Topic Sentences

Look at the two following 'paragraphs'. One is a real paragraph and one is not. Which is which and why?

A) Asteroids, also called minor planets or planetoids, are a class of astronomical objects. The term asteroid is generally used to indicate a diverse group of small celestial bodies that drift in the solar system in orbit around the Sun. Asteroid (Greek for "star-like") is the word used most in the English literature for minor planets, which has been the term preferred by the International Astronomical Union; some other languages prefer planetoid (Greek: "planet-like"), because it more accurately describes what they are.

B) A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail — both primarily from the effects of solar radiation upon the comet's nucleus, which itself is a minor body composed of rock, dust, and ice. The Comet was the first jet passenger aircraft which entered service with British Overseas Airways Corporation in the 1950's. Comets' orbits are constantly changing: their origins are in the outer solar system, and they have a propensity to be highly affected (or perturbed) by relatively close approaches to the major planets. The Houston comets are a women's basketball team playing in the WNBA.

	Paragraph?	Why or why not?
A)	Yes or No
B)	Yes or No

Task 1: With a partner come up with a definition of a paragraph.

Tip 1 If we ask ourselves the questions What is this about? What is the general idea? What is the topic? What is the subject?, we can usually find the topic of a paragraph and this makes it easier for us to understand it. One quick way to do this is to find the topic sentence of the paragraph. Very often this is the first sentence in the paragraph. Be careful!!! It is often the first sentence but not always. Sometimes it's the second or third sentence and sometimes there is no topic sentence at all. If there is no topic sentence the paragraph as a whole will give us the topic.

Task 2: Read the passage and decide what the topic sentence is (if it has one).
Most of the bridges in the world can be classified into four types: beam, arch, cantilever and suspension. Beam bridges, the simplest form, have rigid beams that are supported at each end of the bridge’s span. Arch bridges, however, use the shape of the arch to ingeniously make the weight of the bridge push into the ground at either end of the span. Cantilever bridges, like beam bridges, have long rigid sections but in a cantilever bridge they are supported in the middle rather than at each end. Suspension bridges have tall towers from which wires are strung and the bridge is suspended from them.
What is the topic sentence? ______________
What is the topic? ________________
Task 3: Read the passage and decide what the topic sentence is (if it has one).
The most essential factor in producing an accurate weather forecast is gaining a supply of precise information on weather conditions all across the globe. Because the weather in Europe today could affect the weather in Africa or America a few days or weeks later, meteorologists have to know what kind of weather is occurring in all areas of the planet. From a vast network of ships, airplanes, balloons and land-based weather stations, data is collected many times a day and fed into the Global Telecommunications System. The information is then distributed by cable, radio and satellite links to all corners of the earth. Local weather forecasters can then take what data they need to come up with an accurate forecast for their area.
What is the topic sentence? ______________
What is the topic? ________________
Task 4: Read the passage and decide what the topic sentence is (if it has one).
Over the centuries, in various parts of the world, many different things have been used as money. Cows, sheep, cocoa beans, seashells and even sharks’ teeth have fulfilled this function at one time or another. However, as people’s appreciation of the value of money became more sophisticated, it was realized that gold and silver were particularly suited to being used as money. Both were scarce metals and therefore able to keep their value. Both of them are portable. Both can be easily fashioned into coins and can be polished to give them an attractive appearance. Equally important, neither of them was prone to rusting away. Large numbers of coins, however, are quite heavy and in the 18th century people began to deposit their gold in banks and in return received a note from the bank promising to pay the amount deposit. These ‘bank notes’ eventually developed into the paper money that we still use today.
What is the topic sentence? ______________
What is the topic? ________________
Task 5: Read the passage and decide what the topic sentence is (if it has one).
The electricity that is generated from exploiting the downward flow of water is called hydroelectricity. The centerpiece of the system is a machine called a turbine. The turbine is little more than a high tech version of the ancient waterwheel. As the water flows through the turbine it turns a series of blades or wheels which are connected to a dynamo. The turning wheels provide the energy which the dynamo converts to electricity. The best areas for locating hydroelectric plants are hilly or mountainous regions with a high rainfall. Usually a natural lake or a man-made reservoir provides a giant store of water that can be tapped at will. Dams are often built to increase the size of natural lakes and more efficiently control the water flow. The turbines are housed in a generating station built below the water source and the force of gravity is all that is needed to propel the water through the turbines.
What is the topic sentence? ______________
What is the topic? ________________

