Every person who works in a certain field of activity is faced with measuring instruments. With their help, you can measure certain indicators and measure different objects.
You can buy such devices here, where they are available in a huge assortment. The accuracy of the result that you get in the end depends on the quality of the measuring device.
Determination of the scale division value
A certain value, which is called the price of division of the scale, is calculated according to certain rules.
Here are the main points to keep in mind:
- at the very beginning, you need to take those scale values that are located in the neighborhood;
- then it is necessary to calculate their difference;
- after that, count the number of intermediate divisions that are located between the same values;
- at the very end, the resulting difference is divided by the number of intermediate divisions.
These are the main steps that will help you determine the scale divisions. If you did it right, you can get the most accurate result.
Such devices have advantages that distinguish them favorably against the background of other options. The measuring devices are stable, capable of serving as long as possible, and show the result with the highest accuracy.
Professionals who work in different fields of activity often use multifunctional devices. With the help of such equipment, it is possible to measure simultaneously according to different indicators.
Modern measuring devices allow storing data in memory and sorting them into archives. If in the future you need to return to past information, then you will extract it and carefully review it.
Gauges have other benefits as well. For example, one device replaces several models at once.
It will be convenient for you to use such equipment, because it is very easy to carry it from place to place. You will have free hands, so you won't drop or break anything.
The main types of measuring equipment
You can use a rangefinder to measure different distances. It is a laser tool that accurately determines the depth of the well and the length of the load-bearing wall.
To get the most accurate leveling result, you need to purchase an optical level. This device is capable of solving many tasks and problems.
You can use the laser plane builder to build lines, apply markings or project different planes. Such a tool is indispensable during repairs or performing complex construction work.
Physical quantities. Measurement of physical quantities. We watch the accuracy and error of measurements in the video:
Believe it or not, the height of the tree was measured with a very long measuring tape; however, there are much simpler methods for determining the height of trees. While these methods do not always measure heights to the nearest centimeter (or inch), they are quite reliable and can measure any tall object, such as telegraph poles, buildings, and even a magic tree grown from a seed of bean: measurable any object as long as its top is visible.
Steps
Using a sheet of paper
- The section "Using a clinometer or theodolite" contains all the mathematical calculations and explanations, but they are not necessary to find the height of a tree using this method.
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Fold the piece of paper diagonally to form a triangle. If the sheet is not square, but rectangular, you need to make a square out of it. Fold a piece of paper along the corner, aligning two adjacent edges to form a triangle, and then cut off the excess edge protruding from under it. As a result, you will get the required triangle.
- The triangle will have one 90-degree angle and two 45-degree acute angles.
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Bring the triangle to one eye. Hold the sheet upright with the 90º right angle at the bottom and away from you. One of the short sides (legs) should be horizontal (parallel to the ground), the other - vertically (from bottom to top). Position the triangle so that with your eyes up, you can look along its long side.
- The long side of a right triangle along which your gaze is directed is called the hypotenuse.
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Move away from the tree until you see that its tip coincides with the apex of the triangle (its upper acute corner). Close one eye, looking with the other along the long side of the triangle, until the top of a tree appears above it. Make sure that your gaze, directed along the long side of the triangle, falls to the very top of the tree.
Mark an appropriate spot on the ground and measure the distance from it to the base of the tree. This will be almost full height of the tree. Your height should be added to the resulting value, since you were looking at the tree not from the ground itself, but from the height of your eyes. You have now found the relatively accurate height of the tree!
- The principle on which this method is based is detailed below in the "Using a Clinometer or Theodolite" section. This method does not require any calculations, since it uses the simple fact that the tangent of an angle of 45º degrees (these are the acute angles in our paper triangle) is 1. Thus, we can write the following equality: (tree height) / ( distance from the tree) = 1. Multiplying both sides of the equality by (distance from the tree), we get: height of the tree = distance from the tree.
This method allows you to find the height of the tree without resorting to mathematical calculations. All you need is a sheet of paper and a measuring tape. No computation required; however, if you want to know how this method works, you need a little familiarity with the basics of trigonometry.
