Demonstrating Plate
Boundaries Script
Teacher: Hold your hands out in front of you with the fingertips of each hand pointed in towards each other and touching. Slowly push your fingertips together.
Question: If you continued pushing your fingertips together, what do you think your fingertips might do?
Teacher: Imagine that your hands represent two plates.
Explain to students that now their right hand/”plate” is denser than the left.
The denser right hand/plate represents oceanic crust, while the less dense left hand/plate represents continental crust.
Question: What is oceanic crust? Answer: Oceanic crust is crust that has
oceans located on it.
Question: What is continental crust? Answer: Continental crust is crust that has continents located on it.
Question: If one of your hands/plates is denser than the other, what will happen when you push the two together? Answer: Students should remember that denser materials sink.
Teacher: Remember we have learned that denser materials sink below less dense materials. As a result, the hand/plate that is denser will sink below the hand/plate that is less dense.
Teacher: Now let’s start with the same model we had earlier. Hold your hands out in front of you with your fingertips of each hand pointed in towards each other and touching. Your right hand should now represent the more dense oceanic crust and your left hand the continental crust.
Have students repeat the process of slowly pushing their fingertips together.
Students should show that the right hand goes under the left one as the two
“plates” collide.
Teacher: This type of boundary where two plates push together is a
convergent boundary. When one plate is denser and goes under the other this is called subduction.
Have students write the definitions of convergent boundary (and draw images if desired) and subduction.
Question: What do you think might happen when two plates collide?
Question: On “Map 2”, can you find a plate boundary where two plates collide?
Answer: varying answers. One example is the boundary between the Nazca
Plate and the South American Plate
Question: Are there any volcanoes near that plate boundary? Answer: yes
Teacher: So, one place that volcanoes might occur is where two plates collide.
Volcanoes can form at an oceanic and continental boundary or they can also form at an oceanic-oceanic boundary.
Question: Do volcanoes always form when two plates collide? Can you find an example on the map where plates are colliding, but there are no volcanoes?
Answer: Volcanoes do not always form when plates collide. Where the Eurasion plate collides with the Indo-Australian plate – there are no volcanoes.

Demonstrating Plate
Boundaries Script
Teacher: This is an example of where neither plate went under the other.
Instead the two plates collided and pushed each other up, creating the
Himalayan Mountains.
Teacher: Have students use their hands to model this type of boundary. As their fingertips touch, they should push up, instead of sliding one under the other.
Teacher: Have students hold hands out in front again with the fingertips of each hand pointed in towards each other and touching. Have students slowly pull their hands apart. The students are now modeling a divergent boundary
– a boundary where two plates are pulling apart from one another. As the two plates pull apart at a divergent boundary, pressure is released and this causes magma to rise, and can form volcanoes.
Have students write the definition (and draw images if desired) of divergent
boundary.
Teacher: Have students hold hands out in front again with the fingertips of each hand pointed in towards each other and touching. Have students move hands back and forth against each other. Let student know that this model represents a transform boundary – a boundary where two plates slide past one another.
Have students write the definition (and draw images if desired) of transform
boundary.
Question: What do you think might happen at this type of this boundary?
Answer: Earthquakes
Have students now answer the questions on the “Locations of Volcanoes –
Activity 2” sheet.
Teacher Discussion Points for plate movement:
Question: Plates are sections of what layer of the Earth? Answer: Plates are sections of the lithosphere.
Question: What layer of the Earth is under the lithosphere? Answer: The
asthenosphere is under the lithosphere.
Question: How would you describe the asthenosphere? Answer: The asthenosphere is a part of the upper mantle that is partially molten. It is what the lithosphere rides upon.
Teacher: Because the asthenosphere is partially molten and denser than the lithosphere, the plates move on top of the asthenosphere at the rate of centimeters per year. This theory of movement of the plates over the asthenosphere is called plate tectonics.

Demonstrating Plate
Boundaries Script
Have students write the definition (and draw images if desired) of plate
tectonics.