Teacher asks the students to review some facts they already know about deserts. Teacher tells the class that they will be looking at cacti today. She tells them that they will also be learning about a special type of cactus, the saguaro cactus. She gives each group a cactus to examine. Students will write what they observe in their Response Notebooks.
Teacher asks the students what they observed.
Teacher asks the students what the spines might be used for. She then explains that trees with broad leaves, such as those in our region, may lose up to 100 gallons of water a day. She asks students why plants such as these could not survive in the desert. She explains that they will be doing an experiment to show how important the waxy covering is. Teacher shows the groups that they will be given 2 sponges, one covered on all sides but one with Vaseline.