Question

Which of the following observations is best explained by water’s high surface tension? Choose 1 answer: (choice a) A leaf floats on the surface of a puddle. (choice b) A local pond is slow to freeze, despite low air temperature. (choice c) A tree takes up water from its roots. (choice d) A human sweats in order to cool down.

Answer 1

Water's high surface tension, a result of the cohesive forces between water molecules, explains why a leaf can float on the surface of a puddle.

Step-by-step explanation:

The best explanation for the observation that a leaf floats on the surface of a puddle is due to water's high surface tension, which is caused by the cohesive forces between water molecules. This cohesion is the attraction between the water molecules, which allows for the creation of a type of 'skin' on the water's surface where the molecules are held tightly together. This surface can support light objects, such as leaves, and even enable some insects to walk on the surface of water without sinking.

Answer 2

A leaf floating on a puddle exemplifies water's high surface tension. This phenomenon occurs due to the cohesive forces between water molecules at the surface, allowing a 'skin' to form that can support weight.

Step-by-step explanation:

The best explanation for an observation that is accounted for by water's high surface tension is: (choice a) A leaf floats on the surface of a puddle. Surface tension is a result of the cohesive forces between water molecules, particularly at the water's surface, where the molecules are not surrounded by similar molecules on all sides. This leads to water's ability to create a surface strong enough to support the weight of small objects, such as a leaf. Hence, the leaf's ability to float is because of the high surface tension of water, allowing it to form a sort of 'skin' that can support the leaf's weight. While cohesion and adhesion are both properties of water and important in processes such as capillary action observed in plants, in the context of this question regarding surface tension, the ability of a leaf to float is the most relevant.