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Hourglass Sand Timers on Shabbat


Rabbi David Sperling

Tammuz 15, 5780
Is it permissible to use a sand timer like that described below on Shabbos ? Sand Timer Foxnovo Colorful Sandglass Hourglass Sand Clock Timer 30sec 1min 3mins 5mins 10mins 5pcs Random Color Sold by: Uwitstar $6.99
Shalom, Thank you for your question. The use of a sand timer on Shabbat is an interest one. While the act of turning over the hourglass and letting the sand run through is not a problem, the question of measuring comes up. One answer given on our site, by Rav Moshe Leib Halbetstadt, is as follows - "One should not use an hourglass with lines on Shabbat, unless it is for the purpose of a Mitzvah. It is Muktzeh and should not be moved in accordance with the law of Keli Shemelachto L'Issur (a utensil designated for prohibited use) unless it's for the purpose of using the object itself for a different, permissible use (Tzorech Gufo) or for the space it occupies (Tzorech Mekomo).(שלחן ערוך או"ח סימן שח סעיף נא ומ"ב ס"ק קסה). Regarding a sand timer which has no lines but a fixed time such as two or three minutes, one who is lenient and uses it on Shabbat has whom to rely on, and one who is stringent and refrains will be blessed. (פרמ"ג או"ח סימן רנב במשבצות זהב ס"ק ז, לבוש סימן שח סעיף נא, והובא גם בכף החיים אות רסט וע"ע באות רעג). " The reason for the questionable use of a sand hour-glass is that it is forbidden to measure on Shabbat (except for the preformance of a mitzvah). The issue here is twofold. Firsty, is it also forbidden to measure time? This question was debated by the Rabbis, and the general tendancy is to rule strictly and forbid even the measure of time. However, a second issue arises, which is that perhaps not every use of the hourglass is actually measuring time. One could say that when used in a game to give each player a turn, 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. Several modern Rabbis rule like this (Rav Shlomo Zalman Aurbach zt"l raises this possiblity). See also Tzitz Eliezer (Vol. 3, no. 10), who writes that only measuring for measurement’s sake is considered a forbidden weekday activity, because it relates to the initial decree (such measuring was prohibited on account of the concern for business dealing and for writing). Based on this, there is room to use such a sand hourglass in a game. However, if you were to use it to really time the length of something (for example to take it to Shule to time the length of the Rabbi's sermon) one should certainly be strict. Blessings.
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