LAB EQUIPMENT Scientists use “tools”, or pieces of lab equipment to perform certain tasks when conducting an experiment

ACCURACY VS PRECISION It is very important that scientists record and report their measurements (data) as accurately and precisely as possible

ACCURACY VS PRECISION Accuracy – how correct a measurement is; the more correct a measurement is, the more accurate it is. Precision – the exactness of a measurement; determined by the number of increments included in the measurement (Ex: decimal places)

Example

Each of five students used the same ruler to measure the length of the same pencil. These data resulted: 15.33 cm, 15.34 cm, 15.33 cm, 15.33 cm, 15.34 cm. The actual length of the pencil was 15.85 cm. Describe whether accuracy and precision are each good or poor for these measurements.

Equipment and Function

THERMOMETER Measures temperature Read at EYE LEVEL! Allow time for accurate reading to occur Keep the bulb submerged and away from the sides of the container

COMPOUND MICROSCOPE Used to magnify objects Light microscope – light rays pass through the specimen and magnify the image. Useful to view cells.

MICROSCOPE SLIDE/ SLIP COVER Used to hold and cover specimens to be viewed under a microscope

ELECTRON MICROSCOPE Used by scientists to view objects too small to be seen through a light microscope. Uses electron beams instead of light. Much higher resolution (Clearer images at higher magnification)

LIGHT VS ELECTRON Light Electron Living Objects Natural color and movement can be seen Poor resolution Easy to use Inexpensive Objects CANNOT be alive Black and white images, no movement Excellent resolution Highly trained user Very expensive

METRIC RULER Used to measure length The more lines there are, the more precise it is!

TRIPLE BEAM BALANCE Measures mass

LIQUIDS In the laboratory, glassware is used for measuring and dispensing liquids. Can anyone tell me why glass is the best choice?

LIQUIDS Some tools are fine for dispensing liquid, but not for measuring.

ERLENMEYER FLASK Holding, storing, and transferring large amounts of liquid NOT ACCURATE!

BEAKER Holding, storing, and transferring large amounts of liquid NOT ACCURATE!

BURETTE/ PIPETTE Dispenses measured amounts of liquid Very accurate and precise!

PIPETTE/DROPPER Dispenses small amounts of liquid in drops at a time

GRADUATED CYLINDER Accurately measures liquid in milliliters Read volume at eye level at the meniscus – the curve in the surface of a liquid.

TEST TUBE/ ACCESSORIES Holding, mixing, and storing small amounts of liquid Place in a test tube rack for holding Use tongs – not bare hands – for handling Clean with a test tube brush

PETRI DISH Grow cultures Observe small animal behaviors

MORTAR AND PESTLE Used to crush and grind large substances Often used in pharmacies

SPATULA Used to transfer small amounts of powder or granular substance

HOT PLATE Used to heat liquids in the lab

HAND LENS Used to magnify objects or look at them more closely

DISSECTION KIT

FORCEPS Used to hold a specimen or parts of a specimen while studying

PROBE Used to gently manipulate a specimen

SCALPEL Used to make fine cuts in a specimen

DISSECTION TRAY Used to hold specimens for dissection and provide a way to pin them.

DISSECTING PINS Used to hold a specimen in the dissecting tray

DISSECTING SCISSORS Used to cut specimens for dissecting Why is it so important that they be especially sharp?

BUNSEN BURNER Used as a source of heat/ flame in the lab Uses gas to produce a flame Reaches temperatures up to 1500 degrees Celsius!

STRIKER Used to light a bunsen burner

FUNNEL Used to transfer liquids or powders without spilling

GLASS STIRRING ROD Used to stir liquids

SAFETY GOGGLES Protect eyes from liquids, glass, etc in the lab

LAB APRON Used to protect clothing from spills in the laboratory