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ATOMIC AND NUCLEAR PHYSICS.pdf
- 2. M a x P l a n c k -a German Physicist -made a bold step towards a new understanding of the nature of light
- 3. - tiny particles (not possible to see through the naked eye) -everything that exists on the universe is made up of atoms -it is made up of even smaller particles called "subatomic particles" -consists of a central nucleus (protons and neutrons) Atomic Physics
- 4. -Protons are positively charged and neutrons have no charge (neutral) which makes the nucleus an overall positive charge -if the Sun has planets orbiting it, the nucleus has electrons orbiting it (which are negatively charged) -because nucleus is positively-charged and electrons are negatively charged, they are ATTRACTED TO EACH OTHER Atomic Physics
- 5. Question! What are things smaller than subatomic particles?
- 6. Answer! Quarks. These quarks are the fundamental building blocks of matter; smaller than physicists can measure
- 7. Atomic Spectra When atoms are excited, they emit light of certain wavelengths which correspond to different colors. Each element has a specific pattern like a barcode. The emitted light can be observed as a series of colored lines with dark spaces in between; this series of colored lines is called atomic spectra. If we see a planet passing in front of its star, some of that starlight is absorbed in a very specific pattern called "atomic absorption spectrum."
- 9. 2 Kinds of Atomic Spectra Absorption Spectra - light source is behind a gas and the gas absorbs and scatters certain wavelengths of light leaving dark lines in the spectrum 1.
- 10. 2 Kinds of Atomic Spectra 2. Emission Spectra - same process but seen in a different angle
- 11. Question! In atomic spectra, why do we get these very specific lines?
- 12. Answer! Each type of atom has its own unique pattern of electron orbits. No two sets of orbits are exactly alike.
- 14. Answer! Light is a wave. And also, light is a form of energy. It travels in waves (thanks to electric and magnetic fields)
- 15. Light is also called Electromagnetic Radiation
- 16. QUANTUM PHYSICS You and everything around you is made up of quantum physics
- 17. - one confusing thing about quantum physics is how to picture an electron -it seems to be a wave until you measure it and then it is a particle Quantum Physics
- 18. Question! So what is actually an electron?
- 19. Answer! It is both. This phenomena is known as particle-wave duality.
- 20. Video of the Day The Double-Slit Experiment
- 21. -apart from huge explosions, radiation also applies to rainbows and a doctor examining an x-ray -energy that travels and spreads out -has electric field and magnetic field associated with it Radiation
- 23. Answer! Force that causes things to move
- 24. 2 Scientific Phenomena Electromagnetic Radiation - pure energy with interacting electrical and magnetic waves 1.
- 25. Everything around us is shaped by sending and detecting electromagnetic radiation .
- 26. 2 Scientific Phenomena 2. Nuclear Radiation - originates in the atomic nucleus. It is energy released as high-speed charged particles or EM waves.
- 27. Some combinations of protons and neutrons known as isotopes remain unstable or radioactive .
- 28. Question! What is an isotope?
- 29. Answer! Two or more elements that contain equal numbers of protons but different numbers of neutrons
- 30. Sometimes, an atom will have too many or too few neutrons. when this happens, it becomes unstable or "radioactive" .
- 31. FOR EXAMPLE, TWO EXTRA NEUTRONS IN A HYDROGEN ATOM CREATES TRITIUM. STUFF THAT MAKES SAFETY SIGNS GLOW IN THE DARK!
- 32. Question! Who was a pioneer in researching radioactivity?
- 34. -Radioactive atoms want to become stable again so they release energy until they get back to a balanced state. This process is known as radioactive decay. Radioactivity
- 35. 3 Main Types of Radiation Alpha Particles - made up of two protons and two neutrons which is exactly the same as the nucleus of a helium atom. These particles don't have any electrons so they have an overall charge of 2 + from those two positive protons. 1.
- 36. 3 Main Types of Radiation 2. Beta Particles - just electrons. They have a charge of minus 1 and has no mass. Weird thing about an electron is that it came from a nucleus that decays into a proton and electron.
- 37. 3 Main Types of Radiation 3. Gamma Rays - are not particles; they are waves of EMR. They have very short wavelengths and travel with the speed of light.
- 40. Answer! They are created as a result of vibrations between a magnetic field and electrical field
- 42. -treatment of cancer -does not work in an instant -cancer cells can take up to a few months to die Radiotheraphy
- 43. -can pass through skin -bones and other structures cast shadows -similar to holding a pen behind a piece of paper in front of a light X-Rays
- 44. X-Rays
- 45. -to determine the ages of fossils -when an organism dies, its carbon-14 will begin the process of radioactive decay Carbon Dating