A couple of nice activities using Oreo cookies (or in my case, cheaper alternatives).
Explain that the upper cookie is the lithosphere, the creamy filling is the asthenosphere, and the lower cookie is the lower mantle. Begin by simulating the motion of the rigid lithosphere plate over the softer asthenosphere by sliding the upper cookie over the cream. Then break the top cookie in half and simulate a divergent plate boundary by sliding the two cookie halves apart.
Push one cookie half under the other to make a convergent plate boundary.
Finally, simulate a transform plate boundary by sliding the two cookie halves past one another. Students should feel and hear that the two ‘plates’ do not glide smoothly past one another (thus modelling the earthquakes that occur at transform fault lines such as San Andreas).
Simply remove the top cookie to reveal the creamy filling beneath. Scrape away and shape the cream to show the phases of the moon. Students should draw the relative location of the Earth and label the phases. Great as a revision tool or plenary.