[Patrick and his two-year old Sam have been playing in the snow in Prospect Park and are now on their way to get hot chocolate at Parco, a nice cafe on 7th ave.]
Sam: (points to a truck) What's that?
Patrick: That's, um, that's a salt truck. Those trucks drive all around the city when it snows or ices, and they spread salt on the road and when the salt mixes with the ice, it lowers, I think this is right, it lowers the freezing point of the ice to something that's, you know, below the current temperature so even if it's freezing outside, the ice that's mixed with the salt needs a lower temperature than that to stay frozen, and so the salt makes the ice melt so cars can drive on it.
Sam: What does pepper do?