Aburto - GHHS 1 The Scientific Method and Science Process Skills What is the Scientific Method? • It is a system used in s olving pr oblems in a logical and orderly way. • Ther e is no one sci enti fic m ethod. • Scientis t combine the elements of the scientific method in a way that will best answer the question they are asking. What are Science Process Skills? • Tasks th at a scientis t mus t be a ble to do. • Thes e t asks include: –Observing - using your s enses to ga ther information. (sight, touch, hearing, & s mell but not taste) –Measuring - Quanti fying obse rvations, comparing an unknown value to a known value. –Inferring - using fact s to form conc lusions without direct observation.
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• Dependent variable (responding variable) -may change as a result of the independentvariable.
• Controlled variable – designed to remainconstant across all trials. Can be a sourceof experimental error if unaccounted for.
Identify the independent anddependent variables
1. The amount of algae growth in lakes seems to bedirectly related to the number of bags of phosphatefertilizer sold by the local merchants.
2. An investigation was performed to see if corn seedswould sprout at different times depending on thetemperature of the water in which they were placed.
3. The amount of pollution produced by cars wasmeasured for cars using gasoline containing differentamounts of lead.
• When constructing a table of data, theindependent (manipulated) variable is recordedon the left column and the dependent(responding) variable is on the right.
DependentVariable
IndependentVariable
How is a table constructed?
• Whenever units are used they are included in thecolumn heading and not listed next to eachnumber.
4050
35100
Average Diameterof Fruit (cm)
Number of LeavesRemoved
How is a table constructed?
• Data for the independentvariable is ordered fromsmallest to largest.
• This organization
establishes a pattern ofchange in theindependent variable.
• If there is acorresponding pattern ofchange in the dependentvariable, it will be easierto recognize.
• Read the paragraph and describe therelationship between the variables.
• The heights to which balls bounced whendropped from different distances weremeasured. A ball dropped 50 cm bounced 40cm high. A 10 cm drop bounced 8 cm. A ballbounced 24 cm when dropped 30 cm. Thebounce was 56 cm high for a 70 cm drop. A 100cm drop bounced 80 cm.
Why bother making tables?
• Now use the data to make a table, then describethe relationship between the variables.
• The heights to which balls bounced whendropped from different distances weremeasured. A ball dropped 50 cm bounced 40cm high. A 10 cm drop bounced 8 cm. A ballbounced 24 cm when dropped 30 cm. Thebounce was 56 cm high for a 70 cm drop. A 100cm drop bounced 80 cm.
Notice that it is easier to see the correlationbetween the variables and the 80%proportion for each bounce.
Complex Tables
• Most experiments should be repeated severaltimes.
• Repeated trials increase confidence in results byreducing the significance of chance errors thatcan occur with a single trial.
• When repeated trials are conducted, the columnfor the dependent variable is divided into smallercolumns so data can be recorded for eachrepeated trial.
title, the axis for the independentvariable, the axis for the dependent
variable, a scales (for each variable),and a legend.
What’s in a title?
• The title: depicts what the graph is about. Byreading the title, the reader should get an ideaabout the graph. It should be a concisestatement placed above the graph.
• The Independent Variable: is the variable that can becontrolled by the experimenter. It usually includes time
(dates, minutes, hours), depth (feet, meters),temperature (Celsius). This variable is placed on the Xaxis or horizontal axis.
• The Dependent Variable: is the variable that is directlyaffected by the independent variable. It is the result ofwhat happens because of the independent variable.Example: How many oxygen bubbles are produced by aplant located five meters below the surface of the water?The oxygen bubbles are dependent on the depth of thewater. This variable is placed on the Y-axis or verticalaxis.
How big do I make my graph?
• The Scales for each Variable:
• In constructing a graph one needs to know where to plot the pointsrepresenting the data.
• In order to do this a scale must be employed to include all the datapoints. This must also take up a conservative amount of space.
• It is not suggested to have a run on scale making the graph too hardto manage but it needs to be visible so not to big or small.
• The scales should start with 0 and climb based on intervals such as:multiples of 2, 5, 10, 20, 25, 50, or 100.
• The scale of numbers will be dictated by your data values.
concerning the graph's data. It should be shortand concise and placed under the graph.
• A multi-year study of the relationship betweenaverage spring temperature and the number ofpeaches produced in a small orchard suggeststhat a temperature of 83-85 ˚F results in thehighest peach output.
Try this
• Organize the following data into a table usingthe guidelines discussed:
– A study was conducted to see if the number ofpeaches on a tree was directly proportional to thenumber of leaves on the fruit tree. One tree studiedhad 87 peaches and 257 leaves. Another tree had653 leaves and 210 peaches. A third tree had 503leaves and 165 peaches. A fourth tree had 175leaves and 59 peaches. The fifth tree gave 73peaches and 219 leaves.