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Click on a name below to read a description of the instrument and what it is used for.
Buret | Electronic Balance | Graduated Cylinder | Thermometer | Volumetric Flask | Volumetric Pipet
Burets are usually made of glass and contain many markings, called graduations. Burets are used to measure and dispense liquid volumes accurately. Usually each major division is marked with a number, and the reader must count the number of graduations present between each major division. Simple division reveals the volume represented by each mark on the cylinder. For instance, if the major divisions are 10mL, 20mL, 30mL, etc., and there are ten graduations in between each of those divisions, then each line represents 1mL (10mL ÷ 10 divisions = 1mL/division).
Burets are often used to determine the concentration of a solution by dispensing a solution with a known concentration. This process is known as titration.
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Electronic balances are used to measure the mass of substances accurately. Older balances are the triple-beam and four-beam balances. These balances operated by placing a known quantity of mass on one side of the balance fulcrum, and causing the item be measured to "balance" on the fulcrum. Electronic balances perform this measurement with the help of electronics. The balance is calibrated so that the amount of resistance placed on the balance pan corresponds to a given mass value (which is then displayed on the LCD readout. Learn more about the balance controls.
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Graduated cylinders are usually made of glass and contain many markings, called graduations. Graduated cylinders are used to measure liquid volumes accurately. Usually each major division is marked with a number, and the reader must count the number of graduations present between each major division. Simple division reveals the volume represented by each mark on the cylinder. For instance, if the major divisions are 10mL, 20mL, 30mL, etc., and there are ten graduations in between each of those divisions, then each line represents 1mL (10mL ÷ 10 divisions = 1mL/division). 
Thermometers are sealed glass tubes containing either mercury or a colored alcohol solution. Thermometers are used to measure the temperature of substances. Thermometers containing the colored alcohol solution will usually have red, blue, or green bulbs. Mercury thermometers have a silver colored bulb (if you come across one of these, notify the instructor immediately). Particular attention must be paid to what scale temperature is measured in (°C or °F) and what each graduation on the thermometer represents. The method for determining this is discussed under graduated cylinders above. 
Volumetric flasks are made of glass and consist of two main parts: a tear-drop shaped base and a long cylindrical neck that has a single circular etch around it. Volumetric flasks are used for preparing solutions and diluting chemicals. They are instruments designed to measure liquid volume very accurately. However, each flask is designed to only measure one volume. Each volumetric flask is unique; the etched line marks the level at which the flask will contain the designated volume. Volumetric flasks come in many different sizes, from tiny 10mL flasks to large 2,000mL flasks. The size of the flask used depends on the amount of solution that needs prepared/diluted.
Volumetric pipets are glass tubes used to measure small liquid volumes very accurately. However, each pipet is designed to only measure one volume. Each volumetric pipet is unique. Some are straight tubes, while others have a bulb-shaped reservoir in the middle (see above picture). The etched line on the pipet marks the level at which the pipet will contain the designated volume. Volumetric pipets come in many different sizes, depending on the amount of liquid that needs to be measured/transferred.Back to: |
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