Expository Essays: Cause and Effect
An expository essay is an essay in which the writer shares information with the reader. The writer supports the main points with factual information. The writer’s personal experience or point of view is not usually included in an expository essay, except perhaps as a hook to get the reader interested in the essay.
Different Types of Expository Essays
There are several types of expository essays, including cause and effect, compare and contrast, classification, and problem and solution. Sometimes, the writer of an expository essay will use more than one pattern of organization in the essay, such as cause and effect and compare and contrast. The choice of organizational pattern depends on the writer’s topic and audience.
Expository Essay: Cause and Effect
A cause and effect essay is a type of expository essay that explains the causes or reasons for an event or natural phenomenon. Writers must be careful to write only facts and make sure that there is a clear relationship between causes and effects or reasons and results. If the relationships between events or phenomena are not absolutely certain, it is important to use appropriate hedging language.
Ways of Expressing Cause and Effect
There are many ways of expressing cause and effect relationships. Some state the cause and effect relationship directly. For example, the words because and so clearly mark the cause and effect in a sentence. Other ways of expressing cause and effect are less direct, and the cause and effect relationship is merely implied, rather than stated directly. For example, the time word when is sometimes used to suggest that one thing leads to another. Writers might use less direct ways of expressing cause and effect if the facts suggest, but do not prove, a clear cause and effect relationship.
Basic Structure of an Expository Essay
Because the purpose of an expository essay is to share information, it is important that the writer’s main points are easy to understand and that the supporting details are well-researched, relevant, and clearly explained.
- A clear thesis statement that states the central idea of the essay
- A topic sentence for each body paragraph
- Development of each topic with relevant factual support
- Clear transitions from one body paragraph to the next
- Restatement of central idea
- A satisfactory ending
Showing Cause and Effect
Some statements of cause and effect are very clear: one thing happens because of another thing. Other statements are less direct, and the cause and effect is implied. For example, when is often used to imply that one action leads to another action.
There are several ways to express cause and effect.
1. Verb phrases – many different verbs can suggest that one thing caused another:
That is why college students play such an influential role in the success or failure of low-budget films.
2. Infinitives of purpose – by using an infinitive, you can show why something happens or what the purpose of an action is:
Other ants follow the trail to find the food.
3. Coordinating conjunctions – the coordinating conjunctions are: and, but, for, nor, or, so, yet. These join two parts of a sentence (=independent clauses), and are useful for showing why something happens, why someone does something, and for comparing one action with another. The coordinating conjunctions for and so are used to express cause and effect relationship:
He needed an inexpensive way to promote the film, so he went on the Internet and visited science fiction chat rooms.
4. Subordinating conjunctions – subordinating conjunctions join a subordinate (= dependent) clause to an independent clause. They can show why something happens. Common subordinating conjunctions are: because, after, though, unless, when, while:
And because the pheromones don’t wear off for several hours, male moths have enough time to find the females and breed.
5. Prepositional phrases – phrases that begin with a preposition can also give the reasons why something happens, either directly or indirectly:
Pheromones are chemicals that animals, including insects, produce for a variety of reasons.
6. Other expressions – expressions such as that is why, the more … the more are ways of directly showing a cause and effect relationship:
The more serious the threat, the more alarm pheromones the ant produces.
Simple present – the simple present tense is used for a general statement of fact. When the cause and effect relationship is one that involves a scientific fact or phenomenon, use the simple present tense.
Simple past – when the cause and effect relationship is one that involves the causes or reasons for a past event, use the past tense.
Reference to Authority
The following pattern is often used when referring to authority:
|[authority] +||[verb] +||[noun clause stating fact]|
|Studies||show||that flowers use pheromones to attract bees.|
Model Text 1: Cause and Effect (Science)
The Language of Insects
Pheromones are chemicals that animals, including insects, produce for many reasons. Plants also produce pheromones. . A For many creatures, life would not be possible without pheromones.
2 Body Paragraphs
B Moths are one insect that could not survive without pheromones. C Moths have poor eyesight, and most species cannot use sound to communicate. Instead, they communicate through pheromones. Female moths, for example, release pheromones from their legs and wings. A male moth can identify female moth pheromones from as many as five miles away. And because the pheromones don’t wear off for several hours, male moths have enough time to find the females and breed.
