Foldscope In The Classroom: All About Me!

Question:

Who am I and what am I made of?

Science is about learning how things work. And what better way to learn than through a scientific deep dive into your own self? Read on for a fun way to let your students discover the microscopic secrets hidden within themselves with a Foldscope 2.0!

Figure 1. Picture of a fingerprint viewed under a Foldscope 2.0 at 50X magnification using brightfield (left) and dark field (middle and right) lighting.

All fingerprints have distinctive characteristics to them including loops, whorls, and arches. No two people have the same fingerprints, not even identical twins!

(Photo Credit: Holly A. Stuart)

Background:

The beginning of the school year is usually a time for “getting to know you” activities, lab safety information, and an introduction to the course content. If you are going to be using microscopes during the year, this is a great time to bring out a classroom set of Foldscopes and let students practice their microscopy skills while using their favorite subject - themselves!

Figure 2. Picture of cheek cells viewed under a Foldscope 2.0.

Cheek cells are skin cells that are flat and have a distinct nucleus visible inside the cell. The cell membrane and nucleus can be made more noticeable by using stains.

(Photo Credit: Holly A. Stuart)

Materials/Procedure:

The materials here are suggestions for collecting samples. Feel free to make adjustments to suit the needs of your students. For safety purposes, it is best to use only samples that can be obtained without breaking the skin.

Materials:

Science notebook
Pen/pencil
Classroom set ofFoldscope 2.0s
Blank Trading Cards
Ring Stickers
Clear Stickers
Lens Kit
2.0 LED Light Module Kit
Tweezers
Toothpicks
Pipettes
Methylene Blue Stain (optional)
Hot Glue Gun (optional)
Inkpad (optional)

Figure 3. Picture of sweat (liquid (top) and evaporated (bottom)) viewed under a Foldscope 2.0 at 140X magnification plus 5X zoom on my phone.

Sweat is composed of water, salt, and amino acids. The body produces sweat to cool down. The above liquid images show droplets of oil mixed in with the sweat.

(Photo Credit: Holly A. Stuart)

Procedure:

Think through the samples you want your students to collect (hair, eyelashes, cheek swabs, teeth scrapings, tears, sweat, skin (think hangnails, chapped lips), fingernail clippings, fingerprints, etc.).
Have students prepare slides of each of the samples.

Dry Mount: for hair, skin, and fingernails

Prepare the blank trading card with a clear sticker on the back. (See this video if you have questions about how to use the trading cards.)
Place the sample on the front and seal it in with another clear sticker.

Wet Mount: for tears and sweat

Prepare the blank trading cards with a clear sticker on the back.
Place a ring sticker on the front and remove the clear sticker cover slip.
Add a drop of liquid (tears/sweat), let the sample evaporate in a sunny spot, and then replace the clear sticker cover slip.

Smear: for cheek swab and teeth scrapings

Prepare the blank trading cards with a clear sticker on the back.
Cheek Cells: Gently rub the toothpick on the inside of your cheek, smear the cells onto the front of the trading card, and seal them in with another clear sticker. (Optional - add methylene blue stain to more clearly view the nucleus and cell membrane.)
Teeth Scraping: Gently scrape the toothpick along the surface of your teeth, spread the scrapings on the front of the trading card, and seal them in with another clear sticker.

Fingerprints: (optional)

Prepare the blank trading card with a clear sticker on the back.
Place a small thin layer of hot glue on the front of the card (give it a few seconds to become warm, not hot).
Place a finger on the inkpad and then gently roll the finger through thewarm glue leaving an imprint of the finger.
Let the glue dry completely and seal it in with another clear sticker.
Note: there are variations for how this can be completed if you are not comfortable with using a hot glue gun in your classroom. For example, have your students spread a VERY thin layer of white glue on their finger, let it dry and then gently peel it off and place it on a trading card. Make sure students understand that they do not need much glue at all (it only needs to be as big as the hole on the trading card).

View the samples by placing the trading cards into the Foldscope one at a time and using the focus ramp to adjust the clarity of the images.

Use the LED light module and experiment with the different lighting techniques to discover how changing the angle at which light hits the sample can significantly change the microscopic image.
Use the different lenses to change the magnification from 50X to 140X to 340X to determine which gives the best microscopic view of the samples.

Have students:

draw and label what they see in a science notebook,
couple their phones or tablets to the Foldscope to take pictures of the magnified samples.

Figure 4. Picture of a hangnail viewed under a Foldscope 2.0 at 140X magnification.

The top layer of the skin is called the epidermis. This layer is made of dead skin cells that get shed on a regular basis. The above pictures show dried skin cells that look more like rocks than soft pliable skin!

(Photo Credit: Holly A. Stuart)

When your students have finished observing and documenting their samples, have them reflect on how this microscopic view of themselves changed their perspective on “who” and “what” they are.

Figure 5. Picture of an eyelash viewed under a Foldscope 2.0 at 140X magnification.

Eyelashes are specialized hairs that line the top and bottom of the eyelid and protect it from dust and other debris. The pictures above show the medulla (the dark pigment that runs through the core of the lash) and the root.

(Photo Credit: Holly A. Stuart)

Extension:

This blog ties together the three dimensional framework of the NGSS. It covers the Disciplinary Core Idea of Life Science. Students will see the Crosscutting Concept of Structure and Function. This activity is also a way for students to deepen their understanding of the Science and Engineering Practice of Obtain, Evaluate, and Communicate Information.

However, this exploratory activity can go beyond the science classroom. Join forces with:

a Social Studies teacher to zoom out from the microscopic view and take a comparative large scale view of cultures around the world,
a Math teacher to create graphical representations of the different physical characteristics discovered during the activity,
an ELA teacher to write personal narratives that describe how the students see themselves from a microscopic perspective,
and a related arts teacher to create a personalized multi media display of the microscopic images!

Figure 6. Picture of hair viewed under a Foldscope 2.0.

Hair, a structure that is found only on mammals, provides temperature control and skin protection. Forensic scientists use hair for identification purposes by looking for certain physical and biological characteristics. The above pictures show the color of the hair (in this case a mixture of brown and gray) and the scales (the distinctive patterns on the outside of the strand of hair).

(Photo Credit: Holly A. Stuart)

Connect:

Share your observations, discoveries, pictures, and interdisciplinary extension activities with the Foldscope community. Submitting your Foldscope images related to the topic to the Microcosmos will help build up a strong scientific database that can help support new and innovative scientific research! Tag us on social media when you post the results of your explorations, creations, and discoveries! We love to see how Foldscopers around the world are using their Foldscopes in new and innovative ways!

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Sources:

https://www.forensicsciencesimplified.org/prints/principles.html

https://www.britannica.com/science/perspiration

https://humanbodylearning.com/fun-skin-facts-kids-science/

https://www.news-medical.net/life-sciences/Hair-Analysis-in-Forensic-Science.aspx