the instruc ons in your laboratory manual and these general

Custom Lab ManualUMUC Physical Science NSCI101/103© 2012, eScience Labs LLCAll rights reservedwww.eciencelabs.com 888 375 5487Table of ContentsCustom Lab Manual for Physical Science NSCI 101/103Lab 1: Introduc on to ScienceLab 2: Types of ForcesLab 3: Newton’s LawsLab 4: Acids & BasesLab 5: Chemical ProcessesLab 6: LightLab 7: Radioac vity3Time and Addi onal Materials RequiredTime and Addi onal Materials Required for Each LabLab 1: Introduc on to Scienceo Time Required: 60 minuteso Addi onal Materials Needed: NoneLab 2: Types of Forceso Time Required: 60 minuteso Addi onal Materials Needed: NoneLab 3: Newton’s Lawso Time Required: 60 minuteso Addi onal Materials Needed: A deep dish, water, 2 chairs (for supports)Lab 4: Acids and Baseso Time: 60 min.o Materials needed: Tomato juice, dis lled water, milkLab 5: Chemical Processeso Time: 60 min.o Materials needed: noneLab 6: Lighto Time Required: 45 60 minuteso Addi onal Materials Needed: White paperLab 7: Radioac vityo Time Required: 45 60 minuteso Addi onal Materials Needed: None4Lab SafetyLab SafetyAlways follow the instruc ons in your laboratory manual and these general rules:eScience Labs, LLC designs every kit with safety as our top priority.Nonetheless, these are science kits and contain items which must behandled with care. Safety in the laboratory always comes first!Lab prepara onPlease thoroughly read the lab exercise before star ng!If you have any doubt as to what you are supposed to be doing and how to do it safely,please STOP and then:Double check the manual instruc ons.Check www.esciencelabs.com for updates and ps.Contact us for technical support by phone at 1 888 ESL Kits (1 888 375 5487) or byemail at Help@esciencelabs.com.Read and understand all labels on chemicals.If you have any ques ons or concerns, refer to the Material Safely Data Sheets(MSDS) available at www.esciencelabs.com. The MSDS lists the dangers, storagerequirements, exposure treatment and disposal instruc ons for each chemical.Consult your physician if you are pregnant, allergic to chemicals, or have other medicalcondi ons that may require addi onal protec ve measures.Proper lab a reRemove all loose clothing (jackets, sweatshirts, etc.) and always wear closed toe shoes.Long hair should be pulled back and secured and all jewelry (rings, watches, necklaces,earrings, bracelets, etc.), should be removed.Safety glasses or goggles should be worn at all mes. In addi on, wearing so contactlenses while conduc ng experiments is discouraged, as they can absorb poten allyharmful chemicals.5Lab SafetyWhen handling chemicals, always wear the protec ve goggles, gloves, and apronprovided.Performing the experimentDo not eat, drink, chew gum, apply cosme cs or smoke while conduc ng an experiment.Work in a well ven lated area and monitor experiments at all mes, unless instructedotherwise.When working with chemicals:Never return unused chemicals to their original container or place chemicals in anunmarked container.Always put lids back onto chemicals immediately a er use.Never ingest chemicals. If this occurs, seek immediate help.Call 911 or “Poison Control” 1 800 222 1222Never pipe e anything by mouth.Never leave a heat source una ended.If there is a fire, evacuate the room immediately and dial 911.Lab Clean up and DisposalIf a spill occurs, consult the MSDS to determine how to clean it up.Never pick up broken glassware with your hands. Use a broom and a dustpan and discard in a safe area.Do not use any part of the lab kit as a container for food.Safely dispose of chemicals. If there are any special requirements for disposal, it willbe noted in the lab manual.When finished, wash hands and lab equipment thoroughly with soap and water.Above all, USE COMMON SENSE!6Student PortalStudent Portal ContentIntroduc ono Safety Videoo Scien fic Method VideoNewtonian Mechanicso The Science of Sailing Videoo The Moving Mano Slam Dunk Scienceo The Science of Skateboardingo Projec le Mo ono Ladybug Revolu ono Energy Skate ParkChemistry and LightoAcid base reac onso Geometric Op csLog on to the Student Portal using theseeasy steps:Visit our website, www.esciencelabs.com,and click on the green bu on (says“Register or Login”) on the top right sideof the page. From here, you will be takento a login page. If you are registering yourkit code for the first me, click the “createan account” hyperlink. Locate the kitcode,located on a label on the inside of the kitbox lid. Enter this, along with other requested informa on into the online formto create your user account. Be sure tokeep track of your username and password as this is how you will enter the Student Portal for future visits. This establishes your account with the eScience Labs’Student Portal.Have fun!7Lab 1: Introduc on to ScienceLab 1: Introduc on to ScienceConcepts to explore:Scien fic Nota