Fill the balloon with water . This image illustrates why you don't completely fill the balloon you should always leave some room in the neck of the balloon, then as the form dries the pressure has somewhere to go and your clay wont split like that.
National Air and Space Museum (NASM) in Washington, DC. Explore amazing variety of planes and rockets as well as crafts of all sizes and shapes from a variety of different eras as well as places. It also aeronautic research center.
The National Gallery of Art in Washington D.C. is perhaps one of the most important museums in the USA. The collection is varied and there are many surprises hidden in it
California Academy Of Sciences is the largest natural history museums in the world. It is home to an Aquarium, Planetarium, Natural History Museum, Rainforest, 40,000 live animals and more.