Question

which of the following observations best demonstrates water’s special property of cohesion? a. a spoon held near a stream of water from a tap deflects the water towards itself. b. a rainbow forms after a rain storm. c. water forms droplets of dew on a spider web in the morning. d. water can dissolve other substances, such as sugar and salt.

Explanation:

To determine which observation demonstrates water's cohesion (attraction between water molecules), we analyze each option:

• Option A: A spoon deflecting water likely shows adhesion (attraction between water and another substance, like the spoon) or static electricity effects, not cohesion.
• Option B: A rainbow forming is due to light refraction, reflection, and dispersion in water droplets, unrelated to cohesion.
• Option C: Water forming dew droplets on a spider web shows adhesion (water to web) and surface tension (from cohesion, but the main interaction here is with the web). However, the key for cohesion is water molecules sticking to each other. Wait, no—dew formation involves condensation, but the droplet formation on the web: actually, when water forms droplets on a surface, if the surface is non - polar (spider web might be), water molecules stick to each other (cohesion) more than to the web (adhesion), forming droplets. But let's check Option D: Water dissolving substances is solubility, related to polarity and solvation, not cohesion. Wait, maybe I made a mistake. Wait, cohesion is the attraction between water molecules. Let's re - evaluate:
• Option A: If the spoon is charged or has adhesion, but cohesion is water - water. Option C: Water forming droplets on the web—inside the droplet, water molecules are attracted to each other (cohesion) which helps form the droplet. But wait, the question is about cohesion. Wait, another way: Cohesion is what makes water form droplets (like dew) or have surface tension. But let's check the options again. Wait, maybe the correct answer is C? Wait, no, let's think about each:
• Option A: Deflection by a spoon—maybe electrostatic or adhesion. Not cohesion.
• Option B: Rainbow—optics, not cohesion.
• Option C: Water forms droplets of dew on a spider web. The formation of droplets is due to cohesion (water molecules attracting each other) and surface tension. The water molecules stick together to form the droplet, even on the web.
• Option D: Solubility—different property.

Wait, but maybe I was wrong earlier. Let's confirm: Cohesion is the intermolecular attraction between like molecules (water - water). Adhesion is between different molecules (water - other). So when water forms droplets (like dew), it's because the cohesion between water molecules is stronger than the adhesion to the surface (if the surface is non - wetting). So Option C shows water molecules sticking together to form droplets, demonstrating cohesion. Option A: If the spoon is attracting water, that's adhesion (water - spoon) or maybe electrostatic, not cohesion. So the best answer is C? Wait, no, wait the original options: Wait, the user's image: Option A: A spoon held near a stream of water from a tap deflects the water towards itself. That could be due to electrostatic attraction or adhesion, but not cohesion. Option C: Water forms droplets of dew on a spider web. The droplets are formed because water molecules are attracted to each other (cohesion), so they clump together into droplets. So that demonstrates cohesion. Option D is solubility, Option B is optics. So the correct answer is C. Wait, but maybe I made a mistake. Wait, let's check again. The question is which BEST demonstrates cohesion. Cohesion is water molecules sticking to each other. So when water forms droplets, that's cohesion. So Option C: Water forms droplets of dew on a spider web—yes, because the water molecules are attracted to each other, forming the droplets. So the answer is C.

Answer:

C. Water forms droplets of dew on a spider web in the morning