Why Do I Have This Error "[e::bgzf Read] Read Block Operation Failed With Error -1"

Numbers presented to students in geoscience always have some error associated with them. Anytime data is presented in course, not only in an instrumentation course, information technology is important they empathize the errors associated with that information. Many times these errors are a issue of measurement errors. Even numerical values obtained from models accept errors that are, in part, associated with measurement errors, since observation data is used to initialize the model. Measurement errors by and large fall into ii categories: random or systematic errors. All the same fifty-fifty if we know about the types of error we even so demand to know why those errors be. We can break these into two bones categories: Musical instrument errors and Operator errors.

Random Errors

Random errors are ones that are easier to deal with because they cause the measurements to fluctuate around the truthful value. If we are trying to measure out some parameter X, greater random errors cause a greater dispersion of values, but the mean of Ten still represents the true value for that instrument.

Systematic Errors

A systematic error tin exist more catchy to track downward and is often unknown. This error is oftentimes called a bias in the measurement. In chemistry a teacher tells the student to read the volume of liquid in a graduated cylinder past looking at the meniscus. A student may make an error past reading the volume by looking at the liquid level about the edge of the glass. Thus this student will e'er be off past a sure amount for every reading he makes. This is a systematic error. Instruments often have both systematic and random errors.

What Causes Measurement Errors?

Now that we know the types of measurement errors that tin occur, what factors lead to errors when we take measurements? We tin separate this category into 2 bones categories: instrument and operator errors. Human errors are not ever blunders notwithstanding since some mistakes are a result of inexperience in trying to brand a particular measurement or trying to investigate a particular problem.

Instrument Errors

When you purchase an instrument (if it is of any existent value) it comes with a long list of specs that gives a user an idea of the possible errors associated with that instrument. In labs as a faculty you lot may be using equipment that is non new, so you should help students be aware of the errors associated with the instrument. If the company that made the musical instrument still exists you tin can contact them to find out this information as well. Looking at these advisedly tin aid avoid poor measurements and poor usage of the instrument. Students when they hand in labs can calculate and represent errors associated with their data which is important for every scientist or future scientist. Some basic data that usually comes with an instrument is:

• accurateness - this is simply a measurement of how accurate is a measurement likely to be when making that measurement within the range of the instrument. For instance a mercury thermometer that is only marked off in tenth'south of a degree can really only exist measured to that degree of accuracy.
• range - instruments are mostly designed to mensurate values but within a certain range. This is usually a result of the physical properties of the instruments, such as instrument mass or the material used to brand the musical instrument. For case a cup anemometer that measures wind speed has a maximum rate that is tin spin and thus puts a limit on the maximum wind speed information technology can mensurate.
• response time - if an instrument is making measurements in irresolute conditions (which is pretty much the normal state of affairs on Earth) every instrument will accept time to detect that change. This once again is often associated with the concrete properties of the instrument. For example a mercury thermometer taken from room temperature and put into boiling water will take some time before it gets to 100 ^oC. Reading the thermometer as well early on volition give an inaccurate observation of the temperature of humid water.
• sensitivity - many instruments are have a limited sensitivity when detecting changes in the parameter being measured. For instance some cup anemometers, because of their mass cannot observe pocket-sized air current speeds. The problem gets the worse as the anemometer gets heavier.

Scale

Other instrument errors include calibration errors. All instruments need to be calibrated. Instruments are calibrated according to theory, standards and other instruments that as well have errors. Scale ideally should be performed against an musical instrument that is very accurate, but this can be costly, so it does non always happen.

Instruments Getting Old

All instruments have a finite lifetime, even when calibrated frequently. In class you may have an opportunity to show students the difference in measurements between an older and new instrument. Electronic instruments drift over time and devices that depend on moving parts ofttimes experience hysteresis. Hysteresis tin be a complex concept for kids but it is easily demonstrated by making an illustration to Slinkys or bed springs. You lot tin can too show the students a new deck of cards vs. an older deck of cards. You can shuffle the new cards a couple of times and the cards will quite obviously look new and flat. However, the old cards which take been shuffled and held in peoples hands many times, develop a curve to them, indicate the structural integrity of the cardboard has changed from its original form.

Operator Errors

These errors more often than not atomic number 82 to systematic errors and sometimes cannot be traced and frequently can create quite large errors. Through experimentation and observation scientists leard more all the time how to minimize the human factors that cause error. Operator errors are not only just reading a dial or display wrong (although that happens) simply can exist much more complicated. Every bit kinesthesia it is important to keep these in mind and so that in a lab or field situation students can obtain meaningful data. Making students aware of operator errors is definitely more of a preparatory lesson. Permit's explore some of these topics.

Measurement Location Errors

Data frequently has errors considering the instrument making the measurements was not placed in an optimal location for making this measurement. A good instance of this, is over again associated with measurements of temperature. Whatsoever temperature measurement will be in accurate if it is directly exposed to the sunday or is non properly ventilated. In addition, a temperature device identify too close to a building will likewise be erroneous because it receives heat from the edifice through conduction and radiations.

Ceremoniousness

A scientist must e'er ask himself/herself questions like: What is being measured? How oft does it need to exist measured? How accurate do I need to be? What conditions am I going to make the measurements in? Knowing the answer to these questions tin can help the scientist pick the appropriate instrument for the situation. An case of this is errors that used to be quite common in trying to measure temperature from an shipping. Thermometers that were unprotected got wet when flying through clouds thus making the temperature data useless. The device that was used was non appropriate for that experiment, where as it might accept been fine for many other situations. Some other instance would exist getting an electronic temperature device that can study temperature measurements ever 5 seconds when one actually just is trying to record the daily maximum and minimum temperature. This is a instance where the instrument was superfluous (and probably too expensive) for the type of measurement that needed to exist made.

Appropriateness can also chronicle to the spatial and temporal frequency in which measurements are made. Students may await at the global and average temperature and take it for truth, because nosotros have good temperature measurement devices. They may not be aware that the global average may exist fabricated with the same density of measurements in sparsely populated areas and poorer nations. Sampling issues can be a big source of error and if you are educational activity a statistics form yous may want to delve into this more than deeply. Providing your instruments are good the more data the better. Studying events that happen infrequently or unpredictably tin can also affect the certainty of your results. Although understanding what you are trying to measure tin help y'all collect no more than data than is necessary. For example sea surface temperatures in the eye of the ocean change very slowly, on the order of two weeks. It is therefore unnecessary to record temperature changes every half an hour or an hour.

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Source: https://serc.carleton.edu/quantskills/teaching_methods/und_uncertainty/measure_error.html

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