Lava Lamp

Summary

Make your very own lava lamp from household materials!

Materials

• 100 mL of water
• 600 mL of vegetable oil
• Food coloring
• Alka Selzter tablets

Procedure

Perform demonstration in a well ventilated area.

1. Pour water into a beaker
2. Add 3 drops of food coloring
3. Gently pour in the oil
4. When settled, add a tablet of Alka Seltzer
5. Repeat step 4 when bubbling dwindles

Discussion

The scientific principles of density and polarity are what make this lava lamp work. The definition of density is, “the mass of a substance per unit volume” or how much of something can fit into a certain amount of space. When looking at the density of water and oil, water is more dense than oil. This is because the water molecules are more tightly packed together, in turn causing the water to sink to the bottom when added in with the oil in the container. The definition of polarity is, “the particular state either positive or negative with reference to the two poles”. Water molecules are polar because they have partially positive charges on the hydrogen atoms and a partially negative charge on the oxygen atom. Oil molecules are non-polar, meaning they do not have a positive or a negative charge. The oil molecules are not attracted to the water molecules which is why oil and water do not mix. The alka-seltzer drops to the bottom and reacts with the water to produce carbon dioxide bubbles. These bubbles stick to the water droplets and the water/gas combination is less dense than the oil causing the bubbles to rise to the top. Once at the top, the gas bubbles pop and escapes allowing the dense water to sink to the bottom.