Scientific method and si units


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Scientific method and si units

  1. 1. Scientific Method<br />
  2. 2. Scientific Method<br />Systematic approach used in scientific studies<br />A logical approach to solving problems by observing and collecting data, formulating a hypothesis, testing a hypothesis, and formulating theories that are supported by data<br />
  3. 3. Scientific Method<br /><ul><li>Process used by scientists (everyone/anyone) to determine a solution.
  4. 4. “Method” means there is a consistent and reproducible way of doing something
  5. 5. If you need to determine a solution then you must havea problem.</li></li></ul><li>Steps of the Scientific Method<br /><ul><li>Hypothesis
  6. 6. Data</li></ul>Make observations and state the problem<br />2. Gather information about the problem<br />3. Form a hypothesis<br />Suggested solution to the problem<br /><ul><li>Not educated guess because use information from step 2</li></ul>4. Design/conduct an experiment<br />5. Gather/analyze data<br />information from an experiment<br />6. Form conclusion based on data and determine whether hypothesis was correct or incorrect with support data<br />
  7. 7. Steps of the Scientific Method<br />• Observation<br />• Problem Statement <br />• Hypothesis Statement<br />• Experiment / Data Collection<br />• Conclusion Statement<br />
  8. 8. Steps of the Scientific Method<br />
  9. 9. Types of Observation<br />Qualitative Data and observations (QL)<br />Color, shape, odor, or other physical characteristics<br />Quantitative Data and observations (QN)<br />Numerical information such as temperature, pressure, volume, the quantity of a chemical formed<br />
  10. 10. Make Observations!<br />Qualitative Observations<br />Color<br />Smell<br />Texture<br />Shape<br />Anything regarding the Appearance<br />Quantitative Observations<br />Length<br />Volume<br />Mass<br />Temperature<br />Speed<br />Density<br />Any type of measurement<br />
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  14. 14. (PS)<br />
  15. 15. Variable<br />What does variable mean?<br />To change…<br />
  16. 16. Variables<br />Independent Variable (IV)<br />aka manipulated variable<br />Only ONE!!!<br />The one the INDividual (YOU) physically change/manipulate<br />Dependent Variable (DV)<br />aka the responding variable<br />Only ONE!!!<br />The one that changes (or you hope will change) when you change the IV<br />The one you are collecting data about/measuring<br />Constant Variables<br />MANY of these<br />All the things you want to keep the SAME (do NOT change)<br />
  17. 17. Variables<br />You should be able to identify the IV and DV from your PS!!!!<br />
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  20. 20. Formula: <br />If…(state what will be done to the IV), then…(state what is predicted to happen to the DV)<br />
  21. 21. CLASS WORKName That Variable!Control (1):Constants(2) :Independent (1): Dependent (1):Hypotheses (1):<br />1. An experiment that tests how quickly different temperatures will dissolve sugar cubes. <br />2. An experiment that explores how different colors of light impact plant growth. <br />3. How does the temperature of a chemical reaction change over time? <br />
  22. 22. Experiment<br />a planned way to test a hypothesis and find out the answer to the problem statement.<br />a way to collect data and determine the value of the DV.<br />compares the IV to the DV.<br />can only test one DV at a time and change one IV at a time<br />
  23. 23. Experiment<br />Variables <br />Materials and Procedures<br />Data and Results Section<br />Include observations (QL and QN)<br />Pictures/tables/graphs/calculations <br />
  24. 24. Why Do We Use Graphs? <br />Graphs help us visualize numerical data.<br />•There are several different types of graphs:<br />Bargraphs: compare multiple objects<br />Piegraphs: shows relationships of parts to a whole<br />Linegraphs: show the relationship between 2 variable<br />
  25. 25. Types of Relationships (between variables)<br />Direct: as x increases y increases<br />Indirect: as x increases y decreases<br />Constant: as x increases y remains the same<br />
  26. 26. Problem<br />A suggested solution to the problem Gathering<br />
  27. 27. Conclusion Statement <br />Do NOT use 1st person <br />Me, my, I, we, our, etc…<br />VERY Objective<br /> a summarization that presents the findings of the experiment, what the data shows, and states if the hypothesis was correct (supported) or incorrect (negated)<br />Restate PS<br />Restate HYP<br />Summarize M&P<br />Analyze and explain data/results (tables, observations, pictures)<br />State whether HYP was correct or not and EXPLAIN why<br />Explain possible errors<br />Explain ways to improve experiment/research<br />Explain APPLICATION to biology and society <br />
  28. 28. After we accept a hypothesis, experiment, and draw a conclusion…<br />Many conclusions that support each other make up a THEORY<br />Explanation supported by many, many conclusions<br />Many conclusions that support each other over a period of time<br />Atomic Theory<br />Theory of Relativity<br />CAN be DISPROVEN<br />“The world is flat”<br />SCIENTIFIC LAW<br />A relationship in nature that is supported by many, many experiments<br />No exceptions<br />Law of Gravity<br />
  29. 29. At least 3 trials..<br />Accuracy<br />How close to a measured value a measurement is<br />capable of providing a correct reading or measurement<br />'correct'<br />A measurement is accurate if it correctly reflects the size of the thing being measured.<br />Precision<br />Ability to get the same value more than once (regardless of it is the right value or not)<br />exact, as in performance, execution, or amount<br />repeatable, reliable, getting the same measurement each time<br />