Using a pencil (assistant required)
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This method can be used as an alternative to the previous one (shadow comparison). Although this method is less accurate, it can be used when it is not possible to find the height of the tree by comparing the length of the shadows, such as on an overcast day. Plus, if you have a tape measure, you can do without the math. Otherwise, if you can't find a roulette wheel, some simple calculations will be required.
Stand far enough from the tree so that you can see the entire tree, from base to top, without tilting or raising your head. For more accurate measurements, your feet should be level with the base of the tree, no higher or lower than it. Stand so that nothing is blocking or blocking the tree from you.
Take a pencil in your hand and pull it out in front of you. Instead of a pencil, you can use another small, straight object, such as a stick or ruler. With the pencil in your hand, straighten it so that the pencil is directly in front of you (between you and the tree).
Close one eye and wiggle the pencil to align the top of the eye with the top of the tree. In this case, it is better to hold the pencil with the sharpened end up. You want the top edge of the pencil to block the top of the tree from you as you look at the tree “through” the pencil.
Move your thumb along the pencil, making sure that the tip of your finger is aligned with the base of the tree. Holding the pencil so that its top end is aligned with the top of the tree (see step 3), move your thumb along the pencil to where you can see the base of the tree coming out of the ground (as before, while looking through the pencil with one eye on a tree). The pencil now "covers" the full height of the tree, from its base to the top.
Turn your hand so that the pencil is horizontal (along the ground). While doing this, keep your hand outstretched in front of you and make sure your thumb is still pointing to the base of the tree.
Ask your assistant to stand so that you can see him or her “on” the tip of the pencil. That is, your friend should stand in such a way that his feet "line up" with the top of the pencil. In this case, the assistant should be located at the same distance from you as the tree, no closer and no further. You and your assistant will be at some distance from each other (depending on the height of the tree), so you can communicate with him through gestures (using your second hand, which does not have a pencil), showing him where to move (further or closer, to the right or to the left ).
If you have a tape measure with you, measure the distance between your helper and the tree. Ask a friend to stay put, or mark the spot with a branch or pebble. Then measure with a tape measure the distance from this point to the base of the tree. This distance will be equal to the height of the tree.
If you don't have a tape measure handy, mark the height of your helper and the height of the tree on a pencil. Make a scratch or other mark on the pencil where your thumb was, thereby fixing the height of the tree from your vantage point. Then, just as with the tree, move the pencil so that it partially obscures your assistant, aligning the top of the pencil with the assistant's head and the thumb on the pencil with his feet. Mark the position of your thumb on the pencil again.
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Calculate the height of the tree by finding a measuring tape. To do this, you will need to measure the distance between the tip of the pencil and the marks made on it, as well as the height of your assistant; this can be done at home without going back to the tree. Scale the pencil lines according to the height of your helper. For example, if your friend's height mark is 5 centimeters (2 inches) from the tip of the pencil, and the tree's height mark is 17.5 centimeters (7 inches), then the tree is 3.5 times taller than your helper. because 17.5cm / 5cm = 3.5 (7 inches / 2 inches = 3.5). Let's say your friend is 180 centimeters (6 feet) tall, then the tree is 180 cm x 3.5 = 630 cm (6 x 3.5 = 21 feet).
- Note: if you have a measuring tape with you when you are near a tree, there is no need to make any calculations. Read the above step "if you have a tape measure with you" carefully.
Using a clinometer or theodolite
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This method provides more accurate results. Although the above methods are quite reliable, with a little more detailed calculations and special tools, you can get more accurate results. This is not as difficult as it seems at first glance: you only need a calculator with the function of calculating the tangent, as well as a simple plastic protractor, a straw and a thread, with which you can make a clinometer yourself. A clinometer, or inclinometer, allows you to measure the slope of objects, and in our case, the angle between you and the top of the tree. For this purpose, a more complex and accurate instrument is used, called theodolite, which includes a telescope or laser.
