See here. For an overview of commercially available density meters and their features and benefits, see here. The following describes the parts of a benchtop density meter which all such devices have in common.
For a comparison of the different oscillating U-tube measuring methods, see here. The sensor is the heart of the digital density meter. Typically, the sensors are mostly straight or U-shaped tubes. They can be made of glass, e. It is linked to the housing of the density meter by elastic supports and acts like a mechanical filter for external oscillations. The countermass has a resonance frequency that lies far below the frequencies used for density measurement.
The countermass also ensures that the nodal points of the tube are constantly in position. The sample volume is set by the nodal points and therefore only the mass changes depending on the filled fluid while the volume remains stable.
In case of sensors made of glass a built-in reference oscillator eliminates not only long-term drifts due to the aging effects of the material but also temperature changes that influence the elasticity.
A reference oscillator therefore means that only one single adjustment is used to cover the whole temperature range and provides the possibility to perform temperature scans of a sample. For users who measure at just one temperature or have time to perform a density adjustments at different temperatures, if required, there are density meters without a reference oscillator which also achieve excellent results at up to 4-digit accuracy.
Temperature regulation of the cell is typically performed with Peltier elements, which have now displaced water baths. This advantageous technology has now replaced the use of water baths. Peltier elements make use of the Peltier effect, a heat flux due to electric current: One side of a Peltier element heats up while the other side cools down depending on the direction of the current flow [24] Peltier elements therefore allow both effective heating and cooling of the measuring cell and additionally provide precise and fast temperature regulation.
Figure 7: Pulsed Excitation Method: After reaching a stable oscillation, the excitation is switched off and fades out. The excitation and fade-out sequence is repeated continuously. Consistently following a few simple guidelines will help you on your way to accurate and reproducible density results. Since Anton Paar GmbH has specialized in providing highly accurate and reliable density meters for research and industry.
This brochure sums up our experience and insights into measurement practice gained in over forty years. Follow these guidelines and you will be well on your way to accurate and reproducible density results. We use cookies on our website. Some of them are necessary e. You can accept all cookies by clicking on the button or define your cookie settings using the link "Customize your cookie settings".
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Overview-table: Density measurement techniques 2. What is density? Density definition 2. What affects density? Anomaly of water 2. Density units 3. Density measurement 3. History 3. Overview of density measurement techniques 3. In-depth: Measuring density with a digital density meter 3.
Parts of a digital density meter 4. How to ensure good density results? Density redefined Anton Paar redefines digital density measurement and shapes the future of the technique once again. Density measurement techniques These are the methods for measuring density. Density meters Solutions from the market leader in density measurement. Customer success stories Read about the individual success stories behind the products.
Measuring the density of Density tables Here you will find the official density tables for the following substances: Density of ammonium sulfate Density of hydrochloric acid Density of ethanol Density of sucrose Density of tartaric acid Density of urea. Overview table: Density measurement techniques Find out more about each device type by clicking the title. See Density units for more information Read more about the relationship between mass and density. Figure 1: The effects of density. Air pressure and altitude The local air pressure and altitude also have an impact on the density of liquids and modern density meters compensate for these influencing factors so they do not affect the results.
Viscosity Depending on how you measure density, the viscosity of the substance may affect the result. Anomaly of water Water is a unique liquid and reaches the density maximum at a temperature of 3. Density units A physical property like density is investigated for several reasons and is therefore reported in several units. Others Depending on the measurement — and also on the industry — different units are used.
Density measurement History. Archimedes — the Eureka moment Density measurement has a long history — it actually dates back years to the times of King Hieron II of Syracuse. Hypatia — the hydrometer In the 4th century Hypatia of Alexandria, a philosopher, mathematician, teacher, and first female contributor to mathematics in ancient times, developed the hydrometer which was then called a hydroscope for measuring the density of liquids.
Galileo Galilei — the hydrostatic balance Weighing precious metals in air and then in water was a common practice among jewelers in Europe when Galileo Galilei, the famous Italian mathematician, astronomer, and physicist, described an instrument in the 16th century that is still used for high-precision density measurements today: The hydrostatic balance.
Overview of density measurement techniques. Hydrometers A hydrometer is a floating glass body with a bulb filled with a metal weight and a cylindrical stem with a scale. Figure 2: Hydrometer immersed in a sample. The density of the sample can be read from the scale. Pycnometers A pycnometer consists of a glass flask and a stopper sometimes with an integrated thermometer.
Figure 3: Pycnometer on a balance. Hydrostatic balances The hydrostatic balance is based on the Archimedes principle. Figure 4: Hydrostatic balance. Digital density meters Figure 5: Digital density meter. In-depth: Measuring density with a digital density meter Not all density meters are created equal.
The main components of such a system are a constant gamma source usually radium and a detector. Variations in radiation passing through a fixed volume of flowing liquid is converted into a proportional electrical signal by the detector. This type of measurement is often used in dredging where the density of the mud indicates the effectiveness of the dredging vessel. Damping of a vibrating object in a fluid will increase as the density of the fluid increases.
An object is vibrated from an external energy source. The object may be an immersed reed or plate. Density is measured from one of two procedures: 1. Changes in the natural frequency of vibration can be measured when the object is energised constantly.
Changes in the amplitude of vibration can be measured when the object is struck periodically, like a bell. Constant level overflow tanks are the simplest for measuring as only one differential pressure transmitter is required.
However applications with level or static pressure variations require compensation. Increases in temperature cause expansion of a liquid, altering its density.
Not all liquids expand at the same rate. A specific gravity measurement must be corrected for temperature effects in order to be completely accurate in terms of reference conditions for density and concentration, although in most cases this is not practical.
Materials engineers carefully consider the density of materials for construction in these contexts. For example, the bodies of some lightweight laptop computers are made of aluminum, one of the least dense metals. Lightweight tennis rackets contain titanium, another low-density metal. Figure 2: Equivalent masses of aluminum Al and zinc Zn metal. The zinc metal occupies a much smaller volume due to its higher density.
General Chemistry. Determining the Density of a Solid and Liquid. To learn more about our GDPR policies click here. If you want more info regarding data storage, please contact gdpr jove. Your access has now expired. Provide feedback to your librarian. If you have any questions, please do not hesitate to reach out to our customer success team. Login processing This is a sample clip. Sign in or start your free trial. Previous Video Next Video. Overview Source: Laboratory of Dr. Michael Evans — Georgia Institute of Technology The ratio of the mass of a substance to its volume is known as the mass density or, simply, the density of the substance.
Log in or Start trial to access full content. Determination of the Density of Liquid Ethanol Place a clean and dry mL volumetric flask on an analytical balance. The balance should read 0. Use a buret funnel to add 45 mL of liquid ethanol to the volumetric flask. Weigh the volumetric flask again and record the mass of the ethanol. For best results, repeat steps 1. Record the exact volume of the water. Place the cylinder and water on an analytical balance.
Add approximately 10 zinc pellets to the graduated cylinder. Record the new volume of the water plus zinc pellets using the liquid level after addition of the zinc Figure 1. Figure 1. Zinc added to the cylinder on the right causes the water level to be displaced upward. Weigh the cylinder, water, and zinc pellets on the balance.
Record the mass of the zinc pellets. For best results, repeat steps 2. All matter has mass, and that mass occupies a specific volume. Thanks for watching! Please enter your institutional email to check if you have access to this content. Please create an account to get access. Forgot Password? Please enter your email address so we may send you a link to reset your password.
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