The idea of creating balls out of sand, sounds strange in the first moment but it really works surprisingly well. I have seen this the first time at Zach Pine's facebook page Earth in Your Hands - Sand Globes Worldwide and some tutorial videos published on this side, thanks at that point for this nice sharing.
Water is the trick for creating Sand Globes, its the water between the sand grains which keeps them in shape. Once you figured the amount of moisture it is quite easy to make. This said I have to add that some sand can be very difficult while others work much better for that. If its the right sand and mixture those balls can be quite strong and you can even try to stack them, or what ever else comes to your mind.
have fun ...
For more infos about Sand Globes wisit the official Earth in Your Hands website: