Laboratory Equipment Mrs. Bordeaux’s Lab License Course Part II

Beakers

Using beakers: Use beakers for holding and pouring liquids and heating liquids on a hot plate Do not use a beaker to measure liquids (use a graduated cylinder instead) Use a beaker that holds at least twice as much liquid as you will be using

Graduated Cylinders

Using graduated cylinders: Use a graduated cylinder to measure the volume of liquids Make sure the cylinder is on a flat surface When reading the scale on the cylinder, make sure your eyes are level with the top of the liquid The surface of the liquid will be curved, read the scale at the bottom of the curve (meniscus)(meniscus) Find the volume of a solid object by measuring the change in volume after you add the object to the cylinder

Read the measurement at the meniscus

Test Tubes

Using test tubes: Use test tubes for small amounts of substances only Do not use a test tube to measure the volume of liquids Use a test tube to heat substances over a flame. Remember to point it away from yourself and others.

Test Tube Holders:

Using test tube holders: Use test tube holders when heating a substance in a test tube or if a substance in a test tube is dangerous to touch Make sure the holder tightly grips the test tube so it will not slip Make sure the holder is above the surface of the substance in the test tube so you can observe the substance

Test Tube Racks

Using test tube racks: Use a test tube rack for organizing test tubes before, during and after an experiment Use a test tube rack to keep test tubes upright to keep them from spilling

Forceps

Using Forceps: Use forceps to pick up or hold very small objects or objects that should not be touched with your hands Do not use forceps to hold anything over a flame. Plastic forceps will melt and metal forceps will conduct heat and burn you

Hot Plates

Using hot plates: Use a hot plate when a substance needs to be kept warmer than room temperature for a long period of time Use a hot plate instead of a Bunsen burner or candle when you need to carefully control temperature Always use “hot hands” safety mitts or oven mitts when handling something that has been heated on a hot plate

Spring Scales

Using a spring scale: Use a spring scale to measure force pulling on the scale Use a spring scale to measure the force of gravity exerted on an object by Earth Continued

Using a spring scale (continued): To measure a force accurately, a spring scale must be zeroed before it is used. The scale is zeroed when there is no weight attached and the indicator is at zero Do not attach a weight that is too light or too heavy for the scale to measure. One that is too light will not register and one that is too heavy can damage the scale

Balances

Using a triple beam balance: 1. Zero the balance. (move all indicators to the far left) 2. Move the largest indicator first. When you reach a measurement that makes the balance go down, back up one notch. 3. Repeat for the second indicator and then use the last indicator to fine tune your measure until the line lines up on the end. 4. Read your measure beginning with the largest number and adding each measure.

Beams on a balance: Largest indicator (Read at center arrow) Second indicator This indicator is precise to a tenth of a gram.

Other Equipment You May See In The Lab

Bunsen Burner Crucible Droppers Erlenmeyer Flasks Funnels Thermometers

Petri Dishes Electrophoresis Gel Chamber Power Supply