Melted wax cooling: time lapse

The candle is sitting on a small electric warmer that melts the wax. It's difficult to see in the video but at the end you may notice the formerly flat surface of the wax assumes an interesting concave shape (the wax is at the same level around the edge whether melted or cooled, and the wax in the middle sinks perhaps a half inch lower). I believe this is because the hot glass keeps the wax at the outer edge warm for longer, so the wax in the center cools first.

Category:

Science & Technology

Tags:

• time
• lapse
• wax
• candle

[ct6mblack]

The reason why the concave shape occurs is because wax shrinks when it cools and expands when heated. The outside/top of the wax will begin to cool first, leaving the middle relatively warm (and sometimes liquid for a while). When the inside begins to cool, it has to shrink down as well, and since the wax is not completely hardened yet, it is essentially sucked into the middle as it cools. It's quite an interesting sight. I've experienced it a lot with my candle-warmer. Cool vid!