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1.9

Minor Versionm

by Vishal Bhatt

Introduction

Observe the cells of an onion with a microscope that you made using some simple material that can be acquired quite easily. The first simple microscopes began to appear in the 13th century, but the optical properties of water have been used to magnify things for thousands of years.

Video Overview

    • Exercise caution while using scissors, cutters and glass items.

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  1. Mark a small square with an pen
    • Mark a small square with an pen

    • Use a blade to cut out the square

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    • Cut out a small strip of tape. Fold it, and cut out a hole in the center.

    • Stick the tape over the hole

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    • Cut out a small foam piece of the came size as the hole you made in the ice cream stick. Use a scissor of make a hole in the foam

    • If your fingers are unstable, you may use forceps/tweezers to place the bead. If you are using your bear hands, make sure they are thoroughly clean

    • Stick the foam in the hole and you microscope is ready to play

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    • Cut about an eighth of an onion. Take out one slice from the cut part to get the appropriate size of an onion peel

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    • Bend the onion slice towards the concave side to make a small tear.

    • Carefully detach one side of the onion slice and pull out the transparent peel.

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    • Cut the onion peel to a size smaller than that of the cover slips.

    • Wet the glass slide first with water and place the onion peel on it carefully.

    • Try to make the space between the onion peel and the slide free of air bubbles as much as possible. That is why we wet the slide.

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    • Add a few drops of stainer (safranine or iodine) to the peel and keep it open for 30 seconds.

    • Now gently place a glass cover slip over the peel. To avoid entrapment of air bubbles, make sure to keep cover slip at an angle initially while placing it on slide.

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    • Blot out the excess stainer from the sides using soft cotton cloth or tissue paper.

    • Do not put too much pressure while blotting out the excess stainer. You might beak the glass slide.

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    • Cut out a small rectangular piece from the cardboard strip equal to or larger than the size of the cover slip.

    • Add rubber bands to secure the slide on the cardboard.

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    • The side with the full strip of tape is the viewing side i.e., towards your eye.

    • The bead microscope should be in contact with the object. Adjust the position of the bead inside the hole to get a clear image of the onion peel cells.

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    • Bead falling out from the cardboard because of hole being too big .

    • Glass slide and cover slip not clean due to which image is not clear

    • Didn't wet the slide initially which causes air bubbles to get trapped beneath the onion peel

    • Air bubbles appearing after putting the cover slip on the peel. Onion peel should be less than the size of the cover slip

    • Cover slip moving while hovering the microscope over it. Make sure excess safranine or iodine has been blotted out.

    • Image appearing blurry. Make sure the glass bead is clean and not too much of it is inside the hole from the side facing the slide.

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    • After looking at the plant cells through the bead microscope, can you tell what the different components of a cell structure are (even if you see only one)? What could be the biggest structure in a plant cell?

    • Compare the structure of a plant cell to an animal cell. What differences do you notice?

    • Compare the magnification required to see different cell organelles and guess the approximate difference in sizes of different components of the cell.

    • Hold the bead an arms leant away from your eye. Look at something that is really far away, what is the image that you see on the surface of the bead .

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    • Use a garlic peel instead of the onion peel.

    • Make the microscope with a different sized bead

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    • A photograph of the peel under the microscope

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Finish Line

Suhail Ahanger

Member since: 05/02/2017

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55 Guides authored

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