Germs, black light, and slime, oh my!

How are germs transferred among people? What are good methods to remove germs from your hands? These are the questions we will ask the children to answer during this fun, glow-in-the-dark activity.

While we’ve got the black light out, let’s add another activity to teach about polymer science. The children will mix two solutions together to make slime that is fun to play with and with the right additions, can glow in black light. This activity includes concepts of light (electromagnetic radiation), health, and polymer chemistry, but you know, sometimes science and real life are messy that way!

Safety note: Be sure to explain safety precautions to children. This experiment uses chemicals and the room will be dark. Eye protection should be used. Measuring devices should not be mixed between substances. Avoid getting chemicals on clothing. After these experiments, be sure to thoroughly clean hands. Disclaimer: All information provided on this site is for entertainment purposes only. Using any information from casabouquet.com is at your own risk.

Instructions

Part I germs for kids and cleaning

• Begin by asking how bacteria and viruses (germs) get passed between people. (Hands, mouth, surfaces, etc.). Discuss how you wash your hands correctly and use hand sanitizer. You may have to do some research here!
  •  Glo germ lotion was developed to help hospital staff check on their cleaning effectiveness. The lotion has particles that react to black light that are 5 microns in size, similar to microbes. This odorless lotion is non-toxic and will wash off.
•  Provide a quarter-size dollop of lotion to each child and ask them to rub thoroughly into their hands. Use a paper towel if the lotion doesn’t completely dry.
•  Time to teach a lesson. This would be a good time to talk about germs, disease, and hand washing or the electromagnetic spectrum and visible and ultraviolet light.
• Darken the room and turn on the black light. You may want to keep a regular flashlight handy for safety’s sake. Shine the light on the children’s hands and face and anything they may have been touching while you were teaching. Turn the lights back on and ask them to record their observations. This is a great time for a discussion on the spread of germs.
• Divide the children in groups. Each group will try to remove the “germs” with a different method. Suggest longer vs. shorter time washing, using soap vs. not using soap, using hand sanitizer, or using sanitizing wipes.
• Once students have cleaned their hands, have them inspect their hands under the black light to see the effects of washing their hands. Make sure they check around the nails and between the fingers to see if any “germs” are still present. Which was the most effective method? Why was it the best?

Part II making slime

• Start with a demonstration. With a handful of paper clips, show how they easily move around as you pass them hand to hand. This is similar to the polyvinyl alcohol solution’s molecules. Next, hook seven or more paperclips together into chains. This makes a difference in how the paperclips move. This is similar to the reaction that happens when the cross-linking solution, Borax is added.
• Give each child a cup with a lid to use as a shaker.
• Provide 30 ml or 2 tbsp of polyvinyl alcohol and 15 ml or 1tbsp of sodium tetraborate (Borax) into each cup.
• With the lid on tightly, shake the cup until the mixture forms into slime.
• Test the slime under the black light to observe how it glows. Record observations. Make sure children wash their hands after playing with the slime. It can be kept and reused in a tightly sealed cup or plastic storage bag.
• Explain that the slime has been colored with a glow-in-the-dark chemical. UV light from the black light causes the coloring to give off visible light.

Supplies for germs for kids

• Glo-Germ Lotion
• black light
• dark room
• hand-cleaning methods

• 4% solution of polyvinyl alcohol with glow-in-the-dark coloring added
• 4% solution of sodium tetraborate (Borax)
• plastic cups with lids
• paper clips
• paper towels
• paper or notebook for recording results, pen

What is the science?

Content: Assess the impact of products, energy, electromagnetic radiation, light, polymers, microbes, health

The Glo Germ lotion has 5 micron pigmented particles that are sensitive to ultraviolet rays. This is an example of fluorescence. The black light gives off long wave UV or UV-A that is wavelengths between 315 and 400nm. Electrons in the atoms receive energy from the ultraviolet light from the black light and jump to a higher energy level. When they jump back down to their normal level, we see the released energy, or photons, as visible light (lower energy than the UV-A).

The PVA borax slime recipe is a classic polyvinyl alcohol (PVA) formula with sodium tetraborate (Borax) as the cross-linking agent. The Borax solution acts as a cross-linking agent for polymers in the PVA solution and helps the chains connect. The recommended slime kit contains added pigment that is sensitive to ultraviolet rays.

Resource links

• https://www.stevespanglerscience.com/store/atomic-shaker-slime.html
  • Atomic shaker slime from Steve Spangler explains the science and provides a set of 24 shaker cups, bottles of solution, and 2 mini black lights.
• https://www.cmu.edu/gelfand/education/k12-teachers/polymers/polymer-architecture/polyvinyl-alcohol-slime.html
  • More on slime from Carnegie Mellon University
• https://www.mrsec.psu.edu/content/polymers
  • Polymer activity from the Penn State Materials Research Institute
• https://scienceprojectideasforkids.com/fluorescence-vs-phosphorescence/
  • Fluorescence vs. phosphorence from JVC’s Science Fun
• https://www.sciencefriday.com/educational-resources/glowing-in-the-dark/
  • From Science Friday, more fluorescence and phosphorescence activities
• https://science.nasa.gov/ems/01_intro
  • Introduction to the electromagnetic spectrum from NASA
• http://www.cdc.gov/handwashing/
  • Handwashing from the Centers for Disease Control
• http://www.glogerm.com/worksheets.html
  • Educational materials from the Glo Germ company.
• https://www.flinnsci.com/resources/safety-reference/
  • General Lab Safety resources from Flinn Scientific. Be sure to check out the Student Safety Contract.

Let’s talk story

I love how excited children get when you turn out the lights and turn on the black light. Looking at their clothing, or even lipstick, or nail polish under the UV light is fun! These activities have the bonus of testing something they’ve done themselves and being able to discuss the evidence and what they think it means.

I’ll be looking for comments below, or contact me at lisa [at] casabouquet[dot]com.

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