6
votes
1answer
105 views

Is it permitted to use a thermochromic cup on Shabbos?

A novelty cup, see for example here, appears black when cold. When hot liquid is poured into it, the black changes to white and the previously concealed writing (underneath, so to speak) becomes ...
1
vote
0answers
70 views

Typing on Shabbos

If one would type on a computer on Shabbos would he be ovar an issur d'oraisa in regards to the malacha of writing? (The other malachos involved aside for a moment.) Is there any room to say this ...
11
votes
2answers
357 views

Why does writing on Shabbos need two letters?

In order to transgress "writing" (כותב) on Shabbos, (m'd'oraysah) one must write two letters. (See for example here.) Why is this so? Shouldn't writing anything still be considered writing? For ...
3
votes
2answers
96 views

Self-study writing a davar avid?

If I am teaching myself a foreign language as a leisure activity, may I write in a workbook on chol hamoed, for the purpose of retaining my knowledge? If I haven't begun, may I start the new language ...
6
votes
3answers
304 views

Typing on Chol Hamoed

Is typing allowed on Chol Hamoed? Does it make a difference if whatever is typed will be printed afterwards?