Is it true that burying ice in soil or covering it with sawdust keeps it from melting for a long time? I asked an AI. For summer vacation independent research.

It is true! It becomes much harder to melt and lasts a long time.

In the days before electricity and refrigerators, facilities called "Himuro" (ice houses) were used to store natural ice made in winter until summer, and they used exactly this method of combining "soil" (caves or semi-underground structures) with "sawdust, rice husks, or thatch."

Even today, traditional natural ice makers store ice using sawdust inside ice houses.

Why does it become harder to melt? (3 reasons)

1. The "layer of air" acts as a natural insulator
Sawdust, which is created when wood is shaved, contains a lot of air in its tiny gaps. Because air has the property of being very poor at conducting heat (insulation), it acts like Styrofoam, blocking out the warm outside air.

2. It blocks direct sunlight and the movement of outside air
By covering the ice with soil or a thick layer of sawdust, sunlight (radiant heat) no longer hits it directly. Furthermore, it can prevent the phenomenon (convection) where warm wind brushes against the surface of the ice and melts it.

3. It absorbs moisture and improves drainage
If ice is submerged in "meltwater," heat is easily transferred through the water, causing it to melt rapidly. Sawdust and soil absorb the meltwater and drain it away, keeping the area around the ice dry.

> Trivia: What happens if you bury it directly in just soil?

> While soil has an insulating effect, if moist soil comes into direct contact with the ice, the heat from the soil itself is transferred to the ice, causing it to melt, or it becomes covered in mud and unusable.

For this reason, people in the past used the wisdom of "wrapping the ice in cloth or straw, packing a large amount of sawdust around it, and then placing it in a dirt hole (or ice house)."

The wisdom of our ancestors is amazing!!