Can you use a sand timer on Shabbos in a game, for example in Articulate?
There is room to permit using a sand timer on Shabbos for a game, in particular for children.
There is a rabbinic prohibition against making measurements on Shabbos (see Shabbos 157a), which is based on the concept of uvdin de-chol (Tosafos, Shabbos 126b).
It is not clear whether of not this applies even to measurements of time, and the Maharil (no. 200) writes that after consultation with a great Torah authority and not receiving a clear answer, we cannot be lenient in the matter.
This is ruled by the Beis Yosef (Orach Chaim 308) concerning laws of muktzeh. Although authorities permit using a watch and clock, this is because looking at a watch does not involve an act of measuring. Where there is an act of measuring, however, it appears that it is not permitted to measure time.
However, in the case of a sand timer, there is room to argue that this not a “measure” of time, but rather an indication that the person’s turn is up. The timer is not used to measure a time duration, but rather to indicate that the respective player’s turn is up.
A similar concept is raised by the Raavyah (no. 377), who writes that where the purpose is not to quantify time, the measurement is considered mis’asek, and no prohibition is involved (see Tur 306).
In addition, Rav Shlomo Zalman Auerbach (Shulchan Shlomo 308) notes that it might be permitted to use a mercury thermometer on Shabbos (absent the issue of the sickness), because there is no uvdin de-chol in measuring fever, which is a special category of measuring and doesn’t fall under the uvdin de-chol of ordinary measuring. He continues to say that based on this there is room to permit the use of sand-clocks in games.
See also Tzitz Eliezer (Vol. 3, no. 10), who writes that only measuring for measurement’s sake is considered uvdin de-chol, which relates to the initial decree (such measuring was prohibited on account of the concern for business dealing and for writing).