GEOPHYSICAL SCIENCE Introduction to Scientific Processes.

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1 GEOPHYSICAL SCIENCE Introduction to Scientific Processes

2 What is Geophysical Science  Geophysical Science (Earth Science) has four major branches: –Geology –Astronomy –Meteorology –Oceanography What does each branch study?

3 Earth System Science  We will be looking at the details of the four branches while seeing how the four “spheres” interact.  Making a change in one “sphere” will influence another sphere.  This relationship between the spheres and the study of their interactions is called Earth System Science.

4 What are “Spheres”?  The Four Major “Spheres”: –Atmosphere-mixture of gasses that surrounds the planet –Biosphere- where life exists on Earth –Hydrosphere- part of Earth that is water –Lithosphere (geosphere)- solid outter crust of the Earth

5 Earth’s Matter Moves Through…  Earth is a closed system in terms of matter.  Matter moves between the different spheres.  As it moves through different spheres it can change form (from one compound to another) or state of matter (from a liquid to a solid, or a liquid to a gas)

6 Observation  Observation is contact with the world through the use of the senses.  Different observers exposed to the same sense do not necessarily see, hear, feel, taste or smell the same things.

7 Inference  We draw inferences on the basis of observations, or on conclusions drawn from previous observations.  Inference is the interpretation of facts. (Inference is similar to an assumption)  Inferences express probability, not certainty.

8 The Scientific Method 1.Ask a Question. Come up with a question that you will attempt to answer through your experiment. Make sure you phrase it as a question! Example: What effect does Dissolved Oxygen (DO) have on the abundance of aquatic life such as fish?

9 2.Gather Information. Do some research on the topic of your study. Use books, the internet, peers, and personal knowledge to provide some background information. Also include information if anyone has ever done this experiment before and, if so, what their results were. Example: Dissolved Oxygen (DO) is essential for the maintenance of healthy lakes and rivers. The presence of oxygen in water is a positive sign of a healthy body of water but the absence of oxygen is a signal of severe pollution. Rivers range from high to very low levels of dissolved oxygen - so low, in some cases, that they are practically devoid of aquatic life.

10 3.Make a Hypothesis. Come up with a prediction, or an informed statement, that answers the question you asked (usually if/then format). Example: If DO is an important part of the survival of aquatic life, then streams with higher levels of DO will have more abundant aquatic life than those with lower levels of DO. * Do not use “I think …” or “Maybe…” This is your prediction … make it a strong statement. It’s okay if it is wrong.

11 4. Perform the Experiment. List the procedure that you will follow (along with the materials used) to do the experiment. Example: 1.Obtain samples from two different water sources from approximately the same time of the day. 2.Test each sample for the amount of DO present. 3.Repeat the test for 5 consecutive days. 4.For each test day, do a sample survey of the amount of aquatic life visible at that time, for each water source. 5.Record results for each days tests in a data table

12 Variables in an Experiment  The best way to perform an experiment is to limit the number of variables. The fewer the variables the more meaningful the results.  However, every experiment will at least have two variables: –The Independent Variable – The one the experimenter manipulates. –The Dependent Variable – The one that is affected by the independent variable, and not directly controlled by the experimenter (the dependent variable depends on the independent variable).

13 Name That Variable!!!  In the example provided, what is the… –Independent Variable? The DO level was the quantity which was chosen by the experimenter to test. –Dependent Variable? The amount of aquatic life is not controlled by the experimenter. –The amount of aquatic life present is directly dependent upon the amount of dissolved oxygen (not the other way around).

14 More Variables!!  Can blueberries slow down aging? A study indicates that antioxidants found in blueberries may slow down the process of aging. In this study, 19-month old rats (equivalent to 60-year old humans) were fed either their standard diet or a diet supplemented by either blueberry, strawberry, or spinach powder. After eight weeks, the rats were given memory and motor tests. Although all supplemented rats showed improvement, those supplemented with blueberry powder showed the most notable improvement.

15 What is the independent variable? Diet (blueberries, etc…) What is the dependent variable? Test Results

16 Control Groups  In order to test a variable in an experiment, a comparison must be made to whatever has not been subjected to the variable. This is referred to as a control, or control group.  In order to have a controlled experiment, you must have a control group.  The group that receives the variable, is the experimental group.  What is the control group from the previous example? Control Group: Rats fed a standard diet!

17 5.Collect and Analyze Data. Data is always collected in a table or chart. Data is always presented in a graph. (line or bar) more to come on this! Example of a data table  Example of a line graph 

18 6.Make a Conclusion. Your conclusion must do two important things – 1) Explain in words what your graph shows and 2) State whether your results did or did not support your hypothesis. Example: The data that was collected from both rivers was done in the same manner, at the same approximate time of day, during the same time of the year. The results show that my hypothesis was correct. More aquatic life was observed in the water source where higher levels of Dissolved Oxygen were measured. The opposite was true for the water source that had lower levels of DO, it had fewer numbers of aquatic life observed.

19 7.Communicate your findings. Write up a lab report in which you address each step of the scientific method. Be sure to include graphs and tables when needed. Your report should follow the steps in the same order as we have covered them.

