Glow in the Dark Egg Experiment – Osmosis
Glow-in-the-Dark Egg Experiment: A Science Project That Will Light Up Your Learning!
There’s nothing quite like seeing your students’ faces light up (literally!) when science gets messy and fun. If you’re looking for a hands-on activity that feels like pure magic and sneaks in some great science lessons, the Glow-in-the-Dark Egg Experiment is a must-try.
Materials and Instructions for the Glow-in-the-Dark Egg Experiment
Gather the following items:
- Raw egg
- Cup
- Vinegar
- Highlighter ink
- UV light
Procedures:
- Carefully place the raw egg into the cup.
- Completely cover the egg with vinegar.
- Carefully remove the end of the highlighter with scissors. Remove the inside highlighter tube.
- Squeeze the highlighter liquid into the cup.
- Let the egg sit in the vinegar and highlighter liquid for 48 hours.
- After 48 hours, carefully rinse any remaining shell off the egg.
- Take the egg into a dark area, shine the UV light on the egg, and watch it glow!
Glow in the Dark Egg Experiment in Video and Photos
Download the Printable Lesson and Worksheets
What is Happening in the Glow-in-the-Dark Egg Experiment
Vinegar contains acetic acid. When you put the egg into vinegar, a chemical reaction happens between the acetic acid in the vinegar and the eggshell made of calcium carbonate. During this reaction, carbon dioxide is created. How do you know carbon dioxide is present? You can see the carbon dioxide bubbles!
As the acetic acid interacts with the calcium carbonate, it dissolves the shell, leaving behind just the soft, flexible membrane of the egg. Looking closely during the first few hours, you’ll notice tiny carbon dioxide bubbles forming all over the egg — that’s the chemical reaction.
When acetic acid and calcium carbonate mix, they react and create calcium acetate, water, and carbon dioxide.
Older students can write what’s happening using this chemical equation:
2 CH3COOH + CaCO3 = Ca(CH3COO)2 + H2O + CO2
Or the reaction looks like this:
Acetic acid (vinegar) + calcium carbonate (eggshell) → Calcium acetate + Water + Carbon dioxide gas
Once the shell is gone, something even cooler happens. The egg ‘s membrane is semi-permeable, letting certain small molecules pass through, like water and small dye particles. Through osmosis, water from the vinegar mixture (along with the fluorescent dye from the highlighter) moves into the egg.
Did you notice that the egg looked bigger once the shell dissolved? If you checked the label on the vinegar bottle, you might remember that vinegar is made up of both acetic acid and water.
The water in the vinegar and fluoescent dye from the highlighter moved through the egg’s soft, semi-permeable membrane and flowed into the egg. This movement happens because of a process called osmosis.
Osmosis is when water naturally moves from an area where there’s a lot of water (high concentration) to an area where there’s less water (low concentration). No energy is needed for this to happen — it’s a type of passive transport.
This causes the egg to swell and soak up some glowing ink. When we shine a black light on it, all that fluorescent dye trapped inside the egg lights up!
I hold a master’s degree in child development and early education and am working on a post-baccalaureate in biology. I spent 15 years working for a biotechnology company developing IT systems in DNA testing laboratories across the US. I taught K4 in a private school, homeschooled my children, and have taught on the mission field in southern Asia. For 4 years, I served on our state’s FIRST Lego League tournament Board and served as the Judging Director. I own thehomeschoolscientist and also write a regular science column for Homeschooling Today Magazine. You’ll also find my writings on the CTCMath blog. Through this site, I have authored over 50 math and science resources.