- In the Using a Sheet of Paper method, a paper triangle acts as a clinometer. This method, in addition to being more accurate, allows you to determine the height of a tree from any distance, instead of approaching or moving away from the tree, seeking to align the sheet of paper with the tree.
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Measure the distance to the observation point. Stand with your back to the tree and move away from it to a place that is level with its base, from where the top of the tree is clearly visible. At the same time, walk along a straight line, measuring the distance traveled from the tree with a tape measure. The distance from the tree can be arbitrary, but for this method it is best if it is 1-1.5 times the height of the tree.
Now you know the height of the tree. Since the clinometer or theodolite was not on the ground, but at eye level, you must add your height to the previously calculated value to find the full height of the tree. For more accurate results, you can measure the distance from your feet to your eyes and add it, rather than the full height from the feet to the crown.
- If you are using a stationary theodolite, it is not your height that should be added, but the distance from the theodolite's eyepiece to the ground.
- Many trees do not grow strictly vertically; their trunks are tilted. Using the climb angle method, you can adjust it to sloping trees by measuring the distance between you and a point on the ground that is exactly below the top of the tree (not between you and the base of the tree).
- You can improve the accuracy of the Pencil Method and the Elevation Angle Method calculations by taking multiple measurements from different points around the tree.
- This can be a fun activity for students in grades 4-7.
- For more accurate calculations, when using the shadow method instead of a person's height, you can take something whose length you know for sure (for example, a meter ruler or another straight long object).
- Be careful with units (multiply meters by meters or centimeters by centimeters).
- You can easily make a basic clinometer using a protractor. You will find instructions in this article.
Warnings
- The above methods do not work if the tree is growing on a slope. In such cases, specialists use electronic theodolites, which are usually quite expensive.
- While the elevation angle methods, when used correctly, will give you results with an accuracy of half a meter or a meter, they can be easily mistaken, especially if the tree is tilted or growing on a slope. If you need high accuracy, contact the services of an aerial platform.
Any work process related to construction cannot be performed without the use of measuring tools. With their help, a variety of types of construction work are carried out. Especially when these works are finishing. Also, measuring tools are used in the repair process.
In view of the fact that measuring instruments are so popular, and therefore in demand, it is worth talking in more detail about what they are.
About species
There are many types of measuring instruments. However, we will not consider all of them. We will only talk about those that are popular at this time. These include the following tools and devices:
- Electrohydrometer.
- Adhesion meter.
- Microhardness testers.
- Gardner's device.
- Reflectoscope.
- Digital inclinometer.
- Digital roulette.
- Ultrasonic rangefinder.
- Digital instrument for detecting metals.
Let's consider each of these devices in more detail in order to better understand what exactly they are used for.
Electrohydrometer
As you might guess from the name, these devices are designed to determine the moisture level of wood material. They work according to the principle of determining the change in the electrical conductivity of a material following the change in the level of its moisture content. To bring the measurements, you need to stick the needles of the device into the wood surface at some distance from each other.
After that, the scale of the device indicates the level of moisture that is present in the wood. Naturally, the measurement is carried out as a percentage. Due to these indications, the quality of parquet and joinery work is significantly improved. After all, damp wood warps when it dries, and cracks form in the wood covering.
Adhesion meter
With its help, you can determine the level of adhesion with maximum accuracy. In other words, using this device, you can determine the adhesion strength of the paint and varnish material to the surface on which it will be applied in the future. Adhesion can depend on a variety of factors:
- coating thickness;
- the strength of the internal adhesion of the coating and material;
- quality and properties of the applied coating.
You need to understand that different materials that are intended for finishing have a different level of adhesion. And it is for this reason that the use of paints and varnishes, especially if they are expensive, requires appropriate measurements. After all, the range of such materials is so wide that their quality is often in doubt.
Microhardness tester
They are used to determine the hardness of paintwork. This is done by determining the resistance of the analyzed coating in relation to a solid that penetrates into it. The unit of measurement is MPa. It should be noted that the hardness of the paintwork directly depends on the properties of the material itself.
