Main Idea and Supporting Details

1. Show six cards: "Beavers," "Beavers change the land around them," "Penguins," "Penguin fathers keep the eggs warm," "Deserts," "Desert animals hide from the midday heat."
2. Pairs sort them into two piles. Ask: "What do the cards in this pile have that the others do not?"
3. Fish for: the second pile are sentences — they SAY something. The first pile only names a subject. Write on the board: "Topic = what it is about (a few words). Main idea = what the text says about it (a sentence)."

1. Read the text aloud. Paragraph 1: "A beaver family can turn a stream into a pond. They cut down small trees with their strong front teeth and drag the branches to the water." Paragraph 2: "The beavers pile up branches, mud and stones to build a dam. Water backs up behind the dam, and a new pond slowly forms. Soon ducks, frogs and fish move in." Paragraph 3: "Beavers have flat tails shaped like paddles. In just a few years, a beaver family can change a whole valley."
2. Ask: "What is this text about, in one or two words?" Take "beavers." Write it in the topic box.
3. Ask the real question: "What does the text SAY about beavers?" Take attempts and improve them aloud. "Beavers build dams" is close but leaves out the ponds and the valley. Settle on: "Beavers change the land and water around them by building dams."
4. Find two supporting details and write the "because" line for each: "They pile up branches, mud and stones to build a dam" supports it because the dam is how they change the stream. "A new pond slowly forms" supports it because the pond is the change.
5. Now point at "Beavers have flat tails shaped like paddles." Ask: "Is this about beavers? Yes. Does it show beavers changing the land?" Try to write the because line aloud and let it fail. That detail is on the topic but does not support the main idea.
6. Point out where the main idea really showed itself: the LAST sentence, "a beaver family can change a whole valley," not the first. The first sentence is a hint, not a rule.

“The topic is what the text is about. The main idea is what the text says about it — and it is always a sentence. If you cannot finish "this supports it because…", the detail is on the topic but it is not support.”

1. Give pairs a second text, "How Penguins Keep Eggs Warm": "Emperor penguin fathers do a hard job in winter. Each father holds an egg on his feet under a warm flap of skin. For about two months he does not eat. Penguins are very good swimmers. The fathers huddle together to stay out of the icy wind until the chick hatches."
2. Pairs fill the organizer: topic ("emperor penguin fathers"), main idea as a sentence ("Emperor penguin fathers work hard to keep their eggs warm in winter"), and two details with because lines.
3. Each pair must also find the one detail that is on the topic but does not support it. Expected: "Penguins are very good swimmers."
4. Take feedback. If a pair writes "Penguins" as the main idea, ask: "What does the text say about penguins?" and wait for a sentence.

“Read me your main idea. Does it have a verb? Is it something the text SAYS, or just something it is about?”

1. Students complete the printable practice sheet: a passage, a main-idea line, and detail boxes.
2. Before they start, remind them that the main-idea line must be a full sentence and each detail needs a because line.
3. Circulate and read only the main-idea lines first; a noun phrase there is the quickest error to spot and fix.

1. Ask three students for the main idea of the beaver text in one sentence. Ask the class to show thumbs up only if each answer has a verb and says something about beavers.