Sharp in music means that a note is being played or sung higher than the usual pitch. Think about how a balloon when you blow it up gets bigger and bigger, that's what happens to the note when it gets sharper. Just like how a balloon can pop if it gets too big, if a note gets too sharp it can sound unpleasant to our ears.
To show that a note is sharp, a symbol that looks like a hashtag (#) is placed in front of the note on the sheet music. This reminds the musician that they need to play or sing the note a little bit higher than they normally would.
Musicians use sharps to create different emotions and feelings in music. Sometimes a song needs to sound happy and upbeat, and sharp notes can help with that. Other times a song might need to sound sad or painful, and using sharp notes can add to that feeling.
So, when you see a sharp symbol on sheet music, think of it like a balloon getting bigger and higher. It's a way to make the music sound different and give it more emotion.