The Work of Scientists Table of Contents MeasurementA
The Work of Scientists Table of Contents Measurement–A Common Language Mathematics and Science Graphs in Science Safety in the Science Laboratory
The Work of Scientists - Measurement–A Common Language A Standard Measurement System Using SI as the standard system of measurement allows scientists to compare data and communicate with each other about their results. SI units are based on multiples of 10.
The Work of Scientists - Measurement–A Common Language Length The basic unit of length in the SI system is the meter (m).
The Work of Scientists - Measurement–A Common Language Mass The basic unit of mass in the SI system is the kilogram (kg).
The Work of Scientists - Measurement–A Common Language Volume is the amount of space an object takes up.
The Work of Scientists - Measurement–A Common Language Density Because density is actually made up of two other measurements–mass and volume–an object’s density is expressed as a combination of two units.
The Work of Scientists - Measurement–A Common Language Calculating Density Suppose that a metal object has a mass of 57 g and a volume of 21 cm 3. Calculate its density. Read and Understand What information are you given? Mass of metal object = 57 g Volume of metal object = 21 cm 3
The Work of Scientists - Measurement–A Common Language Calculating Density Suppose that a metal object has a mass of 57 g and a volume of 21 cm 3. Calculate its density. Plan and Solve What quantity are you trying to calculate? The density of the metal object = __ What formula contains the given quantities and the unknown quantity? Density = Mass/Volume Perform the calculation. Density = Mass/Volume = 57 g/21 cm 3 = 2. 7 g/cm 3
The Work of Scientists - Measurement–A Common Language Calculating Density Suppose that a metal object has a mass of 57 g and a volume of 21 cm 3. Calculate its density. Look Back and Check Does your answer make sense? The answer tells you that the metal object has a density of 2. 7 g/cm 3. The answer makes sense because it is the same as the density of a known metal–aluminum.
The Work of Scientists - Measurement–A Common Language Calculating Density Practice Problem What is the density of a wood block with a volume of 125 cm 3 and a mass of 57 g? 0. 46 g/cm 3
The Work of Scientists - Measurement–A Common Language Calculating Density Practice Problem What is the density of a liquid with a mass of 45 g and a volume of 48 m. L? 0. 94 g/m. L
The Work of Scientists - Measurement–A Common Language Time The second (s) is the SI unit to measure time.
The Work of Scientists - Measurement–A Common Language Temperature In addition to the Celsius scale, scientists sometime use another temperature scale, called the Kelvin scale. The kelvin (K) is the official SI unit for temperature.
The Work of Scientists - Measurement–A Common Language Converting Between Units Using the appropriate conversion factor, you can easily convert one unit of measurement to another. This example shows how to convert 1. 5 kilometers to meters.
The Work of Scientists - Measurement–A Common Language Comparing and Contrasting As you read, compare and contrast different types of measurement by completing a table like the one below. Characteristic Definition SI Unit Measuring Tool Length Distance from one point to another Mass Amount of matter Time Temperature Passing of events Hotness or coldness Meter (m) Gram (g) Second (s) Degrees of Celsius or Kelvin Metric ruler Balance Watch or clock Thermometer
The Work of Scientists - Measurement–A Common Language More on Measurement Click the PHSchool. com button for an activity about measurement.
The Work of Scientists End of Section: Measurement– A Common Language
The Work of Scientists - Mathematics and Science Area The area of a surface is the amount of space it covers. To find the area, multiply its length by its width. Remember to multiply the units as well. Area = Length x Width Suppose an area measures 12. 0 m by 11. 0 m. Area = 12. 0 m x 11. 0 m = 132 m 2 Practice Problem Calculate the area of room 4. 0 m long and 3. 0 m wide. 4. 0 m x 3. 0 m = 12 m 2
The Work of Scientists - Mathematics and Science Area The area of a surface is the amount of space it covers. To find the area, multiply its length by its width. Remember to multiply the units as well. Area = Length x Width Suppose an area measures 12. 0 m by 11. 0 m. Area = 12. 0 m x 11. 0 m = 132 m 2 Practice Problem Calculate the area of a ticket stub 5. 1 mm long and 2. 62 mm wide. 5. 1 mm x 2. 62 mm = 13. 4 mm 2 (13, to the correct significant figure)
The Work of Scientists - Mathematics and Science Accuracy and Precision In order to hit the bull’s-eye consistently, you need both accuracy and precision.
