1 Create Your Own Lava Lamps

JESSICA LOGAN / BRANCH MANAGER

Hamilton Mill Branch, Gwinnett County Public Library

Type of Library Best Suited for: School or Public

Cost Estimate: Under $50

Makerspace Necessary? No

PROJECT DESCRIPTION

Create your own lava lamp using basic household items like recycled plastic bottles, vegetable oil, food coloring, and fizzy tablets. Have a blast from the past with these colorful, take-home projects that are sure to result in a hit maker program.

This program is a one-hour stand-alone event that can easily be held at any time during the year. The Gwinnett County Public Library hosts this event with a target audience of teens and tweens in grades 6–12, but this project is also suitable for a younger age group. Even before adding the fizzy tablets, children enjoy watching their creations bubble and swirl inside the plastic bottles.

OVERVIEW

Aimed at teens and tweens in grades 6–12, the participants work to create lava lamps using basic household items, including plastic bottles (20-ounce beverage bottles work especially well), vegetable oil, food coloring, and fizzy tablets. Because many of the participants become excited at the prospect of creating their own lava lamp, be sure to provide step-by-step written instructions for the activity prior to beginning so that they can be used as a reference. Before and throughout the activity, explain not only what steps to take, but also the science behind each one.

We do not limit this program to a specific number of participants, but we do make sure to have enough materials on hand so that everyone can take home a lava lamp. Start collecting bottles early so that you have enough. You can always use smaller bottles if you have a limited budget to purchase the other materials, or end up needing to stretch your vegetable oil a little more than planned.

MATERIALS LIST

◦ Clear, empty, and clean plastic bottles (20-ounce ones work great)
◦ Food coloring
◦ Water
◦ Vegetable oil
◦ Alka-Seltzer tablets (or other tablets that fizz)
◦ Tablecloths

NECESSARY EQUIPMENT

◦ Funnels
◦ Water pitcher
◦ Tables
◦ Flashlight (optional)
◦ Camera or other device to take pictures (optional)

STEP-BY-STEP INSTRUCTIONS

Prior to the start of the event, make sure to cover any tables to be used during the project with a tablecloth for easy cleanup. The plastic, disposable variety of tablecloths are an inexpensive option that works well for this purpose.

Throughout the program, be sure to explain both the steps and the science behind the project. For example, oil and water do not mix very well. The water and oil separate from each other and the oil ends up on top of the water because it has a lower density. The piece of an Alka-Seltzer tablet that you drop in the bottles fizzes and releases small bubbles of carbon dioxide gas that rise to the top of the bottle. Some of the colored water is taken with the gas up to the top of the bottle as well. The gas escapes when it reaches the top and the colored water comes back down. The reason Alka-Seltzer fizzes in such a way is because it contains citric acid and baking soda (sodium bicarbonate): the two react with water to form sodium citrate and carbon dioxide gas (those are the bubbles that carry the colored water to the top of the bottle).

Once the participants have had an opportunity to read over the instructions and ask any related questions, you may distribute the needed materials. If we have been able to collect bottles of various shapes and sizes, we allow the participants to choose which one they would prefer. Because food coloring is an inexpensive material, we also make sure to have several different colors available for the students to personalize their lava lamps with.

To begin creation of the lava lamps, pour water into the plastic bottle until it is approximately one quarter full. You may wish to use a funnel when pouring to avoid spills. Next pour in vegetable oil until the bottle is nearly full. Wait (patiently, if possible) until the oil and water have separated . . . this step should not take too long. Add about a dozen drops of the chosen food coloring to the contents of the bottle. Have the participants observe as the food coloring falls through the layer of oil and mixes with the water. Finally, break your Alka-Seltzer tablets into pieces (about 4–5 pieces per tablet will do) and drop one piece into the bottle. The contents of the bottle should immediately begin fizzing and bubbling around like a real lava lamp. In our experience the children are always enthralled with this process, so it is a good idea to try having enough Alka-Seltzer pieces so that each participant can make their lava lamp come alive several times. You can also use this as an opportunity to reiterate that the reason the Alka-Seltzer fizzes in such a way is because it contains citric acid and baking soda (sodium bicarbonate): the two react with the water to form sodium citrate and carbon dioxide gas, which are the bubbles that carry the colored water to the top of the bottle. If you opted to provide a flashlight for the event, you can now shine it through the bottom of the bottle to give the contents more of a glowing lava lamp effect as it bubbles . . . this also makes for an excellent photo opportunity!

When the bubbling stops, you can always add another tablet piece and watch the fun reactions begin again. We allow our participants to take their groovy creations with them to enjoy (with the addition of more Alka-Seltzer tablets) at home.

LEARNING OUTCOMES

◦ Learn about molecular reactions and liquid density.
◦ Observe chemical reactions as the ingredients are combined to create a truly uplifting experience.

RECOMMENDED NEXT PROJECTS

This maker project has been a huge success at our branch each time it has been hosted, and several of the other branches within the Gwinnett County Public Library system have adapted it for their own use as well. The students always have a blast and we find that the materials are fairly inexpensive . . . or even free, in the case of our collection of recycled plastic bottles. If you have leftover bottles, you may consider trying a “Tornado in a Bottle” program to use up the remaining materials and to give your library users a new experience with a similar feel.

Feeling brave? If you have a place, such as a suitable outdoor area, you might also think about having your participants learn about chemical reactions on a larger, more explosive scale by trying out a Diet Coke and Mentos eruption. We have not tried this one ourselves, but I can only imagine the lasting impression it would make.