!

You’ve completed Unit 8 Lesson 4 and Review.