Hello! What would be the substance, chemical reaction and technique, to have the highest rate of immediate mass change, back and forth, from low to high and back to low again, as many times as needed - using only homemade DIY, non dangerous materials and equipment? My intentions are to deal in the range of 1-250 grams. What would be the change under these DIY home limitations? Would it be a change of between, say, 10 grams and 10.2 grams or is there some marvelous material mass transforming 'magic', that can make 10 grams become 100 grams, almost instantly and then again, almost instantly or when needed, back to 10 grams? I understand that this questions might uncover some basic misunderstanding of some elementary modern physics principles (i hope not of classical physics as well...), but that's the situation here and we shall appreciate a detailed, as well as simple answer as possible! Thanks!