Discoveries of Electrons and Cathode Ray Tubes
1. Discoveries of Electrons
The discovery of electrons marked a significant milestone in our understanding of matter. Here are
some key points:
- In the late 19th century, J.J. Thomson conducted experiments with cathode ray tubes, leading to the
identification of electrons. He observed a beam of particles traveling from the cathode (negative
electrode) to the anode (positive electrode).
- Thomson discovered that these particles were negatively charged and had a much smaller mass than
atoms. He named them "electrons" and proposed the "plum pudding" model of the atom, suggesting
that electrons were embedded in a positively charged sphere.
- Other scientists, such as Robert Millikan, furthered the study of electrons and conducted experiments
to measure their charge and mass accurately. Millikan's oil drop experiment in 1909 allowed for the
precise determination of the charge of an electron.
- The discovery of electrons revolutionized our understanding of matter and led to the development of
atomic physics and quantum mechanics. It also played a crucial role in the advancement of electronics
and technology.
2. Cathode Ray Tube (CRT)
A cathode ray tube is a device closely associated with the discovery of electrons. Here's what you need
to know:
- A cathode ray tube is a sealed glass tube with electrodes at each end, known as the cathode
(negative electrode) and the anode (positive electrode). It contains a vacuum or low-pressure gas
environment.
- When a high voltage is applied across the electrodes, a stream of particles known as cathode rays is
generated. These rays were later identified as a beam of electrons.
- Cathode ray tubes were first developed in the late 19th century and played a vital role in studying the
properties of electrons. They were instrumental in the discovery and understanding of electrons by
scientists like J.J. Thomson.
3. Properties of Cathode Ray Tubes and Electrons
- Cathode ray tubes can produce a focused beam of electrons that can be deflected by electric or
magnetic fields.
- Electrons have a negative charge, with a magnitude of approximately 1.6 x 10^-19 coulombs.
- The mass of an electron is approximately 9.11 x 10^-31 kilograms, about 1/1836th the mass of a
proton.
- Electrons exhibit wave-particle duality, meaning they can behave like particles or waves depending
on the experimental setup.
- Electrons can be accelerated and decelerated by electric fields, and they can also exhibit magnetic
properties.
4. Creator of the Cathode Ray Tube
The cathode ray tube was developed by a number of scientists, but one notable figure is the German
physicist Karl Ferdinand Braun. Braun's work on cathode ray tubes earned him the Nobel Prize in Physics
in 1909.
5. Discovery of Electrons
Electrons were discovered by J.J. Thomson in 1897 during his experiments with cathode ray tubes.
6. Charge, Mass, and Other Properties of Electrons
- The charge of an electron is approximately -1.6 x 10^-19 coulombs.
- The mass of an electron is about 9.11 x 10^-31 kilograms.
- Electrons have a negative charge, allowing them to be attracted to positively charged particles.
- Electrons exhibit both particle-like and wave-like behavior, as described by quantum mechanics.
- They play a crucial role in chemical reactions, electricity, and the behavior of atoms.
CHEMISTRY ASSIGNMENT
Discoveries of Electron and
Cathode Ray Tube (CRT).
Name: Nathan Sirak
Class: 11C
Submitted To: Mr.
Submission Date: Sep 25/2023