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by Suhail Ahanger

Introduction

Prepare a slide of Onion peel and stain it to observe the epithelial cells, using your DIY Microscope.

    • DIY Microscope is a prerequisite TACtivity that has to be completed before commencing this TACtivity. In the DIY Microscope, you create your own Microscope with two glass beads of 4.5 and 2.5mm diameter. You also learn how to focus the microscope. Review DIY Microscope for details.

    • Scissors and cutters have functional sharp edges. Handle carefully.

  1. Remove the cover carefully from both side of the slide. Wipe the glass slide with tissue paper. Add a drop of water in the center of the slide.
    • Remove the cover carefully from both side of the slide.

    • Wipe the glass slide with tissue paper.

    • Add a drop of water in the center of the slide.

  2. Separate the layers from the cut onion. Use any one layer to take the peel off. Use fresh sample for better results. Use fresh sample for better results.
    • Separate the layers from the cut onion. Use any one layer to take the peel off.

    • Use fresh sample for better results.

  3. Bend the onion slice towards the concave side to make a small tear. Carefully detach one side of the onion slice to reveal the transparent peel. Carefully detach one side of the onion slice to reveal the transparent peel.
    • Bend the onion slice towards the concave side to make a small tear.

    • Carefully detach one side of the onion slice to reveal the transparent peel.

  4. Cut the small portion of a transparent layer of the onion sample. The size of the onion peel should be less than the size of cover slip.
    • Cut the small portion of a transparent layer of the onion sample.

    • The size of the onion peel should be less than the size of cover slip.

    • Carefully, place the sample on the slide and make sure to stretch it properly to avoid any air bubbles getting trapped under the peel.

  5. Add 2-3 drops of safranin and leave for few seconds. Place the cover slip a few millimetres away from the sample at an angle. Slowly, move the top edge of the coverslip towards the sample and cover it fully.
    • Add 2-3 drops of safranin and leave for few seconds.

    • Place the cover slip a few millimetres away from the sample at an angle.

    • Slowly, move the top edge of the coverslip towards the sample and cover it fully.

    • Care to be taken to prevent the formation of air bubbles under the cover slip.

  6. Blot around the slide to remove excess stain using tissue paper. Secure the coverslip with transparent tape.
    • Blot around the slide to remove excess stain using tissue paper.

    • Secure the coverslip with transparent tape.

    • Do not press on the tape as there are chances of it leaving marks.

    • Ensure that your hands are clean when you touch the cover slip.

  7. Place the slide close to the microscope and view towards light. Observe the onion cells using the 4.5 mm bead  microscope. Observe the onion cells using the 4.5 mm bead  microscope.
    • Place the slide close to the microscope and view towards light.

    • Observe the onion cells using the 4.5 mm bead microscope.

  8. Place the slide close to the microscope and view towards light. Observe the onion cells using the 2.5 mm bead microscope. Observe the onion cells using the 2.5 mm bead microscope.
    • Place the slide close to the microscope and view towards light.

    • Observe the onion cells using the 2.5 mm bead microscope.

    • Blur image - Clean glass slide and cover slip with tissue paper.

    • Blur image with air bubbles - Remove excess water

    • Shrunken image - Do not dry the sample.

    • Cover slip is floating - Blot out the excess stain.

  9. Viewing the epithelial cells of Garlic. Use Iodine as stain (instead of safranin).
    • Viewing the epithelial cells of Garlic.

    • Use Iodine as stain (instead of safranin).

    • Click on the Variations Guide to try these!

Finish Line

Suhail Ahanger

Member since: 05/02/2017

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