FOCUS! Hold microscope close Page 1 Hold microscope close Set down with handle close and 4x objective under tube Sit down Remove ____________________ slide from case and clip onto stage Tilt body back carefully while holding base firmly Open diaphragm Level mirror (flat side up easier) Carefully turn top of coarse knob toward tube until it STOPs Look through eyepiece lens, down tube Move mirror around slowly and carefully until the field of view is bright Center specimen on slide over the hole or lens in stage Look down tube while slowly turning coarse knob away from tube until specimen is in focus Explain in complete statement(s) on your paper! what are you changing when turning the knob to focus on the image? Turning the knob towards the tube moves the… Turning the knob away from the tube moves the…

FOCUS! Page 2 While looking through tube at specimen, turn the coarse knob slowly toward and away from the tube Observe how different threads come into focus as you move the objective lens up and down Depth of field is the height in focus at one time Explain in complete statement(s) on your paper! Is the depth of field large enough to focus on all threads at the same time? Depth of field is large enough to focus… How wide (# twists) is your field of view with the 4x objective lens? Field of view with the 4x objective lens is ______ wide Magnification = eyepiece lens power * objective lens. Calculate magnification using the 10x eyepiece and 4x objective lenses.

FOCUS! Page 3 Carefully touch both ends of slide and move VERY SLOWLY to see other parts of specimen Explain in complete statement(s) on your paper! Which way does the image move in the field of view when you move slide up? When I move the slide up, the image moves… Which way does the image move in the field of view when you move slide down? When I move the slide down, the image moves… Which way does the image move in the field of view when you move slide right? When I move the slide right, the image moves… Which way does the image move in the field of view when you move slide left? When I move the slide left, the image moves…

FOCUS! Page 4 Increase magnification by carefully rotating nosepiece so that 10x objective goes directly under the tube ONLY USE FINE KNOB WITH 10X AND 40X OBEJCTIVES Turn FINE KNOB toward and away from tube slowly, while looking through eyepiece until specimen is in focus If you cannot get specimen in focus, rotate nosepiece so that 4x objective lens is under tube and use COARSE KNOB to focus, then rotate 10x lens back under tube. Is the depth of field large enough to focus on all threads at the same time, or can you only focus on smaller strands? Depth of field is large enough to focus… What can you conclude about how the depth of field changes as you increase magnification? As magnification increases, depth of field… How wide (# twists) is your field of view with the 10x objective lens? Field of view with the 10x objective lens is ______ wide What can you conclude about how the field of view changes as you increase magnification? As magnification increases, field of view… 14. Magnification = eyepiece lens power * objective lens. Calculate magnification using the 10x eyepiece and 10x objective lenses.

FOCUS! Page 5 Increase magnification by carefully rotating nosepiece so that 40x objective goes directly under the tube ONLY USE FINE KNOB WITH 10X AND 40X OBEJCTIVES Turn FINE KNOB toward and away from tube slowly, while looking through eyepiece until specimen is in focus If you cannot get specimen in focus, rotate nosepiece so that 10x objective lens is under tube and use FINE KNOB to focus, then rotate 10x lens back under tube. Is the depth of field large enough to focus on one thread at the same time, or can you only focus on smaller strands? Depth of field is large enough to focus… What can you conclude about how the depth of field changes as you increase magnification? As magnification increases, depth of field… How wide (# twists) is your field of view with the 40x objective lens? Field of view with the 40x objective lens is ______ wide What can you conclude about how the field of view changes as you increase magnification? As magnification increases, field of view… Magnification = eyepiece lens power * objective lens. Calculate magnification using the 10x eyepiece and 40x objective lenses.