Naturally, such measurements are carried out on wood. Sometimes specially prepared samples of wood material are used for this.
Gardner's device
Such a device is intended for those cases when it becomes necessary to determine the resistance of the paintwork material to abrasion. Outwardly, it resembles a meter-long glass tube with an inner diameter of 30 millimeters. To carry out the measurement, a test or check specimen is placed underneath it at an angle of forty-five degrees.
After that, quartz sand is poured into the tube from a funnel, which has a diameter of five millimeters. The level of resistance is determined by how much sand it took to wear out the top film of the coating.
Reflexoscope
Designed to determine the degree of gloss of the paintwork. Due to this, it is possible to determine with maximum accuracy its quality, which, in turn, is determined by the clarity of the contours of the luminous body located on such a coating.
It should be noted that any paint and varnish coating shines to one degree or another, that is, it reflects light rays. This factor is directly related to the optics and the structure that the surface has. The smoother the coating, the more correctly and directionally the light rays will be reflected. In other words, it shines more.
Digital inclinometer
Using such a device, you can determine the angle of inclination of any surface with maximum accuracy. Naturally, the inclinometer is used in order to determine the angle of inclination of the ceiling, floor or various communications. Such devices are convenient and easy to use. You don't need any special skills to use them.
Digital roulette
Everything is very clear here. This device is a modern analogue of the most common roulette. The digital device allows you to determine the length and width of the structure, surface, and so on with the maximum permissible accuracy.
Ultrasonic Rangefinder
Also a modern analogue of roulette. It can also be used to measure distance. In addition, this device is also suitable for calculating volume and area. This became possible due to the fact that a computing device is built into the device, which also has a memory function and is able to summarize the results.
Digital metal detector
From the name you can guess that this device is used in order to determine the presence of non-ferrous and ferrous metals. But besides this, with the help of this device, you can determine where the electrical wiring is located.
Video. How to choose a tape measure. Builder experience
3. Frontal poll
- Guys, what concepts did we meet in the last lesson?
- At home, it was necessary to draw a table in a notebook in which it was necessary to distribute the following words by columns (physical body, substance, phenomenon): lead, thunder, rails, blizzard, aluminum, dawn, snowstorm, Moon, alcohol, scissors, mercury, snowfall, table, copper, helicopter, oil, boiling, blizzard, shot, flood.
Completion of the table is checked orally.
In the meantime, one student draws up on the blackboard the solution to the task of converting units of measurement.
After that, the children themselves assess the correctness of the assignment.
The most active students who commented and answered confidently, correctly and reasonably should be assessed.
- The third task was creative: to pick up riddles about physical bodies, phenomena, substances.
- Let's play the game "Chain". The condition of the game is as follows: I will ask you a riddle, and you not only have to guess it, but also determine: a body, a substance or a phenomenon. Whoever guesses reads his own. Whoever guesses the riddle of a classmate offers his own, etc. in a chain. And the last condition: riddles are not repeated.
Mystery:
Miracle - bird, scarlet tail
Flew into a flock of stars.
- Well done!
Evaluating the results of homework.
Marks are put in the journal.
The design of a creative task in the form of puzzles, crosswords, drawings is encouraged.
4. Learning new material
- Guys, how long do you think it took us to check the homework?
- Have you still had to take measurements in your everyday life? Which?
- All these listed examples are physical quantities. Today in the lesson we will get to know them in more detail and learn how to measure them. ( Slide 1).
- Write in a notebook the date and topic of the lesson: "Measurement is the basis of technique."
- What measuring devices are familiar to you? What quantities can be measured with their help? ( Slide 2)
- You know a lot of physical devices!
- Do you know how, with their help, to determine the values?
- Check it out?
- I will divide you into groups of 5 people. And each group will experimentally test and confirm their knowledge.
