Tools of the Biologist

In order to observe, discover, and explore, scientists use many different pieces of lab equipment. A.Measuring Length 1. Meter stick, Ruler Each marked line represents 1 cm. The smaller lines between cm are mm. There are 10 mm in 1 cm There are 100 cm in 1 m

B. Measuring Volume 1.Graduated Cylinder Used to measure exact volumes To Use: Fill to the appropriate level. Note that liquid in a glass graduate cylinder curves upward at the edges. This is called the MENISCUS. Read the volume at the bottom of the meniscus when looking at eye level.

12 mL 16 mL 14 mL Pay attention to the scale of the graduate cylinder (How much the lines go up by)

B. Measuring Volume 2. Beaker Used to measure a approximate volume To use: fill with the appropriate volume There will not be much of a meniscus Read at eye level.

B. Measuring Volume 3. Erlenmeyer and Florence Flasks Used to measure an approximate volume And/or to mix solutions To use: same as beaker Erlenmeyer Florence

B. Measuring Volume 4. Pipette Used to measure an approximate volume Measures one drop at a time To use: (to fill) submerge, gently squeeze and release (to release) carefully squeeze 1 drop at a time

C. Measuring Mass 4. Electronic Balance Used to measure an exact mass To use: Turn on, zero the balance, set to correct unit, carefully place sample on tray. If sample is placed in a container subtract the mass of the container from the total mass

D. Tools for Dissection 1. Dissecting Pan Used to hold specimens in place To use: Lay the specimen on the tray and pin to the rubber bottom

D. Tools for Dissection 2. Dissecting Needle (Probe) Multi-purpose tools to move parts of the specimen

D. Tools for Dissection 3. Scalpel Use: to make precision cuts and/or take samples

D. Tools for Dissection 4. Forceps Use: to grasp and manipulate parts of a specimen

E. Using Chemicals 1. Test Tube/Test tube rack Use: to carry out chemical reactions When not in use, put in test tube rack

E. Using Chemicals 1. Test Tube Holder Use: to hold and move test tubes Squeeze handle so the clamp opens Release handles so the clamp closes around test tube

E. Using Chemicals 1. Test Tube Brush Use: cleans inside of test tube

F. Observing Specimens and Samples 1. Petri Dish Use: small dish to hold samples and/or grow bacterial samples.

G. Safety Equipment 1. Safety Goggles Use: Place over your eyes for protection

G. Safety Equipment 1. Safety Gloves Use: Place over your hands for protection from heat, chemicals, body fluids, etc

G. Observation 1. Compound Light Microscope Use: enlargement of microscopic specimens

1. Compound Light Microscope -Magnifies specimen 100s of times -“Compound” means it has several lenses 2. How to Use a Microscope -Always carry the microscope by the arm while supporting the base -Position the microscope so the arm is near to you -ALWAYS START WITH THE LOWEST POWER MAGNIFICATION

2. How to Use a Microscope (cont) -Center the slide on the stage -Center the specimen in the field of view (remember the image is inverted) -Use the coarse adjustment to focus the slide - -Once the slide is in focus, switch to a higher power then refocus with fine adjustment -ONLY USE THE FINE ADJUSTEMENT ONCE YOU’VE SWITCHED TO THE HIGH POWER LENS – IF NOT THE SLIDE WILL CRACK

Making a Wet Mount Slide Wet mounts are microscope slides that contain a specimen mounted in water. A cover slip (or cover glass) is used to flatten the specimen and the water drop. 1.Obtain a clean microscope slide and cover slip. Hold cover slips only by the edges. 2.Add a small drop of water to the slide. 3.Place the specimen in the drop of water. 4.Hold the cover slip at a 45˚ angle next to the drop of water, slide it over until it hits the water. Place it onto the water. This helps prevent air bubbles.

Adding a Stain/Chemical to Wet Mount Slide Stains: Chemicals added to a slide in order to see parts of a specimen more clearly.

Adding a Stain/Chemical to Wet Mount Slide Stains: Chemicals added to a slide in order to see parts of a specimen more clearly. 1.After making a wet mount slide, place a drop of stain on one side of the cover slip 2.Gently touch the other side of the cover slip with a piece of paper towel 3.The paper towel will “pull” the stain under the coverslip

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