Begin by showing students how the organization of informational texts can help determine the meaning of words. This includes the use of titles, subtitles, headings, bold or italicized text, and sections. Then share the strategies they can use when they encounter an unknown technical word: Re-read the text and read ahead, identify context clues, decide on a meaning, and plug the meaning into the text to see if it makes sense.
Read the passage about sharks and guide students through these steps to determine the meaning of the words "otoliths" and "radiocarbon." Do this again with another scientific text and determine the meaning of the words "ptyalin" and "mastication."