onThe Scien fic MethodSignificant DigitsObserva onsData Collec onHypothesisTablesVariablesGraphsControlsPercent ErrorData AnalysisScien fic ReasoningUnit ConversionsWri ng a Lab ReportWhat is science? You have likely taken several classes throughout your career as a student, and know that itis more than just chapters in a book. Science is a process. It uses evidence to understand the history of thenatural world and how it works. Scien fic knowledge is constantly evolving as we understand more about thenatural world. Science begins with observa ons that can be measured in some way, and o en concludes withobserva ons from analyzed data.Following the scien fic method helps to minimize bias when tes ng a theory. It helps scien sts collect andorganize informa on in a useful way so that pa erns and data can be analyzed in a meaningful way. As a scien st, you should use the scien fic method as you conduct the experiments throughout this manual.Figure 1: The process of the scien fic method11Lab 1: Introduc on to ScienceThe process of the scien fic method begins with an observa on. For example, suppose you observe a plant growing towards a window. This observa on could be the first step in designing an experiment. Rememberthat observa ons are used to begin the scien fic method, but they mayalso be used to help analyze data.Observa ons can be quan ta ve (measurable), or qualita ve(immeasurable; observa onal). Quan ta ve observa ons allow us to record findings as data, and leave li le room for subjec ve error. Qualita veobserva ons cannot be measured. They rely on sensory percep ons. Thenature of these observa ons makes them more subjec ve and suscep bleFigure 2: What a ects plant growth?to human error.Let’s review this with an example. Suppose you have a handful of pennies. You can make quan ta ve observaons that there are 15 pennies, and each is 1.9 cm in diameter. Both the quan ty, and the diameter, can be precisely measured. You can also make qualita ve observa ons that they are brown, shiny, or smooth. The color andtexture are not numerically measured, and may vary based on the individual’s percep on or background.Quan ta ve observa ons are generally preferred in sciencebecause they involve "hard" data. Because of this, many scien fic instruments, such as microscopes and scales, havebeen developed to alleviate the need for qualita ve observaIf plants grow quicker when nutrients are added,then the hypothesis is accepted and the nullhypothesis is rejected.ons. Rather than observing that an object is large, we cannow iden fy specific mass, shapes, structures, etc.There are s ll many situa ons, as you will encounter throughout this lab manual, in which qualita ve observaons provide useful data. No cing the color change of a leaf or the change in smell of a compound, for example,are important observa ons and can provide a great deal of prac cal informa on.Once an observa on has been made, the next step is to develop a hypothesis. A hypothesis is a statement describing what the scien st thinks will happen in the experiment. A hypothesis is a proposed explana on for anevent based on observa on(s). A null hypothesis is a testable statement that if proven true, means the hypothesis was incorrect. Both a hypothesis and a null hypothesis statement must be testable, but only one can be true.Hypotheses are typically wri en in an if/then format. For example:Hypothesis:If plants are grown in soil with added nutrients, then they will grow faster than plants grown withoutadded nutrients.12Lab 1: Introduc on to ScienceNull hypothesis:If plants are grown in soil with added nutrients, then they will grow at the same rate asIf plants grow quicker when nutrients are added,then the hypothesis is accepted and the nullhypothesis is rejected.plants grown in soil without nutrients.There are o en many ways to test a hypothesis. However, three rules must always be followed for results to be valid.The experiment must be replicable.Only test one variable at a me.Always include a control.Experiments must be replicable to create valid theories. In other words, anexperiment must provide precise results over mul ple trials Precise resultsare those which have very similar values (e.g., 85, 86, and 86.5) over mulple trials. By contrast, accurate results are those which demonstrate whatyou expected to happen (e.g., you expect the test results of three studentstests to be 80%, 67%, and 100%). The following example demonstrates thesignificance of experimental repeatability. Suppose you conduct an experiment and conclude that ice melts in 30 seconds when placed on a burner,but you do not record your procedure or definethe precise variables included. The conclusionthat you draw will not be recognized in the scienPrecise results may not hitthe bulls eye, but they allhit the same region.fic community because other scien sts cannotrepeat your experiment