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Science Rocks!

Cauldron Bubbles


your results

Sent in by:
Margaret of Jackson, NJ

Mix up a bubbly brew.

Materials Needed

  • clear glasses
  • water
  • oil
  • salt
  • sugar
  • sand



  1. Check with an adult before you begin.
  2. In the ZOOMscis, Dancing Raisins and Dancing Raisins II, you can make different objects fall and rise in water. You can do this with bubbles of oil too!
  3. Fill a glass half full of water.
  4. Add about a half-inch of oil. The oil will float on top because it is less dense than the water.
  5. Pour in some salt. What do you see?
  6. When you pour in the salt, it brings a bubble of oil down with it. The salt and the oil together are more dense than the water, so they sink. When the salt dissolves in the water, the oil floats back to the top because now it is less dense than the water.
  7. See if you can make cauldron bubbles with different materials. The ZOOMers tried sugar and sand.
  8. Make predictions about what you think will happen with each different material.
  9. Record your results and send your discoveries to ZOOM!

What happens if you make Cauldron Bubbles using hot water? How about if you use very small amounts of salt? In the ZOOMsci, What's More Dense?, you can compare the density of different liquids. Can you make Cauldron Bubbles with liquids other than oil and water? Think of one variable to test, make some predictions and share your results with the ZOOMsci-entific community.

Some of your Results

Vittle, age 8 of Sacramento, CA wrote:
We added lots of baking products. salt, baking soda, epsom salt, corn meal, corn starch (didnt sink). It was really cool.. especially the salt and sugar

King Vang, age 14 of Milwaukee, WI wrote:
The bubbles floated, it was so cool!

King, age 11 of Milwaukee, WI wrote:
Bubbles floated up like a lava lamp!

Denise, Colin, and Jeremy of Apex, NC wrote:
we used a lot of different things. Glue was pretty cool. Some strings took a while to sink. A piece of bread (tiny chunk) floated for a while, then sank and expanded like a sponge. Then we rolled up a small chunk of bread and watched it sink immediately. Lots of other items were cool- like the pepper someone suggested.

Sarah of Hecker, IL wrote:
I added pepper... Had to push on it make it go down, but it was really cool once it did. Since pepper is less dense than the water, once the oil sank with it, it came back up in chunks with the oil.

Alex, age 8 of Helper, UT wrote:
Well when I trided it, IT WORK!!!

Jayden, age 8 of Kansas City, MO wrote:
The bubbles rose & blew up. We thought we could use it as a lava lamp. It was so cool!

Emily, age 11 of Greenwood, IN wrote:
they gave us water sugar oil salt vingar. the salt and the surgar went to the buttom and the vingar went to the top!

Catherine, age 10 of Braintree, MA wrote:
i did this befor but you could use food coloring it actioly worked and this 1 of the things I have to do for a summer packet

Hannah, age 11 of Manchester, MA wrote:
When I did this experiment, the bubbles looked sooo cool! We thought it could be a lava lamp!

Monica, age 8 of Baltimore, MD wrote:
I used sand with one glass of water. Some of the sand sank to the bottom and some stayed at the top. In another glass I used oil. This made bubbles at the top of the glass and they merged together to form one big bubble at the end.

Serena, age 9 of Port Charlotte, FL wrote:
Filled glass of water with 1/2" of oil resting on top of the water. And we added salt to the glass. When the salt hit the oil, bubbles formed and fell to the bottom of the glass. After about 12 ceconds the oil separated from the level where the oil was. Also, some of the salt dissolved in the water and the water got cloudy. Nextwe dropped sugar in the water and bubbles fomed, fell to the bottom of the glass and than rose back the oil level. Finally we added sand to the water glass. When the sand was hit the oil stuck to the sand, bubbles formed and the bubbles did not separate from the sand. What we figured out was that the oil sticks to the sand more than it sticks to the salt of sugar.

Ayanna, age 12 of Houston, TX wrote:
the sand and the oil. the sand went to the bottom because of density in cold water it went down slow/ but in hot water it went down fast!! and the oil just stayed at the top or on top of the water. sugar and oil. the sugar and oil are just like the sand and oil/the sugar was slower in cold water that hot.

Eva, age 5 of Omaha, NE wrote:
when you put soy milk and vinegar with the other ingredients and food coloring it`s awesome.

Tamin, age 10 of New York City, NY wrote:
the bubbles looked like the ones in the the lava lamps. also when you put in coloring. It was awesome

Starr, age 9 of Lubbock, TX wrote:
well at first we had to wait then, it started to bubble like crazy!!!

Cassidy, age 10 of Wynantskill, NY wrote:
it bubbled up when I put salt in the cup of water!

Nusrat, age 10 of New York wrote:
there was bubbles all over my bathtub!!!

Anna of IL wrote:
When I put salt in it only a few bubbles came up. Then it stopped.

Shelby, age 10 of Perth, WA wrote:
It worked great but I found if you put more oil it works better!

Domokito, age 6 of Saint Louis, MO wrote:
it fizzed and had reactions. I used baking powder and water.

Tori, age 12 of Suwanee, GA wrote:
I had loads of bubbles come up when I poured in the salt.

Vithiya, age 14 of Malaysia wrote:
I use some food colouring in it and it was awesome! The teachers were really attracted by this experiment!

Alayzia, age 10 of Mount Vernon, NY wrote:
it bubbled everywhere.

Marcus of Lauderdale Lakes, FL wrote:
The experiment looked like lava.

Faith of Schweinfurt, Germany wrote:
The bubbles went up and down, just lide a lava lamp! It was so cool!

Christa, age 11 of Saint Croix wrote:
i used it and it was cool! I added blue color and it looked like a lava lamp.

Savannah, age 11 of Dothan, AL wrote:
I saw the bubbles in the experiment and it really works!

Indira, age 14 of Malaysia wrote:
it was cool! it make more bubbles. I try it wif food colouring, and my bubbles were colourful!

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