Laboratory Instruments Johnny Appleseed 2 nd Hour Glass

Laboratory Instruments Johnny Appleseed 2 nd Hour

Glass Instruments • Beakers • Graduated Cylinders • Thermometers • Test Tubes

Beakers Use Container used for stirring, mixing and heating liquids; measures m. L Pros -- Measure large amounts of liquids -- Thick top with easy pour spout and flat bottom -- Can hold corrosive chemicals Cons -- Unable to measure less than 10 m. L -- High rate of evaporation -- Not as accurate as graduated cylinders

Graduated Cylinders Use Accurately measures out volumes of liquids in m. L Pros -- Accurately measures liquids -- Stable base -- Easy pour spout Cons -- Meniscus may be difficult to interpret -- Only measures small amounts of liquids -- Base may be uneven after cleaning

Thermometers Use Measures temperature in Celsius and Fahrenheit Pros -- Comes in a variety of shapes and sizes -- Accurately measures the temperature -- Thermometers have improved over time Cons -- Many glass thermometers contain poisonous Mercury liquid -- May be difficult to read -- Choice of thermometer may create difficulty

Test Tubes Uses Multipurpose laboratory instrument Pros -- Come in different sizes and specialties -- Inexpensive -- Can be used with solids, liquids, and gases Cons -- Easily breakable -- Not a measurement tool -- Every test tube holds a different amount

Mechanical Instruments • Triple Beam Balance • Pan Balance • Rulers • Non-Glass Thermometers • Clocks • Microscopes

Triple Beam Balances Uses Measures mass Pros -- More accurate than a pan balance -- Finds exact weight of an object -- Rugged and inexpensive Cons -- Balance must be zeroed for accurate results -- Reading the weight takes time and practice -- Must be used on a level surface

Pan Balances Uses Measures mass Pros -- Can measure relative mass and exact weight -- Simple measuring tool -- Reading the weight is easier than a triple beam balance Cons -- More time consuming to use -- Balance must be zeroed for accurate results -- Must be on a level surface

Rulers Use To measure length in cm, mm, in, m, yd, ft Pros -- Measuring sticks can have more than one unit of measure -- Simple to use -- Easy to read Cons -- Only useful on flat surfaces -- Must know how to read for accuracy -- The zero is not always the end of the ruler

Thermometers Use Measures temperature in Celsius and Fahrenheit Pros -- Comes in multiple sizes and shapes -- Accurately measures the temperature -- Thermometers have improved over time Cons -- Digital thermometers break when exposed to water -- May be difficult to read -- Choice of thermometer may create difficulty

Clocks Uses Measures time in hours, minutes, and seconds Pros -- Measures a length of time -- Tells the time of the day -- Accurately measures specific minutes and seconds Cons -- Must reference clock to be accurate -- Dying batteries slow or stop the time -- Start time must be zeroed

Microscopes Uses Allows magnification of small items for human viewing Pros -- Magnification can range from 20 x to 100 x its original size -- Allows humans to understand microscopic organisms -- Shows details Cons -- Slides break easily -- Expensive -- Without proper training, difficult to see specimen

References • Wikipedia