A graduated cylinder, measuring cylinder or mixing cylinder is a piece of laboratory equipment used to measure the volume of a liquid. Graduated cylinders are generally more accurate and precise than laboratory flasks and beakers. However, they are less accurate and precise than volumetric glassware, such as a volumetric flask or volumetric pipette. For these reasons, graduated cylinders should not be used to perform volumetric analysis. Graduated cylinders are sometimes used to indirectly measure the volume of a solid by measuring the displacement of a liquid.
Often, the largest graduated cylinders are made of polypropylene for its excellent chemical resistance or polymethylpentene for its transparency, making them lighter and less fragile than glass. Polypropylene (PP) is easy to repeatedly autoclave; however, autoclaving in excess of about 130 °C (266 °F) (depending on the chemical formulation: typical commercial grade polypropylene melts in excess of 160 °C (320 °F)),can warp or damage polypropylene graduated cylinders, affecting accuracy.
A Mohr pipette, also known as a Graduated pipette,is a type of pipette used to measure the volume of the liquid dispensed, although not as accurately as a volumetric pipette. These use a series of marked lines (as on a graduated cylinder) to indicate the different volumes. They come in a variety of sizes, and are used much like a burette, in that the volume is found by calculating the difference of the liquid level before and after.
The last graduation mark is some distance from the tip, to avoid errors in measuring the narrower volume of the nozzle. It was invented by Karl Friedrich Mohr, the Father of Volumetric Analysis.
The Fahrenheit hydrometer is a device used to measure the density of a liquid. It was invented by Daniel Gabriel Fahrenheit (1686 – 1736), better known for his work in thermometry.
The Fahrenheit hydrometer is a constant-volume device that will float in water. In the figure shown here, the hydrometer is floating vertically in a cylinder containing a liquid. At the bottom of the hydrometer is a weighted bulb and at the top is a pan for small weights. To use the hydrometer, one first accurately determines its weight (W) while it is dry. Next, the device is placed in water, and a weight (w) sufficient to sink a marked point on the rod to the water-line is placed on the pan. At that point, the weight of water displaced by the instrument equals W + w. The hydrometer is then removed, wiped dry, and placed in the liquid whose density is to be determined. A weight (x) sufficient to sink the hydrometer to the same marked point is placed in the pan. The density (D) of the second liquid is then given by D = (W + x) / (W + w).
Laboratory glassware refers to a variety of equipment, traditionally made of glass, used for scientific experiments and other work in science, especially in chemistry and biology laboratories.
Science of drugs including their origin, composition, pharmacokinetics,
pharmacodynamics, therapeutic use, and toxicology.
Pharmacology (from Greek φάρμακον, pharmakon, "poison" in classic Greek; "drug" in modern Greek; and -λογία, -logia "study of", "knowledge of") is the branch of medicine and biology concerned with the study of drug action, where a drug can be broadly defined as any man-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals.
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve several billion users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW), the infrastructure to support email, and peer-to-peer networks.
Most traditional communications media including telephone, music, film, and television are being reshaped or redefined by the Internet, giving birth to new services such as voice over Internet Protocol (VoIP) and Internet Protocol television (IPTV). Newspaper, book and other print publishing are adapting to website technology, or are reshaped into blogging and web feeds. The Internet has enabled and accelerated new forms of human interactions through instant messaging, Internet forums, and social networking. Online shopping has boomed both for major retail outlets and small artisans and traders. Business-to-business and financial services on the Internet affect supply chains across entire industries.