1. Energy-Mass Equivalence
Niels Bohr
Max Planck
Albert Einstein
Modern Physics
20th & 21st century
Louis de Broglie
Werner Heisenberg
Relativity
Energy-Mass Equivalence
Uncertainty
Quantum Mechanics

2. E=mc2
In nuclear reactions, energy can be converted into mass and mass into energy.
Fission: splitting an atom (WWII Bomb)
Fusion: joining atoms (how the sun makes energy)

4. The Lorentz Factor
Distances (space) contracts by this factor as you approach the speed of light.

5. Graphing shows that γ doesn’t grow much beyond 1 until you reach about ___% of the speed of light

6. Einstein applied the Lorentz factor to time
Einstein applied the Lorentz factor to time. Thus, time _______s at high speed

7. …and mass……
So if you try to get something up to light speed, it just keeps getting heavier and harder to move.
……increases

8. Length Contraction – Equation
Length contraction takes place only along the direction of motion.
Section 26.4

9. Another Verification of General Relativity
General Relativity predicts that a light ray passing near the Sun should be deflected by the curved spacetime created by the Sun’s mass.
The prediction was confirmed by astronomers during a total solar eclipse.
Section 26.8

10. Black Holes * were theorized from Einstein's theory of gravitation.
* General relativity says gravity bends light and warps space and time.
* Black holes are old, very dense, dead stars that attract like so strongly that nothing can escape their pull, not even light.
* We think black holes may be at the center of many spinning galaxies, sucking stars in.
* Time itself is radically altered near and in black holes.

11. Thought Experiment – Werner Heisenberg’s Uncertainty Principle
A thought experiment for viewing an electron with a powerful microscope
In order to see the electron, at least one photon must bounce off it.
During this interaction, momentum is transferred from the photon to the electron.
Therefore, the light that allows you to accurately locate the electron changes the momentum of the electron.
Section 27.8

12. The Uncertainty Principle
Mathematically,
It is physically impossible to measure simultaneously the exact position and the exact linear momentum of a particle.
Physics admits there are some things we simply cannot ever know, no matter what!
Section 27.8

13. The Compton Effect
Compton saw that X-ray photons collided with team particles in a cloud chamber, knocked electrons off the water molecules. Photons acted like particles in collisions.
Energy and momentum were conserved.
Section 27.5

14. Louis de Broglie – 1987
Found a way to describe electrons as waves in 1924.
postulated that because photons also have wave and particle characteristics, perhaps all forms of matter have both properties.
Section 27.6

15. de Broglie Wavelength and Frequency
The de Broglie wavelength of a particle is
The frequency of matter waves is
Section 27.6

16. Electron’s Orbit
The circumference of the electron’s orbit must contain an integral number of de Broglie wavelengths.
2 π r = n λ
N = 1, 2, 3, …
Section 28.3

17. Particle accelerators have revealed that there are a LOT more particles inside the atom than protons, neutrons and electrons

18. The Standard Model of Matter
Particle accelerators have revealed that there are a LOT more particles inside the atom than protons, neutrons and electrons
The Large Hadron Collider (LHC) in Switzerland is the most powerful accelerator in the world. It went online in Smashing particles together forces ousub-atomic particles we have never seen before.

19. The Standard Model of Matter