and find the same results. What if another scien sttries to repeat your ice experiment, but does not turn on the burner; or, uses a larger ice chunk. The results will not be the same, because the experiAccurate results all hit the ment was not repeated using the same procedure. This makes the resultsbulls eye on a target.invalid, and demonstrates why it is important for an experiment to be replicable.Variables are defined, measurable components of an experiment. Controlling variables in an experiment allows the scien st to quan fy changes that occur. This allows for focused results to be measured; and, for refined conclusions to be drawn. There are two types of variables, independent variablesand dependent variables.Independent variables are variables that scien sts select to change. For example, the me of day,amount of substrate, etc. Independent variables are used by scien sts to test hypotheses. There can13Lab 1: Introduc on to Scienceonly be one independent variable in each experiment. This is because if a change occurs, scien stsneed to be able to pinpoint the cause of the change. Independent variables are always placed on the xaxis of a chart or graph.Dependent variables are variables that scien sts observe in rela onship to the independent variable.Common examples of this are rate of reac on, color change, etc. Any changes observed in the dependent variable are caused by the changes in the independent variable. In other words, they depend onthe independent variable. There can be more than one dependent variable in an experiment. Dependent variables are placed on the y axis of a chart or graph.A control is a sample of data collected in an experiment that is not exposed to the independent variable. The control sample reflects the factors that could influence the results of the experiment, but donot reflect the planned changes that might result from manipula ng the independent variable. Controls must be iden fied to eliminate compounding changes that could influence results. O en, thehardest part of designing an experiment is determining how to isolate the independent variable andcontrol all other possible variables. Scien sts must be careful not to eliminate or create a factor thatcould skew the results. For this reason, taking notes to account for uniden fied variables is important.This might include factors such as temperature, humidity, me of day, or other environmental condions that may impact results.There are two types of controls, posi ve and nega ve. Nega ve controls are data samples in whichyou expect no change to occur. They help scien sts determine that the experimental results are due tothe independent variable, rather than an uniden fied or unaccounted variable. For example, supposeyou need to culture bacteria and want to include a nega ve control. You could create this by streakinga sterile loop across an agar plate. Sterile loops should not create any microbial growth; therefore, youexpect no change to occur on the agar plate. If no growth occurs, you can assume the equipment usedwas sterile. However, if microbial growth does occur, you must assume that the equipment was contaminated prior to the experiment and must redo the experiment with new materials.Alterna vely, posi ve controls are data samples in which you do expect a change. Let’s return to thegrowth example, but now you need to create a posi ve control. To do this, you now use a loop tostreak a plate with a sample that you know grows well on agar (such as E. coli). If the bacteria grow,you can assume that the bacteria sample and agar are both suitable for the experiment. However, ifthe bacteria do not grow, you must assume that the agar or bacteria has been compromised and youmust re do the experiment with new materials.14Lab 1: Introduc on to ScienceThe scien fic method also requires data collec on. This may reflect what occurred before, during, ora er an experiment. Collected results help reveal experimental results. Results should include all relevant observa ons, both quan ta ve and qualita ve.A er results are collected, they can be analyzed. Data analysis o en involves a variety of calcula ons,conversions, graphs, tables etc. The most common task a scien st faces is unit conversion. Units ofme are a common increment that must be converted. For example, suppose half of your data is measured in seconds, but the other half is measured in minutes. It will be di cult to understand the relaonship between the data if the units are not equivalent.When calcula ng a unit conversion, significant digits must be accounted for. Significant digits are thedigits in a number or answer that describe how precise the value actually is. Consider the followingrules:RuleAny non zero number (1 9) is always significantAny me a zero appears between significant numbers, the zero is significantZeros that are ending numbers a er a decimalpoint