When something is palpable, you can touch or handle it, even though the word is often used to describe things that usually can't be handled or touched, such as emotions or sensations.
You probably won't see palpable used to describe, say, an egg or a doorknob or a motorcycle. Palpable is usually reserved for situations in which something invisible becomes so intense that it feels as though it has substance or weight. Someone who has experienced a death in the family might say that her grief feels palpable.