I divide the class into 5 groups with an equal number of children, but different skills and abilities. Since the groups are of different levels, therefore, it is necessary to select differentiated tasks: low, medium, high level. ( Appendix 3
)
When performing the experiment, I remind you of the basic safety rules: working with thermometers, with small objects and with sharp objects.
The speaker (from each group) is assessed, and the correctness of the homework is also taken into account.
- Well done!
- All of you have now proved that you know how to use measuring instruments.
- Tell me, why do we need to know the length and width of the palm?
- Why do we need to know how to determine body weight?
- Where and when did you measure the temperature?
- When else can we measure body volume using a ruler?
- Guys, think about how you can determine the volume of air in the classroom?
- Let's write this formula in a notebook.
- How to determine the volume of a piece of chalk? (Showing the crayon).
- But we are surrounded not only by bodies with the correct geometric shape. For example, a porcelain roller, a Kinder-surprise toy, a spoon, etc.
All items are on display.
- How to determine the volume of an irregularly shaped body? For example, toys "Kinder-surprise"?
- The volume of a small toy is measured with a physical device - a beaker.
- Write down the name of this device in a notebook.
- How to measure body volume with a beaker? To do this, a certain amount of water is poured into a beaker. Immerse the fully investigated body in a beaker of water and notice that the water level has increased. The difference in the readings of the volumes of water will be the desired value - the volume of the body.
- Write the formula down in a notebook:
V = V 1 - V 2, where V 1 is the volume of water in the beaker, and V 2 is the volume of water and the body immersed in it.
- Who will determine the volume of a copper cylinder using a beaker?
Consider the following: this experiment is visible only near a seated audience. Therefore, it is demonstrated slide 3(the result of the experiment).
- Guys, what do all measuring devices have in common? ( Slide 2. Hyperlink).
Next, follow the hyperlink to slide 4. Scale and its characteristics.
- Consider one and the same device for its purpose, but with different scales. On page 9 of the tutorial fig. 11 and 12.
- Guys, tell me if the thermometer readings are the same.
- Which thermometer shows the highest temperature?
- In order to be able to accurately take readings from the device, you need to know its division value.
- Write down the subheading "Division value" in a notebook.
- Division value is the smallest value of a physical quantity that the device can measure.
- In order to correctly determine the division price, there is a rule. ( Slide 5) The same rule is found in the textbook.
We learn to determine the price of division of the beaker scale. ( Slide 6).
- Write down the formula for determining the division price:
C = (a - b) / d. ( Slide 7).
We learn to determine the value of the scale division and measure the readings of the devices. ( Slides 8, 9).
5. Consolidation of the studied material
- Well done!
- Guys, what have you learned in the lesson today?
Assessment of those children who were active in the lesson, taking into account group work.
6. Homework
- Let's write down the homework in the diaries. ( Slide 10).
I distribute cards with assignments of two options. ( Appendix 4
)
I answer the questions of the children if they arose when getting acquainted with the assignments.
In the next lesson, students check each other's work and mark in the margins with a pencil.
“For the rest of the time, we’ll play Understand Me.” ( Slide 11)
- Condition of the game: I ask leading statements, and your task is to guess what is at stake as early as possible. If the answer is correct, the answer will appear on the screen.
- What physical quantity can be measured with their help?
- Where else is this device used?
- The second riddle. ( Slide 12).
- Where and what is this device used for?
- Third riddle: ( Slide 13).
- Have you met this device and where?
The smartest also needs to be appreciated.
- Well done, thank you all for your attention. Many thanks to everyone. ( Slide 14).
Solar radiation meter (luxmeter)
To help technical and scientific workers, many measuring instruments have been developed to ensure accuracy, convenience and efficiency of work. At the same time, for most people, the names of these devices, and even more so the principle of their operation, are often unfamiliar. In this article, we will briefly reveal the purpose of the most common measuring instruments. Information and images of devices were shared with us by the website of one of the suppliers of measuring devices.
Spectrum analyzer is a measuring device that serves to observe and measure the relative distribution of the energy of electrical (electromagnetic) oscillations in a frequency band.