B Ants have different pheromones for different purposes. C Like moths, ants use pheromones to find each other. They also use pheromones to find food. When an ant finds food, it takes a piece and returns to the nest. Along the way, it releases a trail of pheromones. Other ants follow the trail to find the food. If something blocks the trail, the ants look for a new way to reach the food. When they find the shortest way, they produce a new trail of pheromones. D In this way, pheromones help ants adapt to changes in their environment.
B When an ant is hurt or threatened, it produces an “alarm” pheromone. C Other ants identify the alarm pheromone and immediately come to help. The more serious the threat, the more alarm pheromones the ant produces. In this way, ants can quickly organize to fight insects hundreds of times their size.
B Some species of ants use “trick” pheromones to make trouble and confuse their enemies. C Fire ants, for example, produce pheromones near the nests of other ants. Those ants become confused and begin to fight each other instead of attacking the fire ants.
B Other insects use trick pheromones to imitate another species. In some cases, this protects them from becoming another insect’s meal. C An interesting example is the European blue butterfly. When the butterfly is a caterpillar, it releases a pheromone that is very similar to that of one species of ant. When the ants find a blue butterfly caterpillar in the forest, they think that it is one of their young. They then carry it back to their nest. There, instead of becoming a meal, the caterpillar is fed and protected for ten months. The ants do not suspect that anything is wrong, even when the caterpillar starts to eat their young! The caterpillar finally leaves the nest when it is about to turn into a butterfly.
B Yet another insect uses trick pheromones to attract its next meal. C The bolas spider, a species common in South America and Africa, releases a pheromone similar to that produced by a female moth. The spider then waits for a male moth to arrive. Instead of finding a female, the unsuspecting moth becomes a tasty meal for the spider.
B Because of examples like these, . But pheromones are important not only to insects. They are important to plants and other animals as well. D Their importance in the natural world is undeniable. C . E If that turns out to be true, it might be more accurate to talk about “Love at first smell” than “Love at first sight!”
Model Text 2: Cause and Effect (Social Studies)
The 1999 horror movie The Blair Witch Project surprised audiences. It told a story about three students lost in a forest. At the time, no one had ever seen anything like it. The film also surprised movie companies. C The expenses barely reached $22,000, but the income from ticket and DVD sales was (and continues to be) enormous. The Blair Witch Project is an example of a sleeper. A Sleepers are films that are made for very little money, but are enormously successful. Although it might seem that the makers of The Blair Witch Project just got lucky, there are actually some very specific reasons that certain movies become sleeper hits.
2 Body Paragraphs
B . College students are important for two reasons. First, they do not pay much attention to media reviews of movies. Instead, they listen to their friends’ opinions. And because of social networking sites such as Facebook, the average college student today has hundreds of “friends.” And those friends have hundreds of friends, and so on. That is why college students play such an influential role in the success or failure of low-budget films. C An example is the 1997 comedy Austin Powers. Austin Powers was a low-budget film. At first, ticket sales were low, and it made very little money. But after it came out on video, it became enormously popular on college campuses. In the end, Austin Powers made more money from video and DVD sales than it did in theaters.
B Another secret to sleepers is creative marketing. This also involves the Internet. Internet marketing is cheap, and it can reach a specific audience. C When director David Twohy filmed the science fiction movie Pitch Black in the late 1990s, for example, he needed an inexpensive way to promote the film, so he went on the Internet and visited science fiction chat rooms. He had conversations with people about his movie. Slowly, science fiction fans became interested in the film. “In the end, Internet buzz helped make it a success,” .
B College students and Internet marketing were both important to the success of The Blair Witch Project. C The filmmakers designed a Web page for the movie. It said that The Blair Witch Project was a true story (it wasn’t). It also said the three students in the film had disappeared (they hadn’t). Soon, college students were talking about whether the movie was real or not. Many of them wanted to see for themselves. For the film’s release, theaters were completely sold out. Today, many film studios follow The Blair Witch Project model when promoting their films.
B Of course, to make money, sleepers also need to be good films. The makers of The Blair Witch Project never saw themselves as marketing experts. Similarly, the makers of Austin Powers set out to make a funny movie. D And, as millions who have seen the films would agree, they succeeded.