Main Ideas

There is a difference between the topic of a passage and the main idea. Basically the main idea is what the writer thinks about the topic. Sometimes a topic can be described in a word or a short phrase, but the main idea usually needs a sentence to explain it. Sometimes the topic sentence of a paragraph will also give you the main idea, but very often it won't. Look at paragraph A) below.

A) The Haber Process, which was patented in 1908 and commercialized two years later, was one of the most important scientific discoveries of the twentieth century. In this process the natural abundance of nitrogen in the air is exploited to ultimately produce nitrates for use as fertilizer. The key to the process is the passing of nitrogen and hydrogen gases over an iron catalyst and the use of aluminium oxide and potassium oxide as promoters. Unfortunately, German access to this process enabled them to continue fighting in World War I, long after their supply of natural nitrates had been exhausted.

The topic of this paragraph is the Haber Process. What does the writer say about this topic? Well, he says that it was a very important discovery and that it led to World War I being prolonged. That is the main idea. So...
Topic: The Haber Process
Main Idea: The Haber Process led to World War I lasting longer than it should have.

Now if the paragraph about the Haber Process had been written differently, it would have easier to see the main idea. Look at paragraph B) below. It is paragraph A) rewritten another way.
B) The Haber Process enabled the Germans to continue fighting in World War I, long after their supply of natural nitrates had been exhausted. One of the most important scientific discoveries of the twentieth century, this process  was patented in 1908 and commercialized two years later. In the Haber Process the natural abundance of nitrogen in the air is exploited to ultimately produce nitrates for use as fertilizer. The key to the process is the passing of nitrogen and hydrogen gases over an iron catalyst and the use of aluminium oxide and potassium oxide as promoters.
It is much easier, isn't it? Unfortunately, not everyone writes in paragraphs of a standard. simple form.

Task 1: Read paragraph C) . The topic is the early histroy of flight. What is the main idea? Discuss in groups.
C) By the latter part of the 19th century, Otto Lilienthal in Germany and Sir George Caley in England had made a series of successful short flights in gliders and made the first important steps in the gathering of aeronautical knowledge. However, it was not until the Wright brothers flew their biplane machine off the sands of Kittyhawk, North Carolina in 1903, that the dream of powered flight became a reality. Things then started to move quickly. In 1909, the Frenchman Louis Bleriot made the historic first flight from France to England. A mere ten years later, two Englishmen, Alcock and Brown, succeeded in making the first non-stop flight across the vast spaces of the Atlantic Ocean.
Main idea __________________

Task 2: Read paragraph D) . What is the topic?. What is the main idea? Discuss in groups.
D) The native peoples of Greenland and Canada’s northern regions traditionally often lived in a type of snowhouse known as an igloo. There were three types of igloo, all of different sizes and all used for different purposes. The smallest of all igloos was constructed as a temporary shelter. Hunters while out on the land or sea ice camped in one of these igloos for one or two nights. Next in size was the semi-permanent, intermediate sized family dwelling. This usually was a single room dwelling that housed one or two families. Often there were several of these in a small area, which formed a kind of village. The largest of the igloos was a temporary building constructed for special occasions. This was constructed either by enlarging a smaller igloo or building from scratch. These could have up to five rooms and housed up to 20 people. A large igloo may have been constructed from several smaller igloos attached by their tunnels giving a common access to the outside. These were used to hold community feasts and traditional dances.
Topic ______________ Main idea __________________

Task 3: Read paragraph E) . What is the topic?. What is the main idea? Discuss in groups.
E) Stratford-upon-Avon, an historic medieval market town, is about 80 miles north-west of London. Thousands of tourists come to Stratford every year because it is the birthplace of William Shakespeare, the most famous playwright in the world. Visitors can see the house where Shakespeare was born, the cottage where his wife lived, and other buildings connected with his life. Tourists, however, can do more than sightseeing in Stratford. The town has three theatres and there is no better way to complete a visit to Shakespeare’s birthplace than by seeing one of his plays.
Topic ______________ Main idea __________________

Task 4: Read paragraph F) . What is the topic?. What is the main idea? Discuss in groups.
F) The city of Liverpool, about 200 miles north of London, was once one of the richest and most famous cities in the world. It was the starting point of the ‘triangular trade’ and through this trade became a great port. In the ‘triangular trade’, textiles and hardware were shipped from Britain to West Africa, where they were exchanged for slaves. The slaves were taken to America and the Caribbean and exchanged for rum, sugar and cotton. These goods were brought back to England and exchanged for more textiles and hardware. This evil trade, based as it was on slavery, made Liverpool merchants very, very wealthy.
Topic ______________ Main idea __________________

Task 5: Read paragraph G) . What is the topic?. What is the main idea? Discuss in groups.
G) Hundreds of people who visit Loch Ness in Scotland say they have seen Nessie and many photographs have been taken that claim to show the monster. The question everyone asks is, “What is Nessie?” The answer is nobody knows. Over the years, however, many explanations have been suggested. Some people think Nessie might be a dinosaur that somehow survived when all the other dinosaurs died. Some people think it could be an animal or a fish. Some people think it may simply be the sunlight playing on the water and fooling people’s eyes. The most popular idea is that Nessie might be a plesiosaur. A plesiosaur is a kind of dinosaur that lived in the sea and in deep rivers millions of years ago. There is only one problem with this idea; plesiosaurs became extinct about 65 million years ago. Other people say that Nessie could be a a very large sturgeon, a big fish that can sometimes grow to four or five metres in length. The problem with this theory is that no-one has ever caught a sturgeon, even a small one, in Loch Ness.
Topic ______________ Main idea __________________

Task 6: Read paragraph H) . What is the topic?. What is the main idea? Discuss in groups.
H) European and North American folklore is full of tales of evil and dangerous wolves. Everyone knows the story of little Red Riding Hood, whose grandmother was eaten by a wolf, and the tale of the three little pigs pursued by a ravenous wolf into their houses of straw, sticks and brick is another nursery favorite. The English language is also full of expressions underlining this negative image. An outcast from society is called a ‘lone wolf’; a trickster or hidden threat is a ‘wolf in sheep’s clothing’; when we are really hungry we ‘wolf down our food’. Most horrific of all are the stories of the werewolf: the human who turns into a wolf-like monster when the moon is full. Perhaps there is something buried deep in our collective memories from ancient times when early humans were hunters and the wolf was one of our rivals for food. Whatever the reason, the wolf is a creature with a less than desirable image.
Topic ______________ Main idea __________________

Task 7: Read paragraph I) . What is the topic?. What is the main idea? Discuss in groups.
I) The Roadrunner, created in 1948, is one of the most famous Warner Brothers cartoons. In this cartoon, a hungry coyote chases a bird called the roadrunner that can run incredibly fast. In order to catch the roadrunner, the coyote often uses a variety of complex machines such as rocket packs and jet-powered roller skates that he buys from a mail-order company called the ACME Corporation. Although the name of the company suggests otherwise, the products the coyote buys always fail, and usually in an unexpected or spectacular way. As a result of these failures, the coyote is either blown to pieces, burnt to a cinder or thrown to the bottom of the Grand Canyon. The roadrunner is never caught. The creators of the Roadrunner probably chose the name ACME for the irony it brings to the coyote’s never-ending string of failures to catch the roadrunner.

This is the end of the core reading skills section of this course. Now we are going to practice what you have learned.
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