Anemometer- a device designed to measure the speed, volume of air flow in a room. The anemometer is used for sanitary and hygienic analysis of territories.
Balometer- a measuring device for direct measurement of the volumetric air flow rate at large supply and exhaust ventilation grilles.
Voltmeter is a device used to measure voltage.
Gas analyzer- a measuring device for determining the qualitative and quantitative composition of gas mixtures. Gas analyzers are manual or automatic. Examples of gas analyzers: freon leak detector, hydrocarbon fuel leak detector, smoke number analyzer, flue gas analyzer, oxygen meter, hydrogen meter.
Hygrometer Is a measuring device that serves to measure and control air humidity.
Rangefinder- a device that measures distance. The rangefinder also allows you to calculate the area and volume of an object.
Dosimeter- a device designed to detect and measure radioactive radiation.
RLC Meter- a radio measuring device used to determine the admittance of an electrical circuit and impedance parameters. RLC in the name is an abbreviation for the circuit names of elements, the parameters of which can be measured by this device: R - Resistance, C - Capacitance, L - Inductance.
Power meter- a device that is used to measure the power of electromagnetic oscillations of generators, amplifiers, radio transmitters and other devices operating in high-frequency, microwave and optical ranges. Types of meters: absorbed power meters and transmitted power meters.
Harmonic distortion meter- a device designed to measure the total harmonic distortion (harmonic distortion) of signals in radio devices.
Calibrator- a special reference measure that is used for verification, calibration or calibration of measuring instruments.
Ohmmeter, or resistance meter Is an instrument used to measure resistance to electrical current in ohms. Types of ohmmeters depending on the sensitivity: megohmmeters, gigaohmmeters, teraohmmeters, milliohmmeters, microohmmeters.
Current Clamp- a tool that is designed to measure the amount of current flowing in a conductor. Clamps allow measurements without breaking the electrical circuit and without disrupting its operation.
Thickness gauge is a device with which it is possible, with high accuracy and without violating the integrity of the coating, to measure its thickness on a metal surface (for example, a layer of paint or varnish, a layer of rust, a primer, or any other non-metallic coating applied to a metal surface).
Light meter Is a device for measuring the degree of illumination in the visible region of the spectrum. Light meters are digital, highly sensitive devices such as light meter, brightness meter, pulse meter, UV radiometer.
Pressure gauge- a device that measures the pressure of liquids and gases. Types of pressure gauges: general technical, corrosion-resistant, pressure gauges, electrical contact.
Multimeter Is a portable voltmeter that performs several functions at the same time. The multimeter is designed to measure AC and DC voltage, current, resistance, frequency, temperature, and also allows for continuity and diode testing.
Oscilloscope Is a measuring device that allows you to observe and record, measure the amplitude and time parameters of an electrical signal. Types of oscilloscopes: analog and digital, portable and desktop
Pyrometer is a device for non-contact measurement of the temperature of an object. The principle of operation of the pyrometer is based on measuring the power of the thermal radiation of the measuring object in the range of infrared radiation and visible light. The optical resolution affects the accuracy of temperature measurement at a distance.
Tachometer Is a device that allows you to measure the speed of rotation and the number of revolutions of rotating mechanisms. Types of tachometers: contact and non-contact.
Thermal imager Is a device designed to observe heated objects by their own thermal radiation. A thermal imager allows you to convert infrared radiation into electrical signals, which in turn, after amplification and automatic processing, are converted into a visible image of objects.
Thermohygrometer Is a measuring device that simultaneously performs the functions of measuring temperature and humidity.
Trace detector Is a universal measuring device that allows to determine the location and direction of cable lines and metal pipelines on the ground, as well as to determine the place and nature of their damage.
pH meter Is a measuring device designed to measure the pH value.
Frequency counter- a measuring device for determining the frequency of the periodic process or the frequencies of the harmonic components of the signal spectrum.
Sound level meter- a device for measuring sound vibrations.
Table: Units of measurement and designations of some physical quantities.
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