Right thumb on top - right handed.
right-handed and my right thumb is on top.
Right thumb on top, right handed. I recently had 7th graders. Great book on projects like this: Science Fair Success Secrets. Here's the Amazon link: http://www.amazon.com/exec/obidos/tg/detail/-/0525465340/qid=1108696330/sr=8-1/ref=sr_8_xs_ap_i1_xgl14/002-3562705-9719255?v=glance&s=books&n=507846
Left thumb on top. Right handed. Tried it the other way. Felt very uncomfortable.
Right-handed. Right thumb on top
Right handed,left thumb on top.