The topic sentence is the main idea, and often the first sentence, of a paragraph. Second-graders can learn the importance of a topic sentence and sticking to one idea for a paragraph, as well as how to organize a paragraph. After learning how to identify topic sentences, students can create their own.

Identifying the Topic Sentence

Before teaching second-graders how to write a topic sentence, help students learn how to identify the main idea. The topic should be general enough to umbrella all the details in the paragraph, but also specific enough that it gets a point across. For example, “Everyone has families” is a broad statement to begin a paragraph about a student’s family, but “My parents, sister and dog are my family” is more specific, yet general enough to include details about that student’s family. Read paragraphs with your second-graders and underline the topic sentence in each one. Discuss why these sentences outline the main idea of the paragraph. You can also give students a few lists of details and topic sentences, and ask students to match the topic sentence to the correct list of details.

Learning How to Organize Ideas

Read paragraphs as a group and identify both the topic sentence and the supporting details. All statements in the paragraph should refer back to the main idea. When looking at paragraphs together, underline topic sentences in one color and the supporting details in another color. Next, give students a topic idea and ask them to brainstorm details; make an outline for the paragraph. If the paragraph is about the Fourth of July, the paragraph can discuss fireworks, parades and eating red, white and blue food. Write these details in separate sentences, followed by writing a topic sentence about the whole paragraph, such as “My family and I enjoyed the Fourth of July holiday.”

Using Analogies

Tell students that many paragraphs follow the same structure. Reading Rockets compares paragraphs to a hamburger: Paragraphs have a topic sentence, or the top bun; the details, or the hamburger patty; and a concluding statement that restates the topic, or the bottom bun. This analogy gives students a visual representation of the components of a paragraph, and it helps them structure the paragraph. Read some paragraphs with students and underline the top and bottom bun sentences. You can also provide students with the hamburger patty sentences, and ask them to create a topic sentence and concluding sentence.

Improving Sentences

Give students tips for writing good topic sentences. For example, topic statements can begin with the subject of the paragraph. If the topic is “my pet,” the topic sentence could be, “My pet is a very playful puppy.” Another type of sentence has a comma, and what comes after the comma tells the reader what the paragraph will be about. These sentences begin with statements such as “Although there are many things I love,” and could end with topic statements like, “I love soccer the most." Practice writing these kinds of topic sentences with your second-graders, and then ask them to write their own paragraphs and underline the topic sentences. Read the paragraphs aloud and ask if they stayed on topic. If the topic sentence is about a student's own pet, point out if your student writes a sentence about a friend's dog or animals at the zoo, which might stray too far from the main idea. If students have difficulty staying on topic, use a graphic organizer that helps students visualize what happens first, next, then and last; they can keep this same order in their paragraphs.