  30. 30. This is a precise pattern, but not accurate. The darts are clustered together but did not hit the intended mark. <br />This pattern is both precise and accurate. The darts are tightly clustered and their average position is the center of the bull's eye. <br />This is a randomlike pattern, neither precise nor accurate. The darts are not clustered together and are not near the bull's eye. <br />This is an accurate pattern, but not precise. The darts are not clustered, but their 'average' position is the center of the bull's eye. <br />
  31. 31. SI Units<br />In science, we need to speak the same language<br />1795<br />French scientists develop metric system<br />1960<br />International committee meets to update the system and names it the “SystemeInternationaled’Unites” aka SI <br />
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  33. 33. SI Base Units<br />Seven SI base units<br />Base unit<br />A defined unit in a system of measurement that is based on an object or event in the physical world<br />
  34. 34. Tools of the Trade<br />Mass Scale that measures GRAMS not POUNDS<br />Pounds are used to measure the force of gravity on your mass…we want to measure the amount of STUFF (Matter) in a thing<br />Temperature thermometer measures the kinetic energy (KE) /movement of particles<br />Faster moving particle=more (KE)=higher temp (HOT)<br />Slower moving particles=less (KE)=cooler temp (COLD)<br />Volume amount of space object takes up…<br />ruler, measuring tape, etc to measure meters3 (l x w x h)<br />OR graduated cylinder to measure LITERS<br />Measure volume at the MENISCUS (curve or dip in the water)<br />
  35. 35. Temperature<br />SI unit?<br />Kelvin<br />Our thermometers measure Celsius<br />To convert from Celsius to Kelvin<br />0o C + 273 = 273 K<br />To convert from Kelvin to Celsius<br />373 K - 273 = 100o C<br />
  36. 36. SI Derived Units<br />Not all quantities can be measured with base units<br />More than one base unit can be used<br />Speed limit is measure in….<br />MPH<br />Miles per hour<br />Which is a combo of what base units?<br />Length and time<br />
  37. 37. Derived Units<br />
  38. 38. Common derived units we will use<br />Speed<br />Base unit of length and base unit of time<br />Meters/second<br />Volume<br />3 base units of length<br />Length x length x length<br />1 cm3 = 1 mL<br />Density<br />Mass/volume<br />Ratio that compares mass of an object to its volume<br />g/cm3 or g/mL<br />
  39. 39. Density<br />Density=mass divided by the volume<br />D=m/V<br />Gram/L or grams/m3<br />How do we figure out volume of odd shaped objects…say a paper clip?<br />Water Displacement<br />What happens when you fill up the bath tub to the rim and then get in?<br />
  40. 40. Archimedes Principle<br />Measure known amount of water in graduated cylinder and record VOLUME (mL)<br />This is initial volume (Vi)<br />Drop in odd shaped object (paper clip)<br />Record the NEW volume of water<br />This is final vlume (Vf)<br />Subtract Vi from Vf to get volume of object (Vo)<br />Vo = Vf- Vi<br />Get the mass of the paper clip form the scale<br />Plug the mass (g) and volume (L) into density formula to figure out the density of the paper clip<br />
  41. 41. Class Work!<br />Suppose a sample of aluminum is placed in a 25 mL- graduated cylinder containing 10.5 mL of water. The level of water rises to 13.5 mL. Mass is 25 g. What is the density of the aluminum sample?<br />What is the volume of a sample that has a mass of 150 g and a density of 5 g/mL?<br />
  42. 42. Prefixes Used with SI units<br />
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  44. 44. Kids Hate Doing Math Dittos Christmas Morning<br />King Henry Died Monday Drinking Chocolate Milk<br />
  45. 45. Do you know this number, 300,000,000 m/sec.? <br />Do you recognize this number, 0.000 000 000 753 kg. ? <br />There has to be an easier way to write these numbers….<br />
  46. 46. Scientific Notation<br />Easy way to write very BIG or verysmallnumbers<br />Uses exponents<br />a shorter method to express very large or very small numbers<br />Scientific Notation is based on powers of the base number 10. <br />
  47. 47. The number 123,000,000,000 in scientific notation is written as : <br /> 1.23 x 1011<br />The first number 1.23 is called the coefficient. <br />It must be greater than or equal to 1 and less than 10.<br />The second number is called the base . <br />It must always be 10 in scientific notation. <br />The base number 10 is always written in exponent form. <br />In the number 1.23 x 1011 the number 11 is referred to as the exponent or power of ten. <br />
  48. 48. To write a number in scientific notation…<br />Put the decimal after the first digit and drop the zeroes<br />123,000,000,000<br />Add 10 and your exponent<br />Your exponent is however many places you had to move the decimal <br />Exponent is positive or negative<br />If the # is VERY small…<br />The exponent will always be NEGATIVE<br />If the # is VERY BIG…<br />The exponent will always be POSITIVE<br />
  49. 49. Scientific Notation Tips<br />If the # is VERY small…<br />The exponent will always be NEGATIVE<br />If the # is VERY BIG…<br />The exponent will always be POSITIVE<br />
  50. 50. Examples<br />Write 124 in scientific notation<br />Write 0.000 000 000 043 6 in scientific notation<br />Convert 0.000 000 005 78 to scientific notation<br />Convert 93,000,000 to scientific notation<br />Write in decimal notation:  3.6 × 1012<br />Convert 4.2 × 10–7 to decimal notation<br />