Tier 3: Content Words
My favorite source on vocabulary knowledge: K through HS is the Text Project. There is an extensive list of resources on this site. Here are some that address Tier 3: Content Words for younger children.
Science (on the playground)
New words in science lessons and texts usually represent unknown concepts (e.g., photosynthesis, erosion). This is different than the new vocabulary in narratives that typically pertain to known concepts (e.g., new words such as raucous and boisterous instead of the familiar noisy). In this presentation, Elfrieda H. Hiebert [presenter] will discuss the need to make science vocabulary education a priority in grades one through four. If the concepts are not taught in grades one through four, later when the students are in the middle grades they will be faced with an inordinate number of challenging words, representing complex and unknown concepts