20 An Easy Way to Remember the Scientific Method… Queens In Heels Eat Delicious Chocolate Cake!!! Queens= question In= information Heels= hypothesis Eat= experiment Delicious= data Chocolate= conclusion Cake= communicate

21 Theory  Ideas or phenomenon that have been tested many times (and many observations have been made) are often given explanations.  These explanations, found in many observations and experiments, are called theories. Theories must be supported by a great deal of evidence.

22 Graphing Data  When setting up a graph it is important to keep in mind that a graph is a visual picture of the data.  LOOKS COUNT when it comes to graphing.  Appropriate graphs that are scaled correctly and neatly are excellent tools for analyzing results.

23 Graphing Guidelines 1. Title your graph – make an appropriate title for what is being represented. 2. Label axes – leave space for labeling each axis, including units. 3. Always plot the independent variable (control) on the horizontal (x) axis. 4. Choose an appropriate scale – make sure that each box on each axis is given the same value(1,2,5,10) and that the data will fit on the paper according to your scale, but at the same time, be visually pleasing.

24 Line vs. Bar  In this class you will be using either a line, or a bar graph, but how do you know when to use which graph?  Use a line graph when a there is a direct correlation between the two variables being plotted.  Use a bar graph when the two variables are not directly correlated.

25 Measurement  Measuring and measurement tools are an essential part of the scientific process.  The International System of Units (SI), also called metric system, will be used in this class and in most science classes.

26  Prefixes:  micro (µ)- means 1/1,000,000  milli (m)- means 1/1,000  centi (c)- means 1/100  deci (d)- means 1/10  deca (dk)- means 10  hecto (h)- means 100  kilo (k)- means 1,000  mega (M)- means 1,000,000

27 Accuracy  Accuracy indicates how close a measurement is to the accepted value

28 Precision  Precision indicates how close together or how repeatable the results are.  Precision indicates how close together or how repeatable the results are.

29 Experimental Error There are many potential sources of error when designing and carrying out experiments. Errors can arise from: 1.Instrument error: Calibration of the instrument has not been carried out or is faulty. Consequently, accuracy and precision are affected. 2.Personal error: Observer making inaccurate observations. These type of errors can be overcome by taking an average based on several measurements, especially if data is collected by two or more independent observers. This overcomes the problem of personal bias resulting from poor observational habits which might produce a consistent observational error if only one investigator collects the data. 3.Sampling errors: These can also arise because of the size or nature of the sample used. Sample sizes can be either too small or not random enough. Replication of experiments also reduces errors.

30 Error Analysis One way to analyze experimental error is with a % error calculation. The % error is useful when you have a single experimental result that you wish to compare with a standard value. Utilize the following calculation: Expt # = experimental # (# you got) Std. # = standard # (accepted/correct #)

31 Sample Problem The accepted density value for Titanium is 4.5g/ml. Johnny measured Titanium’s density and received a value of 4.2g/ml. What is the percent error in his measurement? 4.2 – 4.5 x 100 = 6.7% is the percent error 4.5 NOTE: A 0% error means you got the correct accepted value. The larger the percent error value, the farther away you are from the accepted value.

32 Metric Conversions  To convert in the metric system is simply an exercise in moving the decimal place.  First you must know the prefixes and their order. base unit base unit  K ilo H ecto D eca ( l,g,m ) D eci C enti M illi K ing H enry D ied by D rinking C hocolate M ilk l = liters (unit of volume)g = grams (unit of mass) m = meters (unit of distance)

33 Conversion Practice  567 g = __________ mg  78 L = ___________ Kl .0078 Km = _______ cm 567.000 0.078 780

34 Density  The amount of matter (mass) in a given space (volume) –Density describes how tightly packed the molecules in a substance are. –Density = mass/volume More DENSE Less DENSE

35 Problem Solving  In this class you will be asked to solve some problems from time to time using some equations and calculations.  To give you a way of organizing your information, I would like you to use this four step method to solve all problems in this class.

36 Four Step Problem Solving Method 1. Read the Problem and list the information given (knowns and unknowns). 2. Show the formula you will use to solve the problem. 3. Solve the problem – show your work with units included. 4. Show your answer with the correct number of decimal places, or a whole number. It is extra important that your answer also includes units. Include a circle or a box around your final answer.

37 Problem Solving Practice 1. WHAT IS THE DENSITY OF AN OBJECT THAT HAS A VOLUME OF 14.3 mL, AND A MASS OF 20.0 g? Knowns/UnknownEquationShow workAnswer/units D=M/V M=20.0g V=14.3 ml D=? D=20.0g/ 14.3 ml D= 1.4 g/ml

38 2. WHAT IS THE MASS OF AN OBJECT THAT HAS A VOLUME OF 2.0 mL, AND A DENSITY OF 10.4 g/mL? Knowns/UnknownEquationShow workAnswer/units M=D*V D=10.4 g/ml V=2.0 ml M=? M=10.4 g/ml * 2.0 ml M=20.8 g

39 3. WHAT IS THE VOLUME OF A GAS THAT HAS A MASS OF 0.025 g, AND A DENSITY OF 0.007 g/mL? Knowns/UnknownEquationShow workAnswer/units V=M/D M=0.025 g D=0.007 g/ml V=? V=0.025 g/ 0.007 g/ml V=3.6 ml