The temperature that water density become maximum.

Generally, solid has higher density than liquid, but water is different.

The temperature that water density become maximum is around 3.98 degrees Celsius .

When water freeze and become ice, the volume will increase and the density will decrease, because the crystal structure have a lot of gaps.

However, if the ice is melting a little, the volume will decrease and the density will increase, because the water molecules will get through the gaps of the crystal.

Also, if the temperature exceed 3.98 degrees Celsius, the volume will decrease but the density will also decrease, because the intermolecular distance of the water will increase.

For these reasons, ice float on water.

You might feel that this phenomenon is natural, but it's really special and rare.

一般的に固体は液体よりも密度が高いですが、水の場合は違います。

水は約3.98℃のとき、密度が最大になるのです。

水は凍ると、隙間の多い結晶になるため、体積が増加して密度が下がります。

しかし少し溶けた状態だと、結晶の隙間に水分子が入りこむため、体積が減少して密度が上がります。

また、3.98℃を超えると、体積の減少よりも分子間距離が長くなる影響が大きくなり、密度が下がります。

このような理由から、氷は水に浮かびます。

この現象は自然に感じるかもしれませんが、実は非常に特殊なことなのです。

• Generally, solid has higher density than liquid, but water is different.
• Generally, solids have a higher density than liquids, but water is different.

• The temperature that water density become maximum is around 3.98 degrees Celsius .
• The temperature that water density is maximized is around 3.98 degrees Celsius.

• When water freeze and become ice, the volume will increase and the density will decrease, because the crystal structure have a lot of gaps.
• When water freezes and becomes ice, the volume increases while the density decreases, because the crystal structure has a lot of gaps.

• However, if the ice is melting a little, the volume will decrease and the density will increase, because the water molecules will get through the gaps of the crystal.
• However, if the ice is partially melted, the volume decreases while the density increases, because the water molecules can fit through the gaps of the crystal.

• Also, if the temperature exceed 3.98 degrees Celsius, the volume will decrease but the density will also decrease, because the intermolecular distance of the water will increase.
• Also, if the temperature exceeds 3.98 degrees Celsius, the volume decreases, but in this case, the density will also decrease, because of the increasing intermolecular distance of the water.

• For these reasons, ice float on water.
• For these reasons, ice floats on water.

• You might feel that this phenomenon is natural, but it's really special and rare.
• You might feel that this phenomenon is natural, but it's actually very special and rare.