Ch.1: The Nature of Science

1. Ch.1: The Nature of Science

2. Contents • Earth Science • Methods of Scientists • Communicating in Science

3. 1.1: Earth Science Text ref. Ch.1.1, p.5-10

4. Objectives • Differentiate among the four major branches of Earth science. • Contrast the four systems of Earth. • Discuss how Earth science affects your daily life.

5. Obj.1: Earth Science • Earth science can be divided into four major areas • Astronomy • Meteorology • Geology • Oceanography

6. Astronomy • Is the study of objects beyond Earth’s atmosphere, including stars, galaxies, nebulae, and the formation and structure of the universe . A giant Hubble mosaic of the Crab Nebula, a supernova remnant A celestial map from the 17th century, by the Dutch cartographer Frederik de Wit.

7. What is it?

8. Answer: The Very Large Array in New Mexico, an example of a radio telescope.

9. What is it?

10. Answer: Spiral Galaxy

11. What is it?

12. Answer • Solar flare, found on the surface of the sun.

13. Meteorology • Is the branch of Earth science that studies the air that surrounds the planet. Meteorologists study the forces that occur in the Earth’s atmosphere, producing weather patterns.

14. What is it?

15. What is it?

16. Geology • The study of the materials that make up the Earth and the processes that form and change these materials is the branch of Earth science known as geology. Geologists identify rocks, study glacial movements, and interpret the 4.6 billion year history of the the Earth.

17. What is it?

18. What is it?

19. What is it?

20. Obj.2: Earth systems • There are fours main systems scientists study related to earth science. • Lithosphere • Hydrosphere • Atmosphere • Biosphere

21. The lithosphere • The lithosphere is the rigid outer shell of the planet that includes the crust and the solid, uppermost part of the of the layer below the crust, the mantle. • Continental crust: made up of granite • Oceanic crust: made up of basalt • Mantle: made up mostly of peridotite

25. Hydrosphere • The water in the earth’s oceans, seas, lakes, and glaciers, as well as the water in the atmosphere, makes up the hydrosphere. • 97% of the earth’s water exists as salt water • Remaining 3% is fresh, most of which is locked inside glaciers

26. Arctic Elephant foot glacier

27. Atmosphere • The blanket of gases that surrounds our planet is called the atmosphere. • Necessary for respiration of living things • Protects organisms from solar radiation • Moderates global temperatures • 78% nitrogen gas, 21% oxygen, remaining 1% includes water vapor, argon,carbon dioxide, and other trace gases.

28. Atmospheric Layers

29. Biosphere • The biosphere includes all organisms on Earth as well as the environments in which they live. • Most organisms exist within a few meters of the Earth’s surface. • Some organisms live in extreme conditions and temperatures, deep in the crust of the Earth or in ocean trenches. Such organisms are known as extremophiles.

30. SeaWiFS Global Biosphere September 1997 - August 1998 This composite image gives an indication of the magnitude and distribution of global primary production, both oceanic (mg/m3 chlorophyll a) and terrestrial (normalized difference land vegetation index). Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE. From en:Image:Seawifs global biosphere.jpg Primary source: http://oceancolor.gsfc.nasa.gov/SeaWiFS/BACKGROUND/Gallery/index.html

31. Obj.3: Earth science in daily life • Technological systems • GPS, satellites, communications • Weather forecasts • Early warning systems, stormtracking • Energy resources • Oil production, solar energy, geothermal, fusion technologies • Aesthetics • Beauty and natural environments

32. Methods of Science Text ref. Ch.1.2: p. 11-16

33. Definition • The Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. It is based on gathering observable, empirical and measurableevidence subject to specific principles of reasoning. A scientific method consists of the collection of data through observation and experimentation, and the formulation and testing of hypotheses

34. The Steps of the Scientific Method • Define the question • Gather information and resources (observe) • Form hypothesis • Perform experiment and collect data • Analyze data • Interpret data and draw conclusions that serve as a starting point for new hypothesis • Publish results • Retest (frequently done by other scientists)

35. STEP 1: The Question • People are naturally curious about their world. Therefore, people often ask or pose questions about natural phenomena in nature. • Why is the sky blue? • How old is the universe? • How do volcanoes work?

36. STEP 2: Gathering Research • Often the answer to a question has been previously investigated, or components of the phenomena. By conducting research, a great deal of background information may be gathered to aid in answering the initial query.

37. STEP 3: Hypothesis • The hypothesis is an educated guess about what the answer to the question might be. By “educated”, we refer to the initial background research conducted.

38. STEP 4: Experimentation • an experiment (Latin: periri, "of (or from) trying") is a set of observations performed in the context of solving a particular problem or question, to retain or falsify a hypothesis or research concerning phenomena. The experiment is a cornerstone in the empirical approach to acquiring deeper knowledge about the physical world.

39. STEP 5: Analyze the data • Data analysis is a study unto itself. Graphs, tables, charts, formulae, statistics, models, etc… are commonly used as the tools of data analysis.

40. STEP 6: Interpretation of results • This is known as the conclusion. In this step, a determination is made regarding the validity (truthfulness) of the initial hypothesis. This decision is made based on the analysis of the data from the original experiment.

41. STEP 7: Publication • After a conclusion is made regarding the hypothesis (i.e. the hypothesis is true or false), the next step is to make the information available to other scientists, readers, and the general public. Scientific journals

42. Obj. 2: Experimental variables and controls • To ensure the validity of an experiment, scientists attempt to design experiments which will test the hypothesis in question. • Variables: elements of an experiment which are being tested. • Independent variables are factors that are directly manipulated by the experimenter. • Dependent variables are factors that depend on the independent variable

43. A control is used in an experiment to determine if the results of the experiment are a result of the condition (independent variable) being tested.

44. Obj.3: Measurement • Most of us are familiar with the two primary systems of measurement. • English system: uses units such as the foot, pound, ounce, etc… • SI (Systeme International d’Unites): uses units such as the meter, liter, gram, etc…

45. The SI System • Due to the fact that the SI system is used by scientists around the world, and its ease of use in conversion, we will be using this system to quantify our observations in this course.

46. Table 1 - SI base units[2]

47. Table 2 - SI Prefixes

48. Obj.4: Scientific Notation • Scientific notation, sometimes known as 'standard notation', is a notation for writing numbers that is often used by scientists, mathematicians, and engineers to write large and small numbers. A number written in scientific notation has several properties that make it convenient to use.

49. Examples • An electron's mass is about 0.000 000 000 000 000 000 000 000 000 000 910 938 26 kg. In scientific notation, this is written 9.1093826×10−31 kg. • The Earth's mass is about 5,973,600,000,000,000,000,000,000 kg. In scientific notation, this is written 5.9736×1024 kg. • The Earth's circumference is approximately 40,000,000 m (i.e. 4 followed by 7 zeroes). In scientific notation, this is written 4×107 m. In engineering notation, this is written 40×106 m. In SI writing style, this may be written "40 Mm" ("40 megameters").

50. Communicating in Science Text ref. Ch.1.3: p.17-19