Chapter 3 – Models of Earth & Chapter 4 – Earth’s Chemistry

1. Chapter 3 – Models of Earth & Chapter 4 – Earth’s Chemistry

2. Reference Points on Maps -Geographic Pole • The points at which Earth’s axis of rotation intersects Earth’s surface are used as reference points for defining direction. • These points are the geographic North Pole and South Pole.

3. Equator • Halfway between the poles, a circle called the equator divides Earth into the North and Southern Hemispheres. • A reference grid that is made up of additional circles is used to locate places on Earth‘s surface.

4. Latitude • One set of circles describes positions north and south of the equator. • These circles are known as parallels, and they express latitude.

5. Latitude • Parallel any circle that runs east and west around Earth and that is parallel to the equator; a line of latitude. • Latitude the angular distance north or south from the equator; expressed in degrees.

6. Latitude of the Poles • Latitude is measured in degrees, and the equator is 0° latitude. The latitude of both the North Pole and the South Pole is 90°.

7. Meridian • East-west locations are established by using meridians. • A meridian is any semicircle that runs north and south around Earth to form East and West Locations. • It is a line of longitude.

8. Longitude • Longitude the angular distance east or west from the prime meridian; expressed in degrees. • The meridian that passes through Greenwich, England is called the prime meridian. • This meridian represents 0° longitude.

9. Royal Observatory

10. Longitude • The meridian opposite the prime meridian, halfway around the world, is labeled 180°, and is called the International Date Line.

11. Longitude

12. The Global Positioning System • GPS is a satellite navigation system that is based on a global network of 24 satellites that transmit radio signals to Earth’s surface.

13. The Global Positioning System • A GPS receiver held by a person on the ground receives signals from three satellites (the same method as earthquakes known as triangulation) to calculate the latitude, longitude, and altitude of the receiver on Earth. • http://electronics.howstuffworks.com/gadgets/travel/gps.htm • https://www.youtube.com/watch?v=vVX-PrBRtTY

14. Lesson 3.2 Topographic Maps • One of the most widely used maps is called a topographic map, which shows the surface features of Earth. • Topographythe size and shape of the land surface features of a region. • Elevationthe height of an object above sea level.

15. Advantages of Topographic Maps • One of the advantages to using a topographical map is that it shows the three dimensional lay of the land. • It does this by using contour lines.

16. Contour Lines • On topographic maps, elevation is shown by using contour lines. • Contour line Is a line that connects points of equal elevation on a map.

17. Contour Interval • The difference in elevation between one contour line and the next is called the contour interval. • Every fifth contour line is darker than the four lines on either side of it. • This index contour makes reading elevation easier.

18. Spacing of Contour Lines • The spacing and direction of contour lines indicate the shapes of the landforms represented on a topographic map. • Closely spaced contour lines indicate that the slope is steep. • Widely spaced contour lines indicate that the land is relatively level.

19. Valley on Contour Maps • A contour line that bends to form a V shape indicates a valley. • The V always points upstream, (upside down in the picture) or in the direction from which the water might flow.

20. Hilltops on Contour Maps • Contour lines that form closed loops indicate a hilltop.

21. Hilltops on Contour Maps • Closed loops that have short straight lines perpendicular to the inside of the loop indicate a depression.

22. Chapter 4 – Chemistry of Earth - Distinguishing Properties • All matter has two types of distinguishing properties—physical properties and chemical properties. • http://www.youtube.com/watch?v=92Mfric7JUc&feature=related – potassium in trashcan at school • https://www.youtube.com/watch?v=RAFcZo8dTcUsodium in a school pond • http://www.youtube.com/watch?feature=fvwp&v=MTcgo46nxNE&NR=1sodium in a pond (do this first) doesn’t occur naturally it is ion on Earth

23. Physical Properties • Physical properties are characteristics that can be observed without changing the composition of the substance. • Physical properties include density, color, hardness, freezing point, boiling point, and the ability to conduct an electric current.

24. Chemical Properties • Chemical properties are characteristics that describe how a substance reacts with other substance to produce different substances.

25. Theory of Atoms • By the early 20th century, there was rather compelling evidence that matter could be described by an atomic theory - atoms.  • In 1897, J.J. Thomson showed that electrons have negative electric charge and come from ordinary matter.

26. Atoms • For matter to be electrically neutral, there must also be positive charges lurking somewhere. • The breakthrough came in 1911 when Ernest Rutherford conducted an experiment intended to determine the angles through which a beam of alpha particles (helium nuclei) would scatter after passing through a thin foil of gold.

