🌋 Lava Lamps

Make a bubbling lamp to take home. Draft: not yet checked

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Watch how it is done

Two short videos. Tap one to play it.

Videos play from YouTube, made by other people.

Quick start

Get a pre-filled bottle (about ⅔ oil on top of about ¼ water).
Add 2–3 drops of food coloring and watch them sink through the oil.
Drop in a ¼ tablet and watch the "lava."
Cap it and take it home with one extra tablet piece.

Ask, instead of explaining: Where do you think the bubbles come from?

Learn: the idea

Oil and water don't mix. Oil is less dense than water, which means it is lighter for the same amount, so it floats on top. The fizzy tablet makes bubbles of gas that grab some colored water and carry it up. When the bubble pops at the top, the water sinks back down.

Prep

Fill small plastic bottles with oil and water.
Cap them tight.
Break tablets into quarters.

Crew for prep: 2 people, about 1.5 hr. Prep happens on the day, from 12:15.

During the event: 2 volunteers. Setup about 20 min. One hands out bottles, one handles tablets and color

Tips

Pre-fill the bottles with oil and water before the event. An assembly line the afternoon before works well. Cap them tightly.
Pre-break the tablets into quarters and keep them in a cup.
The kid's job is to add 2 drops of color, drop in a tablet piece, and watch. Then cap it and take it home.
Use small bottles (8 oz or smaller). They need less oil and spill less.

Safety

Do not drink it.
Never cap it while it is still fizzing.
Tablets are medicine: keep from little kids.
Wipe up oil: it is slippery.

Turbo (only if we choose to)

Glow lamps: put the bottle on a waterproof LED tea light (we may already have some), or use tonic water instead of plain water. The quinine in tonic glows bright blue under a UV flashlight.

Clean up

Wipe the table and put reusable items in your tote.
Bag the trash and wash hands.
Log anything borrowed so it can go back.