Final answer:
An ice cube floats higher in salt water due to its increased density compared to fresh water. Furthermore, a melting glacier on land would contribute more to the rise in a lake's level than a melting floating iceberg, which already displaces water equal to its weight.
Step-by-step explanation:
An ice cube will float higher in salt water compared to fresh water because salt water is denser due to the dissolved salts. This increased density results in greater buoyant force on the ice cube, causing it to float higher. According to Archimedes' Principle, the volume of water displaced by the submerged part of the ice cube equals the volume that would be displaced by the ice cube's weight in water. Since salt water is denser, a smaller volume of it will match the ice cube's weight, meaning a larger portion of the ice cube remains above the surface.
In terms of the question about the iceberg and glacier near the North Pole: if both chunks of ice should melt, the glacier on land would contribute more to the rise in the lake's level. This is because the iceberg floating in the lake is already displacing water equal to its own weight, and thus its melting would not significantly change the water level. On the other hand, the melting glacier on land would add all its water to the lake, resulting in a higher increase in the water level.