1. Module 7

1.8. Lesson 2

Lesson 2

Module 7—Investigating the Nature of the Atom

 

Lesson 2—The Millikan Experiment

 

Get Focused

 

A photo of Millikan’s original lab bench shows the parallel plate chamber he used to determine the elementary charge.

This photo, dating back approximately 100 years, shows the lab bench and equipment of physicist Robert Andrews Millikan. Together with his graduate student, Harvey Fletcher, Millikan used the large, black vessel visible on the table to measure a fundamental quantity, one that is related to all the matter in the universe—the elementary charge of an electron!

 

Inside that vessel, Millikan determined the elementary charge of an electron and, in conjunction with Thomson’s work, he also determined its mass! How was it possible to measure the charge of an electron using a little bit of oil and two electric plates inside a sealed container?

 

In Lesson 2 you will learn about Millikan’s oil drop experiment and how he determined the elementary charge of an electron.

 

In this lesson you will answer the following essential questions:

  • How were Millikan’s experimental design and apparatus applied to determine the charge of a single electron?

  • How did the new fundamental quantity, the elementary charge, inform models of the atom?

  • Why did Millikan’s use of scientific judgment cause a controversy among other scientists and scholars?
Module 7: Lesson 2 Assignment

 

Your teacher-marked Module 7: Lesson 2 Assignment requires you to submit responses to the following:

  • Lab—LAB 1
  • Assignment—A 1, A 2, A 3, A 4, and A 5
  • Discuss—D 1

The other questions in this lesson are not marked by the teacher; however, you should still answer these questions. The Self-Check and Try This questions are placed in this lesson to help you review important information and build key concepts that may be applied in future lessons.

 

After a discussion with your teacher, you must decide what to do with the questions that are not part of your assignment. For example, you may decide to submit to your teacher the responses to Try This questions that are not marked. You should record the answers to all questions in this lesson and place those answers in your course folder.