Homemade Lava Lamps

I loved those fancy lava lamps when I was a kid, but alas, my parents did not buy one for me.  Here’s a DIY Homemade Lava Lamp with some science sneaked in!  Super easy and mesmerizing for the superheroes in your life!

Here’s what you need to get started:

  • Empty water bottle (or any clear bottle)
  • vegetable oil (any light colored oil will do but this is probably the cheapest)
  • Food coloring
  • alka seltzer tablets

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Fill the bottle a little more than halfway with oil.

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Then add water to it until it’s about an inch or two from the top of the bottle.

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Add about 5-10 drops of food coloring. Watch how the color drips down through the oil to the water.

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Break one of the alka seltzer tablets into 4-5 pieces.  Use caution with young children who might be tempted to put this in their mouths!  It is a cold medication and should not be ingested by children!  IMG_1984

Add one piece to the bottle and watch the magic begin!

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Once the alka seltzer tablet has completely dissolved, add another one and watch the colored bubbles rise and sink again!  Repeat as many times as you’d like!  You can even try adding some glitter for some extra fun!

The Science behind the Activity:

Water and oil are insoluble, they do not mix.  Water is denser than oil and stays as a separate layer at the bottom of the bottle.  Food coloring is soluble in water so it colors the water but not the oil.  When the alka seltzer is added, it forms gas bubbles that rise to the top, “dragging” the colored water along with it.  As the water reaches the top and the gas bubbles pop near the surface of the oil, the denser water falls back down through the oil.  The process keeps repeating itself until the alka seltzer has completely dissolved an no longer forms any bubbles.

This activity can be done with adding salt instead of alka seltzer (for those of you who are concerned about using medication with kids) but the results are not as good and eventually the salt saturates the water and makes it cloudy.  Let me know if you try it with some other fizzy tablets such as Airborne.  Curious to see if those work just as well.

Follow this link to see where I got the idea from and more details about the experiment: http://slsmithphotography.typepad.com/my_weblog/2010/06/lava-lamps-summer-fun.html

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