# Experiential Learning Homework

Identify a connection between something in the world that you are trying to explain and a theory that is used to explain that.

In my next teaching practicum, I will be trying to explain how geologists have inferred the structure of the Earth’s interior using the theory that seismic waves will reflect and refract at boundaries between layers of varying composition and density. This is a difficult concept to explain since we cannot see the interior of the Earth so students have to accept this theory as proof that the interior of the Earth is highly differentiated.

How are you helping your students make that connection?

Reflection is a common concept that is generally well understood so the focus in explaining this theory will be on refraction. A common example of refraction is how a pencil “breaks” when it is placed in water because the light is refracting as it travels from air to water. This is a good example to use because students will have likely seen this effect in their daily lives.

This theory will also be explained using P- and S-wave shadow zones. Students will be shown images of where on Earth P- and S-waves would be detected if an earthquake that originates at point X could generate seismic waves that could travel through the entire Earth. The connection here is not as strong because we cannot model that S-waves can’t travel through liquids, which is the evidence used to explain the S-wave shadow zone. If they accept this they can then understand that the outer core must be a liquid to create the size of the observed S-wave shadow zone.

Does your process help your students be able to make connections beyond that particular exercise? How does it do that? and if not, what can you do to help them be able to do that?

I found this question difficult to answer since I’m only giving one lecture in the course and will not be interacting with the students after that, so I think it’s hard to say if they will make connections with this theory after my lecture. I think the use of a real-world example (the pencil in water) is memorable and I hope that students will think of that example when they have to apply refraction in other situations. Also, if students decide to continue studying geology, the concept of a differentiated Earth will be referred to time and time again and they will learn countless more examples that support this theory. Specific to my lecture, I will also be talking about the Earth’s magnetic field, which can only occur because the Earth is differentiated. This is a second example that requires the Earth to be differentiated and will hopefully allow students to make connections between seismic refraction and the Earth’s magnetic field.