(STEM stands for Science, Technology, Engineering and Math. PBL stands for Project Based Learning.)
Eighth grade students recently worked on a geologic time unit and got to explore how scientists have learned how to calculate the age of rocks, what fossils tell us about past life forms, and the vast expanse of time Earth has been around. They learned about fossils, absolute and relative dating, and the four major eras of geologic time.
Students started the unit by creating scale model timelines of the eras of time. If each billion years Earth has been around was represented by a meter, a timeline would have to be 4.6 meters long. Students were shocked as they put this into perspective by creating this model.
Next, the class worked through interactive stations learning about relative dating. One example is students rotated though the Corndog Factory where they had to make a corndog with playdough and popsicle sticks. They then decided which had to be older or created first (the corndog, before the stick could cut through it). This taught them the relative dating principle of intrusions. Intrusions are younger than the rock they intrude upon.