"If you can't make a mistake, you can't make anything." - Marva Collins
Here is a simple, fun experiment that children can enjoy doing at home. Lava lamps are mesmerizing to watch -- but did you know you could make your own? By utilizing the properties of polarity, you can create your own lava lamp through these steps:
Materials:
Empty bottle
Vegetable oil
Water
Food coloring
Alka-seltzer
Instructions:
Fill the bottle most of the way with vegetable oil. (up to the 3rd notch on the sides of the water bottle)
Fill the rest of the bottle with water. (up to the last notch on the water bottle). The water will sink to the bottom under the oil.
MAKE SURE YOU DON'T FILL IT UP COMPLETELY!
Add a few drops of food coloring (choice of color). The food coloring is water-based, so it will also sink and color the water that is now at the bottom of the flask.
Break an alka-seltzer tablet into a few small pieces, and drop them in the bottle one at a time.
Watch your lava lamp erupt! As the reaction slows down, simply add more alka-seltzer to continue the reaction.
MAKE SURE TO NOT HAVE THE BOTTLE CAPPED OR THE BOTTLE WILL EXPLODE.
Science Behind It:
Density: measurement of how compact a substance is or how much of it fits in a certain amount of space.
Scientific equation is density = mass/volume.
In the experiment, water is more dense than the oil, so that is why it sinks to the bottom. Same with the food coloring, because it is water-based. Water molecules are packed more tightly and a cup of water actually has more mass than a cup of oil.
Density is also affected by temperature. The hotter a liquid is, the less dense it will be.
Water and oil don’t mix because they have different polarities.
Water molecules are "polar" because they have a lopsided electrical charge that attracts other atoms. The end of the molecule with the two hydrogen atoms is positively charged. The other end, with the oxygen, is negatively charged. Just like in a magnet, where north poles are attracted to south poles ("opposites attract"), the positive end of the water molecule will connect with the negative end of other molecules.
Oil molecules are non-polar, meaning they don't have a positive or negative charge, so they are not attracted to the water molecules at all.
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