Historical Perspectives and Scientific Revolutions

1. Historical Perspectives and Scientific Revolutions OGT Review By Elizabeth Buckholtz Woodward High School TPS Science Support Teacher

2. Atomic Theory • Democritus was first to develop idea of ATOMS. (440 BC) • Keep cutting a piece of material in half & you eventually can’t cut any more.

3. Atomic Theory • Had a hard time convincing others • 2000 yrs. later, the development and use of technology allowed scientists to build on his notion.

4. Atomic Theory • John Dalton came up with ATOMIC THEORY.

5. Atomic Theory • All matter consists of tiny particles called atoms. 2. Atoms of the same element are exactly alike. 3. Atoms of different elements can join together to form compounds.

6. Atomic Theory • Evidence later revealed atoms can be divided. • All other aspects of Daltons atomic theory are still supported and accepted by scientists.

7. Newtonian Mechanics • Sir Isaac Newton developed laws • explain the forces acting on moving objects. • Laws are known as NEWTONIAN MEHANICS

8. Newtonian Mechanics 1. an object at rest will remain at rest, an object in motion will remain in motion until acted upon by an unbalanced force. • force = mass x acceleration • every action has an equal and opposite reaction

9. Newtonian Mechanics • LAW OF UNIVERSAL GRAVITATION • Gravitational force between object is proportional to the product of their mass and inversely proportional to the square of their distance.

10. Newtonian Mechanics • Newtonian mechanics support the laws of planetary motion developed by Johannes Kepler • These laws explain how planetary objects orbit other objects in ellipses.

11. Newtonian Mechanics • Scientist continue to use these laws to make predictions and discover new information

12. Quantum Theory and Nanotechnology • QUANTUM THEORY (quantum mechanics) are a group of laws, theories & principles. • Explain the relationship between energy & mater.

13. Quantum Theory and Nanotechnology • Subatomic particles (photons & electrons) are so small scientist can not see how they move.

14. Quantum Theory and Nanotechnology • Laws of Newtonian mechanics and concept of electromagnetism help scientists make predictions about how these particles move. • Properties of small substances can be determined and applied in order to make new technological advances.

15. Quantum Theory and Nanotechnology • NANOTECHNOLOGY is the study of particles whose size range from 1 to 100 nm. (how big is it) laws of quantum mechanics ↓ predictions about how particles interact ↓ understanding of properties of substances

16. Quantum Theory and Nanotechnology • This information helps scientists make life easier • Examples scratch-resistant glass deep-penetrating cosmetics protective sunscreen fiber-optics microprocessors plastics & ceramics

17. Plastics + grocery bags, product packaging, cell phones, cars + alternative to metal (lighter & and less expensive) + one of the most widely used materials in world

18. Quantum Theory and Nanotechnology • do not break down easily • build up as trash • Nanotechnologists have made plastics that are environmentally friendly and can be recycled.

19. Quantum Theory and Nanotechnology • Ceramics are inorganic, claylike and exposed to high heat. • Hard and porous, can be modified to perform many functions. • Glass & cement

20. Nuclear Energy • Energy produced through nuclear fission can be harnessed in nuclear reactors to produce electrical power. • Reactor contains an isotope uranium-235 which releases energy as it decays.

21. Nuclear Energy + releases large amounts of energy which create electricity for millions of homes & businesses. + more U-235 available than fossil fuels + air pollutants are not releases in the reaction (unlike fossil fuels) • Risk of radiation escaping the reactor and contamination the environment. • Cost of operating power plant and storing radioactive substances is expensive.

22. Communication Technology • COMMUNICATION TECHNOLOGY allows messages to be sent over long distances • Telephones • Radio • Televisions • Internet

23. Communication Technology • Telephones • Sound waves are transmitted to a microphone • Microphone converts sound waves to an electric current • Electric current flows through the wire to the other phone. • Transducer in other phone converts electric current back into sound.

24. Communication Technology

25. Communication Technology • Cell phones • Same as phones but without wire • Phone converts sound to radio waves that are sent to cellular towers that transmit them from place to place.

26. Communication Technology

27. Communication Technology • Radio & TV • Receive electromagnetic waves sent out from TV and radio stations. • These waves include radio, light and microwaves.

28. Communication Technology

29. Communication Technology • Internet • Has had a major impact on society • Developed in 1960’s as a computer network used for the worldwide sharing of scientific data • 1989 developments made World Wide Web possible • Internet usage exploded and people from all over the world use it to communicate.

30. Communication Technology

31. Significant People & Contributions (matter) • Antoine Lavosier • First person to make a significant list of elements • Discovered that oxygen had a significant role in burning (combustion) and rusting. • John Dalton (see previous)

32. Significant People & Contributions (matter) • Gay-Lussac • Law of Common Volumes • Ratios between combining volumes of gases can be expressed in whole numbers • Dimitri Mendeleev • Arranged the 64 known elements on the periodic table

33. Significant People & Contributions (energy) • Marie Curie • Discovered radioactive elements • Albert Einstein • Theory of relativity (E=mc2)

34. Significant People & Contributions (forces & motion) • Johannes Kepler • Laws of Planetary Motion • Planets move in ellipses around the sun • Radius vector describes equal areas in equal times • The squares of the periodic times are to each other as the cubes of the mean distances. • Isaac Newton (see previous notes)

35. New Ideas • Are limited by the context in which they are conceived (time, available technology) • Often initially rejected by science • Sometimes come from unexpected findings • Grow slowly through contributions form many different scientists

36. OGT questions In his investigations of air, Henry Cavendish discovered a small bubble of leftover gas that would not combine with nitrogen. His observations went unnoticed until William Ramsay performed experiments in which he obtained similar results. Ramsay recalled and repeated Cavendish’s experiments exactly to verify the results. Then, using Gustav Kirchhoff’s spectroscopy technique, Ramsay was able to identify the leftover gas as the element he called argon. Upon further investigation, he found the elements neon, krypton and xenon.

37. OGT questions Based on this information, it can be said that A. the combined work of Cavendish, Kirchhoff and Ramsay led to the discovery of the noble gases. B. Kirchhoff’s work was insignificant in the investigations leading to the discovery of argon. C. Ramsay violated ethical practice in science by repeating Cavendish’s experiments. D. Cavendish is directly responsible for the discovery of argon, but not neon, krypton or xenon.