The Work of Scientists - Mathematics and Science Significant Figures The significant figures in a measurement include all of the digits that have been measured exactly, plus one digit whose value has been estimated.
The Work of Scientists - Mathematics and Science Significant Figures When you multiply measurements, your answer can only have the same number of significant figures as the measurement with the fewest significant figures.
The Work of Scientists - Mathematics and Science Percent Error You calculate the density of an object to be 9. 37 g/cm 3. The density of the object is actually 8. 92 g/cm 3. Calculate your percent error. Read and Understand What information are you given? Experimental value = 9. 37 g/cm 3 True value = 8. 92 g/cm 3
The Work of Scientists - Mathematics and Science Percent Error You calculate the density of an object to be 9. 37 g/cm 3. The density of the object is actually 8. 92 g/cm 3. Calculate your percent error. Plan and Solve What quantity are you trying to calculate? Percent error = __ What formula contains the given quantities and the unknown quantity?
The Work of Scientists - Mathematics and Science Percent Error You calculate the density of an object to be 9. 37 g/cm 3. The density of the object is actually 8. 92 g/cm 3. Calculate your percent error. Plan and Solve Perform the calculation. Percent Error = 5. 04%
The Work of Scientists - Mathematics and Science Percent Error You calculate the density of an object to be 9. 37 g/cm 3. The density of the object is actually 8. 92 g/cm 3. Calculate your percent error. Look Back and Check The answer tells you that your percent error is about 5%. This answer makes sense because the experimental value and the true value were close to each other.
The Work of Scientists - Mathematics and Science Percent Error Tanya measured the mass of an object to be 187 g. Sam measured the object’s mass to be 145 g. The object’s actual mass was 170 g. What is Tanya’s percent error? 10. 0%
The Work of Scientists - Mathematics and Science Percent Error Tanya measured the mass of an object to be 187 g. Sam measured the object’s mass to be 145 g. The object’s actual mass was 170 g. What is Sam’s percent error? 14. 7%
The Work of Scientists - Mathematics and Science Mean, Median, and Mode The mean is the numerical average of the numbers in a list.
The Work of Scientists - Mathematics and Science Mean, Median, and Mode If an ordered list has an odd number of entries, the median is the middle number in a set of data. If a list has an even number of entries, the median is the sum of the two middle numbers divided by two.
The Work of Scientists - Mathematics and Science Mean, Median, and Mode The mode is the number that appears most often in a list of numbers.
The Work of Scientists - Mathematics and Science Asking Questions Before you read, preview the red headings. In a graphic organizer like the one below, ask a what, how, or why question for each heading. As you read, write the answers to your questions. Questions Answers What does estimation have to do with science? Scientists use estimation when they cannot obtain exact measurements. What are accuracy and precision? Accuracy refers to how close a measurement is to the true or accepted value, and precision refers to how close a group of measurements are to each other. What are significant figures? The term significant figures refers to the digits in a measurement. What is percent error? Percent error is a calculation used to determine how accurate an experimental value really is. What are mean, median, and mode? They are ways to calculate an “average. ”
The Work of Scientists - Mathematics and Science Links on Math and Science Click the Sci. Links button for links on math and science.
The Work of Scientists End of Section: Mathematics and Science
The Work of Scientists - Graphs in Science The Importance of Graphs Line graphs are used to display data to show one variable changes in response to another variable. In this experiment, the responding variable is the time it takes for the water to boil. The manipulated variable is the volume of water in the pot.
The Work of Scientists - Graphs in Science Plotting a Line Graph
The Work of Scientists - Graphs in Science Plotting a Line Graph Activity Click the Active Art button to open a browser window and access Active Art about plotting a line graph.
