Finding the Main Idea of an Informational Text Using Key Details

Otis and Pearl are on a trip to an old castle! All around the castle are informational plaques and Otis and Pearl want to find the main idea of these to show they understand them! Let's join Otis and Pearl and learn all about finding the main idea of an informational text using key details. The main idea is what the text is mostly about, or the key point that the author is trying to make. Key details, or supporting details, are phrases or sentences that support the main idea of the text. Now we have looked at what a main idea and key details are, let's learn how to find the main idea! Here is a passage from a plaque that Otis and Pearl came across in the castle under a knight. 'Knights were around in the Middle Ages, and usually came from high standings to fight for kings. Their armor could weigh up to fifty-five pounds, which they wore all day in battle. On top of this, swords could also weigh up to ten pounds, especially two-handed versions. Alongside the heavy armor, and wielding swords, they would also carry shields in battle, which could weigh up to eight pounds. Imagine wearing and carrying that weight all day!' A graphic organizer like this can help us in finding the main idea. Finding at least three supporting details can help us find the main idea. Looking at the text, you may notice it spoke repeatedly about the weight of items knights wore or used, so this is a good clue that these are our supporting details. For example, the text says 'their armor could weigh up to fifty-five pounds, which they wore all day in battle'. We can add this as a supporting detail. In the text, we also see 'swords could also weigh up to ten pounds'. This is our second supporting detail. Going back to the text, we see, 'they would also carry shields in battle, which could weigh up to eight pounds'. This is our final supporting detail! Now, ask yourself: 'what is the main idea?' Since the text specifically focused on how heavy the gear of a knight was, we can say the main idea is 'knights wore lots of heavy equipment'. It looks like Otis and Pearl have found another plaque about the moat! The text on this plaque reads, 'moats were created to surround a castle, which was extremely useful when defending against attackers. Moats were deep, making it hard for attackers to get across to the castle. If attackers tried to swim through a moat, they would be vulnerable to castle guards. Castles with moats were usually safer from attacks than castles with no moats!' Find the main idea on your own this time, locating three supporting details to help you! Pause the video, and press play when you are ready to continue. The supporting details are 'moats were created to surround a castle', 'moats were deep, making it hard for attackers to get across', and 'if attackers tried to swim through a moat, they would be vulnerable to castle guards'. What is the main idea of this text? The supporting details talk about protection for the castle, so the main idea is 'moats offered protection against attackers'. While Otis and Pearl continue their castle tour, let's review. Remember, to find the main idea of the text, use a graphic organizer like this. Find three supporting details and think, 'what is the supporting details in the text trying to tell me?' Then, write the main idea! "Pearl! Where are you?" "Here, I'm here in the water!" "That was not re-moat-ly funny, Pearl."