Supporting Ideas with Facts

When you write to tell people about a topic, you start with one main idea. Then you need facts that back up that idea. Not every true fact belongs in your paragraph. In this lesson, you will learn how to pick the facts and special words that truly support your main idea, and how to spot the ones that do not belong.

A main idea is the one big point you want readers to understand. Every fact you add should help prove or explain that point. Suppose your main idea is: "Honeybees are important pollinators." A fact that supports this idea is: "As a bee collects nectar, pollen sticks to its legs and rubs off on the next flower it visits." This fact explains exactly why bees matter for plants.

A supporting detail does not have to be long. It just has to connect clearly to the main idea. Short, exact facts work better than vague ones.

A relevant fact is one that actually supports your main idea. Before you add a fact to your paragraph, ask yourself: "Does this fact explain, prove, or add detail to my main idea?" If the answer is no, the fact does not belong, even if it is true and interesting.

Look at these two facts about the main idea "Honeybees are important pollinators":

• "A bee visits about fifty to one hundred flowers on a single trip." (This supports the main idea. It shows how much pollinating one bee does.)
• "Bees can see the color yellow very well." (This is true, but it does not explain why bees are important pollinators. It is off-topic here.)

Learning to sort facts this way is a skill you will keep building. Using Evidence and Technical Vocabulary takes this same idea further with more detailed sources.

Subject-specific words, sometimes called domain words, are exact terms that belong to one topic. Using them makes your writing clearer and shows your reader you understand the subject. Instead of writing "bees make stuff for their home," you write "worker bees produce wax to build the honeycomb inside the hive."

Here are some subject-specific words for a paragraph about bees: pollen, nectar, hive, colony, and worker bee. Each word names one exact thing. When you research a new topic, keep a short list of these words so you can use them in your own writing.

Look at the diagram below. The main idea sits in the middle. Two facts connect to it because they support the idea. One fact is crossed out because it does not connect to the main idea, even though it is true.

Now try building your own paragraph. Pick a main idea, list three facts, and check each one with the relevance question. Then add one or two subject-specific words to make your sentences more exact. For more practice sorting strong evidence from weak evidence, see Analyzing Evidence and Technical Language.

Main Idea: The one big point a paragraph is trying to tell the reader.

Supporting Fact: A true detail that explains or proves the main idea.

Relevant: Closely connected to the main idea, so it belongs in the paragraph.

Subject-Specific Word: An exact word that belongs to one topic, like "hive" or "nectar" for bees.

Detail: A small, specific piece of information that adds to a bigger idea.

Related lessons

• Using Facts and Domain Words