Veritasium
Season 2 Episode 3 - Cathode Rays Lead to Thomson's Model of the Atom
In the mid 1800's scientists successfully passed an electric current through a vacuum in a glass tube. They saw a glow from the tube that seemed to emanate from the negatively charged plate called the cathode. Since scientists didn't know what the glow was they called it a cathode ray. There was debate over whether the cathode ray was a wave phenomenon like light or a stream of negatively charged particles. JJ Thomson effectively resolved the debate in 1897 by performing a clever experiment that determined the charge to mass ratio of the particles making up the cathode ray. He also showed that this same particle was in all different cathode materials so it must be a constituent common to all atoms. This changed our understanding of the atom from the previous billiard ball model to Thomson's plum pudding model of the atom.
Episodes in Season 2
Atomic Theory
2 min
Thomson's Plum Pudding Model of the Atom
2 min
Cathode Rays Lead to Thomson's Model of the Atom
3 min
Scientific Notation - Explained!
5 min
I'm Atoms (Scientific Cover of Jason Mraz's I'm Yours)
3 min
Scientific Notation - Example
1 min
The Difference Between Mass and Weight
3 min
Egg Experiment to Demonstrate Inertia
1 min
Gravity (Scientific Version of John Mayer's Gravity)
4 min
How Far Away is the Moon? (The Scale of the Universe)
2 min
What is a Force?
3 min
What Forces Are Acting On You?
2 min
Why Does the Moon Orbit Earth?
1 min
What Is Gravity?
2 min
Best Film on Newton's Third Law. Ever.
4 min
Calculating Gravitational Attraction
3 min
Which Hits The Ground First?
3 min
Misconceptions About Falling Objects
3 min
Is There Gravity In Space?
2 min
Three Incorrect Laws of Motion
2 min
Experiments A Cappella
1 min
Khan Academy and the Effectiveness of Science Videos
8 min
What Are Atoms and Isotopes?
3 min
Supercooled Water - Explained!
3 min
How Damaging is Radiation?
4 min
