Chapter 1
The ancient philosophical spark
Chapter 2
Cracking the shell
Chapter 3
Mapping the nucleus
Chapter 4
The quantum cloud
YOUR GOAL
Master of The story of the atom
Ch 2 · Cracking the shell
testerr Cracking the Shell
We cracked the atom’s shell (cracked the shell!) / Found the tiny electron running well (running well!)
testerr Early scientists imagined the atom as a sweet British dessert of positive and negative charges.
testerr J.J. Thomson discovered the first subatomic particle, proving the atom is not indivisible.
BETA
testerr Aim neutrons at the heavy nucleus to discover how splitting an atom releases energy.
Fun Fact
Weighing electrons: An electron is so light that it would take about 29 million trillion trillion of them to weigh a single ounce.
Glossary
electron (noun)
A stable subatomic particle with a charge of negative electricity, found in all atoms. In 1897, J.J. Thomson discovered this particle, proving that the supposedly indivisible atom has an internal structure.
A stable subatomic particle with a charge of negative electricity, found in all atoms. In 1897, J.J. Thomson discovered this particle, proving that the supposedly indivisible atom has an internal structure.
Quiz
Which city did John Dalton live and teach in when he formulated his atomic theory?
Quiz
What subatomic particle did J.J. Thomson discover in 1897 using a cathode ray tube?
Quiz
Which American physicist conducted the famous 1909 oil drop experiment to measure electron charge?
Quiz
In 1803, which English schoolteacher published the first modern scientific atomic theory?