7th Grade Lab Preview: Preparing Microscope Slides

March 2015

The topic for this month’s lab is preparing plant and animal cells through a process known as wet mounting. Wet mounts are done to enhance viewing by increasing translucency (the quality of allowing light to pass through) and sometimes to help flatten the specimen for better viewing.

What samples will we be studying?

  • Elodea (plant cells): Elodeaare a genus of aquatic plants often called “waterweeds”. Elodea are multi-branched perennial plants that can survive both as rooted plants or free floating fragments. They are common in household aquariums and can be easily obtained from your local pet store.
  • Human Cheek Cells (animal cells): We will need several volunteers to offer up their cells for science this week! Cheek cells can be easily and painlessly obtained by gently scraping the inner cheek with a flat-sided toothpick.

Making the slides

You will be working in pairs this week to prepare your slides. Each lab partner will prepare one of the specimen slides. The specimen slides will be made during class by observing the wet mount technique that is demonstrated by your teacher. This technique can be challenging to master, so it’s importantto pay close attention during the demonstration, to be patient, and to try your best. Much like last month, a significant portion of your grade will be based on your performance in the lab. Each partner will need to do their part to earn the maximum number of allotted performance points.

Please exercise caution when handling the slides and cover slips. The glass is thin and can easily shatter and impale your skin.

Using the Microscopes

Being that it’s been a month since you used the microscopes, it would be beneficial to review the MICROSCOPE SAFE HANDLING RULES you received last month. You do not want to waste precious lab time trying to recall how to focus the microscopes.

You will NEED the following items for this lab:

  • Safety goggles (MUSTbe on prior to entering the lab and will be worn for making the slides. Goggles may be removed when looking through the microscopes.)
  • Pencil and eraser
  • Long hair MUST be secured into a bun prior to entering the lab.
  • Colored pencils/pens (Please bring them, if you have them.)

You will NOT need the following items:

  • Food or drinks (including gum/mints and bottled water)
  • Loose fitting jackets/sweaters
  • Extra books, bags/purses, etc. EVERYTHING MUST FIT INTO YOUR BACKPACK. PLEASE PLACE ZIPPERED BACKPACKS ON THE BACK OF YOUR CHAIR.

References