Data in an experiment is comprised of certain and uncertain measurements. The digits in this data are called significant figures. This implies that all digits in a number are important; however, this is not true. Zeros that are used as placeholders after the decimal point are not significant. For example 0.0032 only has two significant figures, yet trailing zeros to the right of a decimal point are significant. So, the digit 94.00 has four significant figures. Furthermore, trailing zeroes of a whole number are not significant. So, the number 380 only has two significant figures. However, according to the Silberberg Chemistry textbook, trailing zeroes do count as significant figures. This is one instance where the course policy differs from that of the book. Nevertheless, course policy takes precedence over the textbook. All other numbers in all other circumstances are significant. When recording a measurement it is important to remember that every measurement is a comparison or estimate to a standard. Therefore, the measurement will always possess some type of random error. …show more content…
However, the objective of taking and recording measurements is to be as precise as possible. If recording a measurement from a digital instrument, record all the data given by the instrument. If using an analog instrument record all given measurements and estimate one more digit. The last digit of a measurement, whether given by an analog or digital instrument, is always considered the least precise. The more digits a measurement possesses, the more precise it is. However, this does not mean it is acceptable to exaggerate data,especially when performing a calculation. When performing an operation, the original data is used to determine how many significant figures there must be in the final answer. When adding or subtracting, round the final answer to the same decimal place as the least precise (shortest) piece of given data. If multiplying or dividing, round the final answer to the same amount of figures as the least precise piece of data. If both addition/subtraction and multiplication/ division are taking place in the same problem, follow the rules for multiplication and division. Assess and take note of how many significant figures would be used if it was a final answer, and use this as a restriction for the final answer of the problem. Never round in the middle of a problem. When performing a calculation, some given data, such as counted numbers or exact measurements (i.e. 1in=2.54cm); therefore, they do not have any say in significant digit restrictions. Rounding off is used in most calculations to acquire the correct number of significant figures or decimal places. If the digit being eliminated is greater than or equal to five, the prior term is increased by one. If the digit removed is less than five, the previous term is rounded down. For example, 373 g to significant figures would be rounded to 370g. However, 378g would be rounded to 380g. Often when rounding, it is difficult to get a number to be both accurate and within a specified number of significant figures.
For example, 377,000g cannot be rounded to two significant figures and still be accurate. When this occurs, scientific notation is helpful.Scientific notation is the way that scientists easily handle very large numbers or very small numbers. It is comprised of two parts: the coefficient and the exponent. The coefficient is always rounded to the proper number of significant digits. While the exponent (always to a power of ten in Chemistry) is inserted to make sure that the exact placement of the decimal point for the accurate full number is known. Therefore, 377,000 to two significant figures would be 3.8x10^5g. The standard way of writing a number in scientific notation is always to have only one digit to the left of the decimal. This one digit cannot be
zero. Significant figures is very important to chemists and other scientists alike are well aware of the importance of determining the most precise data that can be achieved in a measurement. The concept of significant figures is connected to an array of many concepts in Chemistry such as dimensional analysis, molar chemistry, and stoichiometry.
In addition, the data points were quite far apart. Having more intermediate data points would have enabled the scientists to more accurately model the continuous nature of the data with a discontinuous series of points.
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
...e been beneficial to the experiment. An error may have occurred due to the fact that measurements were taken by different individuals, so the calculations could have been inconsistent.
Possible sources of error in this experiment include the inaccuracy of measurements, as correct measurements are vital for the experiment.
I made a chart to record how my thermometer measured freezing and boiling water, and proceeded to find the average. I took the average of each, and used them to find the average inaccuracy of the thermometer. I found that the average inaccuracy of the thermometer for freezing water was of by 0.7°C or -0.7°C. The average inaccuracy of the thermometer for boiling water I recorded as off by 1°C or -1°C.
how much there is, and numbers tell you how many there are. This is cause for
In order for a set of data to be accurate, there needs to be another set of data from prior researchers that was concluded to be the only correct rate at which a birthday candle burns. Also, the data from this experiment cannot be identified as being precise, because if this experiment were to be repeated, due to the experimental error, the results would not be exact from the first time the experiment was performed. The first most important step of the procedure for data collection is the time that was recorded after lighting the candle. The time was important, because time was a factor in determining the answer to the experimental question, which was the rate at which the candle burns. Recording the time accurately is significant to the final results, because if the time was not recorded in this experiment, it would be impossible to answer the experimental question. The second step that contributed to data collection was the massing of the candle. If it wasn’t done properly, the rate of the burning candle would have been slightly off. These two steps were the most important in gathering the data, because the time and the mass were both needed in order to calculate the
0.000 7 63 106 55 74.7 1.245 9 70 135 90 98.3 1.638 11 85 135 70 96.8 1.613 [ IMAGE ] [ IMAGE ] Conclusion = = = =
There can be percentage errors and uncertainties or heat loss in surrounding while executing the experiment.
Unlike Present Day, where most scientific groups and people use the standard unit of measurement; the metric system, there used to be a time when a variety of units of measurement were frequently used throughout the world, some units were also measured using the human body. For example length could be measured in numerous ways such as feet, hands, cubits, palms, rods, furlongs and many more. This creation of multiple varying units created an absence in common measurement standards, leading to a lot of misunderstanding and a significant drop of efficiency in the trade between countries. This havoc remained persistent until the eighteenth century when those countries had learnt that “United We Stand; Divided We Fall”-Aesop.
Chapter two of The Universe and the Teacup deals with exponential numbers. More precisely, it deals with the difficulty humans have in processing very large and very small numbers. The term the book uses to describe this difficulty is "number numbness."
General uncertainty – the quality of the readings of most instruments decreases over time due to any number of environmental and internal factors, as frequent calibration is necessary. When several consecutive incorrect readings are taken for a liquid of known specific density, it is clear that the hydrometer is out of
...gle with our naked eye). This error can occur in a lab when he observer’s eye is not squarely aligned with the instrument at hand being used. We may have read too high or too low of a value when using the protractor to determine an angle and our data may have been altered by a very small degree of numbers.
accurate and reliable [6, 8, 9]. In addition, it has an added advantage if varying
... point was subjective; however it would have been a systematic error because I consistently judged the end point of my experiment. To eliminate this inaccuracy I should have used a colorimeter to judge the end point of my experiment.