Fun for 4 year olds.

JOEBunny

I got a package with dry ice in it.  I put water in the sink with some soap and put the ice in it.  DD has a friend over, so I called them to see, "What is happening in my sink?"  Needless to say bubbling smoke coming out of the sink was a huge hit and they had a great time popping the bubbles to let the smoke out.  I think they were a bit disappointed to find out what was really going on, but their theories were pretty entertaining.

peekaboo716

DS would love that!

jlw2505

We have done that with our kids before.  Just make sure they don't touch it - DH did by mistake once and it burns!