Deployed spouse....gender reveal!

So my husband is deployed, I want to do a gender reveal with my daughters that I will record and send him that way it's a cute exciting way for him to find out our third childs gender.

I just don't know what to do as I'll be visiting family in Florida. My girls are 4 and 2 so I want it to be obvious blue or pink and make it super fun for them.

Throw me your ideas..... Please!!!