Task 6: Read the passage and decide what the topic sentences of the three paragraphs are (if they have one).
1) Earthquakes are one of the most destructive forces in nature. They can cause damage directly by the shaking of the earth which destroys buildings and other structures in the immediate vicinity of the earthquake and indirectly by causing tsunamis, or giant waves, which can strike coastal areas thousands of miles away. In attempting to rate earthquakes and decide which was the greatest ever, we can use two different approaches. First we can use seismological data based on the Richter scale to give us an idea of the energy released by an earthquake. Second we can measure the destructiveness of an earthquake by the amount of damage it causes, especially loss of human life.
What is the topic sentence? ______________
What is the topic? ________________
2) In the case of the former, the greatest ever recorded earthquake occurred in Chile on May 22, 1960. The epicenter of the Great Chilean Earthquake was 100 miles off the coast of southern Chile and the magnitude measured 9.5. Nearby coastal towns were heavily damaged although, fortunately, a series of smaller earthquakes, called foreshocks, preceded the main earthquake and as a result most people had run out of their houses and into the streets before the big quake struck. The earthquake caused a giant tsunami which raced across the Pacific and struck the Hawaiian town of Hilo causing great destruction. A total of around 3,000 people lost their lives to this combination of earthquake and tsunami.
What is the topic sentence? ______________
What is the topic? ________________
3) In terms of human life lost, the Andaman-Sumatran Earthquake, as scientists call it, was one of the greatest earthquakes ever. It occurred on December 26, 2004, with an epicenter under the sea just off the north coast of the Indonesian island of Sumatra. This earthquake also created a giant tsunami which caused serious damage in many areas bordering the Indian Ocean. Sri Lanka, the Andaman Islands, the south-east coast of India, northern Sumatra and the Thai island of Phuket were all seriously affected: there was even someone killed in Port Elizabeth, South Africa, more than 5,000 miles from the epicenter of the earthquake. An exact total of the deaths caused by this tsunami is impossible to calculate as many bodies were swept out to sea, but it is likely that at least 275,000 people lost their lives in what became known as the Indian Ocean Tsunami disaster.
What is the topic sentence? ______________
What is the topic? ________________

Task 7: Read the passage and decide what the topic sentences of the four paragraphs are (if they have one).
1) Smallpox, also known by its Latin name variola, is a serious, contagious disease. It is often fatal. There is no specific treatment for smallpox, and the only prevention is vaccination. The name smallpox comes from the Latin word for “spotted” and refers to the raised bumps that appear on the face and body of an infected person.
What is the topic sentence? ______________
What is the topic? ________________
2) There are two main types of smallpox. Variola major is the more severe and more common form of smallpox. Historically, variola major has an overall fatality rate of about 30%.. Variola minor is the less common form of smallpox, and is a much less severe disease, with death rates historically of 1% or less.
What is the topic sentence? ______________
What is the topic? ________________
3) Generally, direct and fairly prolonged face-to-face contact is required to spread smallpox from one person to another. Smallpox also can be spread through direct contact with infected bodily fluids or contaminated objects such as bedding or clothing. It is even possible, but rare, for smallpox to be spread by a virus carried in the air in enclosed settings such as buildings, buses, and trains. Humans are the only natural hosts of variola. Smallpox is not known to be transmitted by insects or animals.
What is the topic sentence? ______________
What is the topic? ________________
4) Smallpox is caused by the variola virus that emerged in human populations thousands of years ago and there have been periodic outbreaks of the disease throughout that time. However, a highly successful long-term program of vaccination has succeeded in eradicating the disease. In other words smallpox has been completely eliminated and now only exists in research laboratories. The last known case of smallpox occurred in 1977 in Somalia.
What is the topic sentence? ______________
What is the topic? ________________

Go on to Main Ideas