2 ScienceScience is a process that uses observation and investigation to gain knowledge about events in nature.Major categories:Life scienceLiving thingsEarth ScienceEarthSpacePhysical ScienceMatterEnergy
3 Investigating our World Scientists learn new information about the natural world by performing investigations.Can be done in a variety of ways:Observing and recordingExperimentsUsing ModelsThe Scientific Method described the procedure commonly followed in scientific investigations
4 Scientific Method Six common steps used in investigation State the ProblemGather InformationForm a hypothesisTest the hypothesisAnalyze DataDraw conclusionsNot all steps will be used every timeSome steps may be repeatedSome new steps may be addedThe scientific method is not a rigid process
5 Let’s break it down… Stating the problem State the problem in a form of a questionMake sure the question asks something that is testable
6 Testable Questions Why do people ask questions? To a scientist, what do you think makes a good question?What types of questions do you think aren’t suitable for scientific investigation?
7 Let’s Break it Down… Researching and Gathering information Research is necessary to formulate a reasonable hypothesisSources of information:TextbookArticlesExpertReference booksObservations
8 Let’s break it down…(cont) Forming a hypothesisMake an educated guess to answer the question you are investigatingScientists frequently create a hypothesis with little or no informationAs data is collected, a hypothesis is often refinedTesting the hypothesisExperiments or observationExperimentsHave only 1 independent variableAll other variables are held constant
9 Let’s Try That…An experiment is set up to determine what factor causes the greatest amount of liquid to evaporate.Three containers of the same size each contain 100 mL of boiling water.One container is steel, one is brass, and the third is aluminum.The containers are allowed to sit for 20 minutes.What is the independent variable?How many controlled factors are there?
10 Let’s break it down…(cont) Analyzing DataUsing tables and chartsShare data with othersDraw conclusionsDoes the data support the hypothesis?What do I need to do now?Rules of Thumb:Don’t jump to conclusionsThe simplest solution is usually correct
11 Now we’ll put it all together… In 1912, farmers in California found that it was cheaper to pick all the oranges at once regardless of whether they were ripe.The oranges were placed in a small room heated with kerosene lamps and the oranges would ripen in a few days.At some point, the farmer used an electric heater instead of kerosene lanterns. The oranges no longer ripened.When switching back to kerosene, the oranges ripened.This was found to be true of other citrus.The farmers wondered what was so special about the kerosene lanterns?
12 Here we go… What is the question? What type of research would you do? Design an experiment.What is the independent variable?What are the controlled factors?Analyze the resultsDraw a conclusion
13 ObservationsTest Your Observation SkillsM&M LabVariables Worksheet
14 Visualizing with Models Sometimes when observing something that is too large, too small, or too time consuming, we need to use modelsModels have been used frequently throughout history.Models can be something you can touch or many models are created using computers.Dams and LeveesCowpea Mosaic Virus
15 Scientific Theories and Laws A theory is an explanation of things or events based on knowledge gained by many observations and investigationsStrongly supported hypotheses can become theoriesScientific Laws are statements of what happens in natureLaws do not offer explanation as to whyTheories Explain Laws!
16 Standards of Measurement SI (International System of Units) is the share language for measurement in scienceBased on the metric systemUses multiples of 10Each type of measurement has a base unitLengthmeterMasskilogramTimesecondElectric currentampereTemperaturekelvinAmount of a substancemoleIntensity of lightcandela
17 SI PrefixesThe SI base units are not always of convenient size for a particular measurement.The meter would be too big for reporting the thickness of this pageThe meter would be too small for the distance from Chicago to DetroitSI includes a series of prefixes, each of which represents a power of 10.These allow us to reduce or enlarge the SI base units to convenient sizes.
18 Conversions A box weighs 1.25 kg. How many grams is that? Metric Conversion LadderA box weighs 1.25 kg. How many grams is that?Kilogram (kg) is larger than gram (g)You need to multiply (shift decimal to the right)3 steps (3 zeros)1.25 x 1000 = 1,250 grams
20 Measuring DistanceChoose a unit of length that is appropriate for what you are measuringFor example,cm for length of pencilm for length of classroomHelps avoid using large digit numbers
21 Remember: You have to multiply the numbers AND the units Measuring VolumeThe amount of space an object occupies is volume.Measure length, width, and height and multiply the three numberslength x width x height = volumeExample: 10 cm x 10 cm x 10 cm = 1000 cm3Remember: You have to multiply the numbers AND the unitsLiquid volume is often measured in liters1 mL = 1 cm31000 cm3 is 1000 mL
22 Measuring Matter Matter is anything that has mass and takes up space. To measure mass, we use mass and volume.Mass and volume can be expressed as a ratio called densityDensity is a combination of two SI units.Combining two or more SI units results in a derived unit.Can you think of other examples?
23 Accuracy and Precision Accuracy is how close a measured value is to the actual (true) value.CorrectnessPrecisionPrecision is how close the measured values are to each other.Repeatability
24 Communicating with Graphs Scientists often use graphs and charts to display their result in order to better identify patternsGraphs are useful for displaying numerical information.Different graphs are useful for different types of informationLine GraphBar GraphCircle Graph
25 Line GraphsLine graphs are useful whenever a dependent variable is changing due to a change in a independent variableDependent variables are y-axisIndependent variable are the x-axis
26 Bar GraphsBar graphs are useful for comparing information collected by counting.
27 Circle GraphsCircle graph, or pie charts, are use to show how some fixed quantity is broken downThe pieces of the pie represent a percentage of the total