Blobs In A Bottle

How Does The Size of The Tablet Affect The Amount of Blobs?

Our Hypothesis

If we put a full Alka Seltzer tablet in the bottle then there will be more blobs.


  • A clean .5 liter soda bottle
  • 3/8 cup of water
  • Vegetable oil
  • Fizzing tablets (such as Alka Seltzer)
  • Food coloring


  1. Pour the water into the bottle.
  2. Use a measuring cup or funnel to slowly pour the vegetable oil into the bottle until it's almost full. You may have to wait a few minutes for the oil and water to separate.
  3. Add 10 drops of food coloring to the bottle. The drops will pass through the oil and then mix with the water below.
  4. Break the Seltzer tablet to the size desired and drop it into the bottle. Watch it sink to the bottom and let the blobby greatness begin!
  5. To keep the effect going just add another tablet piece. For a true lava lamp effect, shine a flashlight through the bottom of the bottle.

Testing Alka Seltzer Tablet Size

Trial 1: We used a small tablet which created little blobs that moved straight up and then straight down.

Trial 2: We used half of a tablet which created a larger amount of blobs and the blobs were bigger.

Trial 3: We used a full- sized tablet which created giant blobs but not as many.


Our conclusion is that the medium sized tablet works best for making the best blobs! Our hypothesis was not correct. We didn't use the small sized tablet because we wanted to make sure that blobs are not small enough where you can't see them but are at the size where they are greatly visible. We didn't choose the bigger tablet because it didn't show a lot of blobs and they didn't stay in the vegetable oil very long.

By: Caitlyn Pearson and Alyah Craig

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