Once you buy the bubble machine you can, of course, use it wherever you want. However, you should bear in mind that bubbles on a hard floor create a sticky and slippery surface that can prove dangerous for little feet. Carpeted areas will prevent the surface from becoming slippery, but if you saturate the carpet, you may damage the fibers or ruin the padding underneath it with mold. Water damage from bubbles may not be a huge risk, but it’s worth considering. If you only have a bubble wand, you can certainly get away with bubbles inside, but a bubble machine makes significantly more bubbles with which to contend. It isn’t a hard and fast rule, but generally, a bubble machine is best for outdoor use.