or zeros that are a er significant numbersbefore a decimal point are significantZeros that are used as placeholders are NOT significant digitsA zero at the end of a number with no decimalcan be a significant digitExample45 has two significant digits3.99 has three significant digits248678 has six significant digits4005 has four significant digits0.34000000009 has eleven significant digits45.00 has four significant digits15000.00 has seven significant digits62000000 has only two significant digits.0000000897 has only three significant digits50 cm exactly has two significant digits (notrounded)Addi on and subtrac on problems should result in an answer that has the same number of significantdecimal places as the least precise number in the calcula on. Mul plica on and division problemsshould keep the same total number of significant digits as the least precise number in the calcula on.For example:Addi on Problem: 12.689 + 5.2 = 17.889Mul plica on Problem: 28.8 x 54.76 = 1577.088round to 18round to 1580 (3 sig. digits)15Lab 1: Introduc on to ScienceScien fic nota on is another common method used to transform a number. Scien fic data is o en verylarge (e.g., the speed of light) or very small (e.g., the diameter of a cell). Scien fic nota on provides anabbreviated expression of a number, so that scien sts don’t get caught up coun ng a long series ofzeroes.There are three parts to scien fic nota on: the base, the coe cient and the exponent. Base 10 is almost always used and makes the nota on easy to translate. The coe cient is always a number between 1 and 10, and uses the significant digits of the original number. The exponent tells us whetherthe number is greater or less than 1, and can be used to “count” the number of digits the decimal mustbe moved to translate the number to regular nota on. A nega ve exponent tells you to move the decimal to the le , while a posi ve one tells you to move it to the right.For example, the number 5,600,000 can be wri en as 5.6 x 106. If you mul ply 5.6 by 10 six mes, youwill arrive at 5,600,000. Note the exponent, six, is posi ve because the number is larger than one. Alterna ve, the number 0.00045 must be wri en using a nega ve exponent. To write this number in scien fic nota on, determine the coe cient. Remember that the coe cient must be between 1 and 10.The significant digits are 4 and 5. Therefore, 4.5 is the coe cient. To determine the exponent, counthow many places you must move the decimal over to create the original number. Moving to the le ,we have 0.45, 0.045, 0.0045, and finally 0.00045. Since we move the decimal 4 places to the le , ourexponent is 4. Wri en in scien fic nota on, we have 4.5 x 10 4Although these calcula ons may feel laborious, a well calculated presenta on can transform data intoa format that scien sts can more easily understand and learn from. Some of the most common methods of data presenta on are:Table: A well organized summary of data collected. Tables should display any informa on relevant tothe hypothesis. Always include a clearly stated tle, labeled columns and rows, and measurementunits.VariableControl(without nutrients)Independent(with nutrients)16Table Example: Plant Growth With and Without Added NutrientsHeight Wk. 1 (mm)Height Wk. 2 (mm)Height Wk. 3 (mm)Height Wk. 4 (mm)3.43.63.73.53.74.14.04.6Lab 1: Introduc on to ScienceGraph: A visual representa on of the rela onship between the independent and dependent variable.They are typically created by using data from a table. Graphs are useful in iden fying trends and illustra ng findings. When construc ng a graph, it is important to use appropriate, consistent numericalintervals. Titles and axes labels should also reflect the data table informa on. There are several di erent types of graphs, and each type serves a di erent purpose. Examples include line graphs or bargraphs. Line graphs show the rela onship between variables using plo ed points that are connectedwith a line. There must be a direct rela onship and dependence between each point connected. Morethan one set of data can be presented on a line graph. By comparison, bar graphs: compare results thatare independent from each other, as opposed to a con nuous series.Height(mm)Figure 3: Plant growth, with and without nutrients, over meSpeed (kph)Figure 4: Top speed for Cars A, B, C, and D17Lab 1: Introduc on to ScienceA er compiling the data, scien sts analyze the data to determine if the experiment supports or refutes the hypothesis. If the hypothesis is supported, you may want to consider addi onal variablesthat should be examined. If your data does not provide clear results, you may want to consider running addi onal trials or revising the procedure to create a more precise outcome.One way to analyze data is to calculate percent error. Many experiments perform trials which calculate known value. When this happens, you can compare