Sharpie Pen Science Experiment


  1. Drape the cotton cloth over the opening of the cup.
  2. Secure the cloth to the cup with the rubber band. Pull the cloth down on all sides so it is smooth and taut across the surface of the cup opening.
  3. Pour the isopropyl alcohol into the dropper bottle so that it is 2/3 full.
  4. Use the pens to make small color designs on the cloth over the cup opening. Keep it simple at first – geometric shapes, dots, lines, wavy lines, 2 or 3 colors, etc. – but expand to more interesting designs as you get more practice. The secret is to keep your designs small and always over the middle of the cup. Enjoy! It can be a very beautiful result.
  5. Slowly drop 15 -20 drops of isopropyl alcohol in the center of the design and watch it for a few minutes. Don’t flood a design. After some experience, you’ll find that placing drops in various locations at once will result in some very interesting and colorful designs. It is better to use less than to overdo the isopropyl alcohol. When you have what you want, let the design dry for 3-5 minutes. Move on to another location and have at it! Keep the design within the rim of the cup.
  6. Heat-set your designs by running them in a clothes dryer on normal setting for about 15 minutes. Wear your designs proudly and don’t worry about anyone who calls you a “hippie.” They’re way older than you are anyway.

Materials List

  • Large-mouth plastic cup 
  • Rubber band 
  • Isopropyl alcohol 
  • Sharpie® pens, various colors 
  • Piece of white cotton fabric 
  • Dropper squeeze bottle 
  • Adult supervision

How Does It Work?

This is really a lesson in the concepts of solubility, color pigment mixing, and the movement of molecules. Remember that you’re dealing colors of pigments and not colors of light. Sharpie® markers contain permanent ink which will not wash away with water. Permanent ink is hydrophobic, meaning it is not soluble in water. However, the molecules of the ink are soluble in rubbing alcohol. As it spreads out in an even, circular pattern from the center of the application, the alcohol carries the various pigments of ink with it and “drops” them off at specific locations from the center depending on their unique solubility. You’ll be very surprised at the colors that flow from just black ink. Colors are found in the most interesting places!

Take it Further!

Now that you are an expert at making these cool designs, try making your own colorful t-shirt! Go find a plain white 100% cotton shirt or an old shirt from your closet and make a fun sharpie design shirt that your friends will go crazy for. Just remember that whatever you use needs to be 100% cotton for the color to spread properly.

With all the different kinds of Sharpie pens available at the store, try using different colors. You may find that some of the neon colors even glow under black light. This will for sure take your designs to the next level!

Additional Information

Remember that Sharpie markers are permanent. Be careful not to get them on your other clothes as you will not be able to remove the color.

Science Fair Connection

Creating these Sharpie pen designs is pretty cool, but it isn’t a science fair project. You can create a science fair project by identifying a variable, or something that changes, in this experiment. Let’s take a look at some of the variable options that might work:

      • Use different kinds of fabric. Which works better? 100% cotton, or a fabric that doesn’t have cotton in it?
      • Try using different percentages of Isopropyl alcohol. Does 91% work better or worse than 70%? Is there another liquid that works better than Isopropyl alcohol?

That’s just a couple of ideas, but you aren’t limited to those! Try coming up with different ideas of variables and give them a try. Remember, you can only change one thing at a time. If you are testing different liquids, make sure that the other factors are remaining the same!