Question

When water flows from a faucet, the water molecules tend to join together and form a stream. Which of the four fundamental forces most likely accounts for this, and why?

Answer 1

Sample Response:  The water molecules are attracted to each other because of the electromagnetic force.

Answer 2

The fundamental force responsible for the cohesion of the water molecules leaving the faucet is the electromagnetic force.
Electromagnetic forces act on particles that are electrically charged. Water molecules are polar, which means that they have a positively charged end and a negatively charged end. This polarity arises from the fact that oxygen pulls the electrons in the molecule towards itself and attains a negative charge, while the hydrogen atoms in the molecules are left with a positive charge.