This is an easy and fun activity for the whole family, especially when the temperatures get's really cold. You may find your children will be spending more time outside arranging, rearranging, and adding on to their ice sculpture.
Caution: Please keep an eye on young children and limit their time outside when it is very cold. Children sometimes do not realize that they may be in danger of frostbite or hypothermia.
First, get an assortment of balloons ranging from traditional balloons to balloon sculpting (snake) balloons.
Next, put a couple grains of sand into each balloon. The sand will act as a freezing nuclei for the water. Without it, some of the water in the balloons may not freeze. To learn more about this effect, look up "superchilled", "super cold", or "super freezing".