27. Atoms • The majority of alpha particles hardly scattered at all - But there were alpha particles that scattered through angles greater than 90 degrees.

28. Model of an Atom • The only model of the atom consistent with this Rutherford experiment is that a small central core (the nucleus) houses the positive charge and most of the mass of the atom. • While the majority of the atom’s volume contains electrons orbiting the central nucleus.

29. Atoms • The atom is the most basic unit of matter and consists of three types of subatomic particles—protons, electrons, and neutrons. Au (79) – using a scanning tunneling microscope

30. Atomic Nucleus • The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons.

31. Proton • Proton a subatomic particle that has a positive charge and that is located in the nucleus of an atom. • The number of protons determines the identity of the element.

32. Neutron • A neutron is a subatomic particle that is located in the nucleus of an atom and has no charge. • Neutrons and protons are almost exactly the same size and mass and form the nucleus of an atom.

33. Electron • An electron is a subatomic particle that has a negative charge and is found outside of the nucleus. • Electrons are much smaller than neutrons and protons -The mass of a proton is 1840 times greater than the mass of an electron. • A neutral atom has equal numbers of electrons and protons.

34. The Electron Cloud • The electrons of an atom move in a certain region of space called an electron cloud that surrounds the nucleus. • The charge of a proton and an electron are equal in magnitude, yet opposite in sign. • They are electrically attracted to each other and this attraction holds electrons in the atom.

35. Atomic Mass • The atomic mass of an element it determined by the amount of protons and neutrons in its nucleus. • The mass of a subatomic particle is too small to be expressed easily in grams, so a special unit called the atomic mass unit (amu) is used. • https://www.youtube.com/watch?v=DYW50F42ss8 • Potassium- http://www.youtube.com/watch?v=pPdevJTGAYY&src_vid=Jy1DC6Euqj4&feature=iv&annotation_id=annotation_728808

36. Lesson 4.2 - Isotopes • Although all atoms of a given element contain the same number of protons, the number of neutrons may differ.

37. Isotopes • Isotope is an atom that has the same number of protons (or the same atomic number) as the other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass).

38. Isotopes • Because of their different number of neutrons and their different masses, different isotopes of the same element have slightly different properties.

39. Radioactive Carbon Isotope • Carbon-12, carbon-13 and  carbon-14 are three isotopes of the element carbon. • The atomic number of carbon is 6 which means that every carbon atom has 6 protons, so that the neutron numbers of these isotopes are 6, 7 and 8 respectively.

40. Radioactive Carbon • Of the three naturally occurring isotopes of carbon on Earth: 99% of the carbon is carbon-12, 1% is carbon-13, and carbon-14 occurs in trace amounts. • The half-life of carbon-14 is 5,730±40 years. 

41. Radioactive Carbon • The primary natural source of carbon-14 on Earth is found in the atmosphere. • Ultraviolet radiation creates radioactive Carbon-14 (6 protons and 8 neutrons) which then decays back into nitrogen-14 (7 protons and 7 neutrons) through beta decay.

42. Radioactive CarbonDating • Consumed by organic materials, its presence is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949), to date archaeological, and geological samples.

43. Radioactive UraniumDating • An example of a naturally occurring isotope is uranium-238. • It decays through a series of steps to become a stable form of lead.

44. Radioactive CarbonDating • Uranium-lead dating is usually performed on the mineral zircon. • It is used on older matter because it has the longest half-life of 4.5 billion years.

45. Average Atomic Mass • Because isotopes of an element have different masses, the periodic table uses an average atomic mass of each element.

46. Periodic Table • The periodic table is based on the Periodic Law which states that the physical and chemical properties of the elements recur in a systematic and predictable way when the elements are arranged in order of increasing atomic number. • Elements in the periodic table are arranged in periods (rows) and groups (columns).

47. Periodic Table • Each of the seven periods is filled sequentially by atomic number. • Groups include elements having the same electron configuration in their outer shell, which results in group elements sharing similar chemical properties.

48. Elements • As of November 2011, 118 elements have been identified, the latest being ununseptium in 2010. • Of the 118 known elements, only the first 92 are known to occur naturally on Earth.

49. Atoms • Hydrogen and helium are by far the most abundant elements in the universe. • However, iron is the most abundant element (by mass) making up the Earth, and oxygen is the most common element in the Earth's crust.

50. Valence Electrons • The electrons in the outer shell are termed valence electrons. • Valence electrons determine the properties and chemical reactivity of the element and participate in chemical bonding.