The Work of Scientists - Graphs in Science Why Draw a Line of Best Fit? A line of best fit emphasizes the overall trend shown by all the data taken as a whole.
The Work of Scientists - Graphs in Science Slope The slope of a graph line tells you how much y changes for every change in x.
The Work of Scientists - Graphs in Science Car Travel The graph shows the distance a car travels in a one-hour period. Use the graph to answer the questions that follow.
The Work of Scientists - Graphs in Science Car Travel Reading Graphs: What variable is plotted on the horizontal axis? What variable is plotted on the vertical axis? Time (min), the manipulated variable, is plotted on the horizontal axis. Distance (km), the responding variable, is plotted on the vertical axis.
The Work of Scientists - Graphs in Science Car Travel Interpreting Data: How far does the car travel in the first 10 minutes? In 40 minutes? The car travels 10 km in 10 minutes and 40 km in 40 minutes.
The Work of Scientists - Graphs in Science Car Travel Predicting: Use the graph to predict how far the car would travel in 120 minutes. Assume the car continues to travel at the same speed. The car is traveling 1 km per minute. It would travel 120 km in 120 minutes.
The Work of Scientists - Graphs in Science Car Travel Calculating: Calculate the slope of the graph. What information does the slope provide about the speed of Car 2? The slope is 1 km/min. The slope provides information about the car’s average speed.
The Work of Scientists - Graphs in Science Car Travel Drawing Conclusions: Compare the graphs for Car 1 and Car 2. What is the relationship between the steepness of the graph lines and the speed of the cars? The slope of the graph for Car 1 is 0. 5 km/min. Because the distance and time values are marked the same on the two graphs, a steeper line represents a greater speed. Car 2 is traveling twice as fast as Car 1.
The Work of Scientists - Graphs in Science Using Graphs to Identify Trends Line graphs are powerful tools in science because they allow you to identify trends and make predictions.
The Work of Scientists - Graphs in Science Building Vocabulary A definition states the meaning of a word or phrase by telling about its most important feature or function. After you read the section, reread the paragraphs that contain definitions of Key Terms. Use all the information you have learned to write a definition of each Key Term in your own words. Key Terms: graph coordinate slope nonlinear graph horizontal data point axis vertical axis line of best fit origin linear graph Examples: The A graph coordinate slope is of a picture aisgraph a point ofline data onisathat how graph reveals steep thatthe ispatterns determined line is. or trends. by a pair of numbers. A nonlinear graph is a graph on which the data points The A horizontal point onstraight axis a graph is the is graph whereline an imaginary that runs from line dodata not fall on a line. left tothe from right. horizontal axis would meet an imaginary line from the vertical The vertical axis. is the graph line that runs up and The line of best fit on a graph is a smooth line down. between points that reflects general of the The origin of a graph is the point where pattern the horizontal points. and vertical axes meet. A linear graph is a straight-line graph.
The Work of Scientists End of Section: Graphs in Science
The Work of Scientists - Safety in the Science Laboratory Safety in the Lab These safety symbols remind you to work carefully when performing labs in this textbook series. Make sure you are familiar with each safety symbol and what it means.
The Work of Scientists - Safety in the Science Laboratory In Case of an Accident When any accident occurs, no matter how minor, notify your teacher immediately. Then listen to your teacher’s directions and carry them out quickly.
The Work of Scientists - Safety in the Science Laboratory Outlining As you read, make an outline about science safety that you can use for review. Use the red headings for the main topics and the blue headings for supporting ideas. Safety in the Science Laboratory I. Safety in the Lab A. Preparing for the Lab B. Performing the Lab C. End-of-Lab Procedures II. Safety in the Field III. In Case of an Accident
The Work of Scientists - Safety in the Science Laboratory Links on Laboratory Safety Click the Sci. Links button for links on laboratory safety.
The Work of Scientists End of Section: Safety in the Science Laboratory
The Work of Scientists Graphic Organizer Average can be a Mean Median Mode is is is The numerical average The middle number The number that appears most often in a list of numbers
The Work of Scientists End of Section: Graphic Organizer
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