Module 8 Lesson 2

Module 8—Mechanical Waves

Lesson 2—Wave Reflection

Get Focused

Two men wearing hard hats are seen working on a oil drilling platform in this photograph.

The oil and gas industry of Alberta supplies a significant amount of energy for world markets. In order to help supply the world demand for energy, new sources of oil and gas need to be found as old sources are consumed. Drilling for oil, as seen in the photo here, is costly and dangerous, so oil companies want to have each drilling operation strike productive petroleum deposits. Geologists are employed to explore the subsurface of the ground in an attempt to predict the presence of valuable oil or gas reserves. One of the tools at their disposal is reflection seismology. In this process, a seismic wave is produced on the surface of Earth by TNT or an air gun explosion. The energy of the explosion (similar to a tiny earthquake) travels outward through the ground as seismic waves. Matter deep beneath the surface reflects some of the wave energy. The reflected waves are recorded by a geophone, a portable sensor that converts seismic waves into an electrical signal.

Using the data from the reflected waves, the geologist estimates the properties of the subsurface. In turn, this helps to reduce needless drilling expenses, dangers, and environmental disturbances by focusing exploration on areas that are likely to contain oil and gas deposits of significant value.

The reflected waves that are recorded in seismic geology contain information about the material, or boundaries, that reflected them. How does this reflection occur, and how is it applied in various situations and circumstances to help us understand the physical makeup of the ground beneath our feet?

As you work through this lesson, keep these questions in mind:

What is the difference between a wave and a ray?
What happens when a wave encounters a boundary?
What is Huygens’ Principle? How can it help to understand wave reflection?

Module 8: Lesson 2 Assignments

Your teacher-marked Module 8: Lesson 2 Assignment requires you to submit a response to the following:

Try This—TR 1, TR 2, and TR 3

You must decide what to do with the questions that are not marked by the teacher.

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.