Can you take ice on a plane?

I was on a plane earlier today and was really thirsty. I thought about how I wished I’d taken an empty water bottle in my bag, but I didn’t like the thought of warm tap water later, after the chill of the water fountain wore off.

This leads me to my question. I thought it would be a good idea to freeze water in a water bottle, but wondered if they would allow it through security. My friend who is training to screen bags said it counts as a liquid, but it doesn’t seem right to me because it violates science! After all, ice is a solid, right?