Let’s make a Lava LampBy: Loudoun Science Pals

About Loudoun Science BuddiesMercer Middle School ClubTeam members: Minna Kuriakose and

Madeline Luberecki

Science is our passion

Experiment

Today’s experiment is a fun one. Today we will make a homemade lava lamp.

Materials

•Clear 16 ounce plastic water bottle •Vegetable oil•Water•Food coloring •Alka-Seltzer tablets•Sharpie

http://www.wired.com/geekdad/2007/07/alka-seltzer-ta/

Procedure• Make a mark with the sharpie at about ¾ of the bottle• Fill the bottle with an inch of water• Pour vegetable oil into the bottle till you reach the mark. • Wait for the vegetable oil and the water to separate in the

bottle• Pour 10 drops of food coloring, more or less depending on

what you like• Wait for the food coloring to fall and mix with the water.• Once the food coloring is well mixed, take an Alka-Seltzer

and break it in half.• Drop the Alka-Seltzer into the bottle and watch the lava

lamp come alive.• For more special effects, place the bottle on top of a

flashlight in a dark room and drop the Alka-Seltzer

What’s the Science behind this?

Density and Intermolecular

Polarity

What is density?

•relative “compactness” of objects with a constant volumeDensity of water: 1,000 kg/m³

Density of Olive oil: 918 kg/m3

How does it work?

•Since the oil is less dense than the water, the oil sits on top of the water. When it is dropped into the oil, the food coloring falls to the bottom with the water. The food coloring (water based) and the water do bond together, so they mix well.

Why don’t oil and water mix? (Intermolecular Polarity)•Water molecules have a slight positive

charge on the hydrogen and a slight negative on the oxygen. This makes water a "polar" liquid.

Why don’t oil and water mix?

•Oil particles are made of chains of carbon atoms bonded to hydrogen. The elements and structure of oils make them non-polar.

Because water molecules are polar and oil particles are non-polar, the water and the oil don’t mix.

What next?

•When the Alka-Seltzer is dropped it reacts with the water. It creates gas bubbles which rise to the top of the bottle carrying the water with it. This is why you see the bubbles.

Reflection Questions

•Does the temperature of the water affect the reaction? 2. Does the size of the bottle affect how many blobs are produced?3. Does the effect still work if the cap is put on the bottle?4. Does the size of the tablet pieces affect the number of blobs created?

Citation• Any picture that is not cited has come from

clipart• http://www.wired.com/geekdad/2007/07/alka-s

eltzer-ta

• http://chemstine.com/Lessons-and-Homework7.php

• http://www.ujnews.com/happy-birthday-lava-lamps/

• http://www.spencersonline.com/product/lava-lamp-with-purple-lava-yellow-liquid-and-silver-base/

• http://serc.carleton.edu/mathyouneed/density/index.html