experimental results to known values and calculate percent error. Low percent error indicates that results are accurate, and high percent error indicates that results are inaccurate. The formula for percent error is:Percent Error = |(Experimental—Actual)| x 100%ActualNote that the brackets in the numerator indicate “absolute value”. This means that the number in theequa on is always posi ve.Suppose your experiment involves gravity. Your experimental results indicate that the speed of gravityis 10.1 m/s2, but the known value for gravity is 9.8 m/s2. We can calculate the percent error throughthe following steps:Percent Error =Percent Error =|(10.1 m/s2 9.8 m/s2)|(9.8 m/s2)|0.3 | x 100%(9.8 )Percent Error = 0.0306 x 100% = 3.1%x 100%(Note the units cancel each other out)(Remember the significant digits)The scien fic method gives us a great founda on to conduct scien fic reasoning. The more data andobserva ons we are able to make, the more we are able to accurately reason through the natural phenomena which occur in our daily lives. Scien fic reasoning does not always include a structured labreport, but it always helps society to think through di cult concepts and determine solu ons. For example, scien fic reasoning can be used to create a response to the changing global climate, developmedical solu ons to health concerns, or even learn about subatomic par cles and tendencies.Although the scien fic method and scien fic reasoning can guide society through cri cal or abstractthinking, the scien fic industry typically promotes lab reports as a universal method of data analysisand presenta on. In general terms, a lab report is a scien fic paper describing the premise of an experiment, the procedures taken, and the results of the study. They provide a wri en record of what18Lab 1: Introduc on to Sciencetook place to help others learn and expedite future experimental processes. Though most lab reports go unpublished, it is important towrite a report that accurately characterizes the experiment performed.Figure 5: Lab reports are an importantpart of science, providing a way toreport conclusions and ideas.Part of the Lab ReportTitleAbstractPurposeA short statement summarizing the topicA brief summary of the methods, results and conclusions. It should not exceed 200 wordsand should be the last part wri en.An overview of why the experiment was conducted. It should include:Introduc onBackground Provide an overview of what is already known and what ques ons remain unresolved. Be sure the reader is given enough informa on to know why andhow the experiment was performed.Objec ve Explain the purpose of the experiment (i.e. "I want to determine if takingbaby aspirin every day prevents second heart a acks.")Hypothesis This is your "guess" as to what will happen when you do the experiment.Materials and MethodsResultsA detailed descrip on of what was used to conduct the experiment, what was actuallydone (step by step) and how it was done. The descrip on should be exact enough thatsomeone reading the report can replicate the experiment.Data and observa ons obtained during the experiment. This sec on should be clear andconcise. Tables and graphs are o en appropriate in this sec on. Interpreta ons should notbe included here.Data interpreta ons and experimental conclusions.DiscussionDiscuss the meaning of your findings. Look for common themes, rela onships andpoints that perhaps generate more ques ons.When appropriate, discuss outside factors (i.e. temperature, me of day, etc.) thatmay have played a role in the experiment.Iden fy what could be done to control for these factors in future experiments.ConclusionA short, concise summary that states what has been learned.ReferencesAny ar cles, books, magazines, interviews, newspapers, etc. that were used to supportyour background, experimental protocols, discussions and conclusions.19Lab 1: Introduc on to ScienceExercise 1: Data Interpreta onDissolved oxygen is oxygen that is trapped in a fluid, such as water. Since virtually every living organism requires oxygen to survive, it is a necessary component of water systems such as streams, lakesand rivers in order to support aqua c life. The dissolved oxygen is measured in units of ppm—or partsper million. Examine the data in Table 2 showing the amount of dissolved oxygen present and thenumber of fish observed in the body of water the sample was taken from; finally, answer the quesons below.Table 2: Water Quality vs. Fish Popula onDissolved Oxygen(ppm)024681012141618Number of FishObserved01310121315101213Ques ons1. What pa erns do you observe based on the informa on in Table 2?2. Develop a hypothesis rela ng to the amount of dissolved oxygen measured in the water sampleand the number of fish observed in the body of water.3. What would your experimental approach be to test this hypothesis?4. What would be the independent and dependent…