Extreme Science: Penny Shine

What you will need:

  • Clear drinking glass
  • Water
  • Vegetable oil
  • Food coloring
  • Alka Seltzer ® tablets
  • Adult supervision


  1. Fill your glass about ¼ of the way full of water.
  2. Add a few drops of food coloring and mix thoroughly.
  3. Slowly pour in your vegetable oil to fill your glass until it is about one inch from the top.
  4. Once the oil and water separate and settle down, drop in one half of an Alka Seltzer tablet.

What is going on?

Oil and water do not mix.  If you remember when we did our density column, the oil will float on top of the water since the oil is less dense then the water.  When you drop your Alka Seltzer tablet in the glass, it will sink all the way to the bottom.  When the Alka Seltzer tablet begins to dissolve and create gas bubbles, these bubble will float to the top of both the oil and water.  As it dissolves in the water, tiny colored water droplets will get caught up in with the gas bubbles causing it to float to the top.  Once they reach the top, the gas bubbles will pop, releasing the gas causing the water droplets to again sink to the bottom since the water is more dense than the oil.

Radical Rick

Extreme Science



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