Rosh Yeshiva Responds
Rabbi Linzer answers halakhic questions from rabbis and community members

1 02, 2024

Traveling by Electric Scooter on Shabbat

February 1st, 2024|Choleh, Prohibitions, Shabbat, Synagogue, Technology, Tefillah|



I have a congregant who can no longer walk to shul. I have discussed the option of using the Grama scooters approved by Zomet and the Star K, but they cost more than $4000. She is able to purchase a “regular” used scooter for only $400. Would the financial savings justify using a regular scooter on Shabbat (perhaps with using a shinuy)?

Do you have any advice for

1 12, 2023

Using “Water Wow!” Toy on Shabbat

December 1st, 2023|Orach Chayim, Prohibitions, Shabbat, Shulchan Arukh, Technology|



Would it be permissible to use the Water Wow! toy on Shabbat? Assuming that it is, at the very least, uvda d’chol, what are other issues are there?

Here’s a description of how it works:

The basic concept is that each page is “laminated” with a very thin sheet of paper – almost like tissue paper, but more durable. When the paper is moistened by the water in the pen, it becomes see-through and reveals the picture underneath. There’s no chemical reaction involved.


Had it been that the water was interacting with some chemical to create the color, it obviously would be

23 04, 2023

Using an Electronic Based Toilet Training System on Shabbat

April 23rd, 2023|Orach Chayim, Prohibitions, Shabbat, Technology|


Baltimore, MD

There is a family who is using a nighttime toilet training program for their 9-year-old son. The program requires a magnetic sensor that triggers an alarm system. The alarm needs to be turned off and reset when it goes off. What options do they have to continue to use the system on Shabbat? They are concerned that stopping will break up the continuity of his toilet training.


I think it’s fine with a shinuy. I think bedwetting issues can be a source of a lot of psychic angst for

9 02, 2023

Adjusting the Temperature on an Electric Countertop Burner on Yom Tov

February 9th, 2023|Electricity, Orach Chayim, Technology, Uvda D'Chol, Yom Tov|


Chicago, IL

If I have an electric countertop burner that I put on a timer for yom tov, can I adjust the heat setting while the burner is on? Does it matter if I’m turning the heat up when the burner is already on or down when it’s already off (there’s a light that says if it’s currently heating or not)?

Do you have general guidelines on interacting with electronic devices on Shabbat/Yom Tov?


There are two issues here—havarah/mekhabeh (igniting/extinguishing), and use of electronics.

1. Regarding havarah/mekhabeh (igniting/extinguishing)

29 01, 2023

Sous Vide—Tevilat Keilim and Warming Food on Shabbat

January 29th, 2023|Bishul, Kashrut, Orach Chayim, Shabbat, Technology, Tevilat Keilim, Yoreh De'ah|

New York

Two questions regarding a sous vide:

1) Does it require tevilah?
2) Can it be used to reheat food on Shabbat, assuming it is on and in heated water from Erev Shabbat?


1. It does not require tevilah. It does not come in direct contact with the food (plastic bag and water both intervene). (Shulchan Arukh YD 120:4, Arukh HaShulchan YD 120:32, Sefer Tevilat Keilim, 1:4 ft. 7)


25 02, 2021

COVID Vaccine on Shabbat

February 25th, 2021|Choleh, Orach Chayim, Prohibitions, Technology|


Washington, D.C.

What should the approach be for a vaccination appointment on Shabbat, assuming that is the only appointment available? I just saw someone on Facebook who was able to book one but saw it was on Shabbat and canceled it before any of us could tell her she should go! So upsetting. Is there any guidance being provided on this?


I’ve been struggling over this – how much is preventative medicine like a choleh with the same heteirim?  In this case, where the need is so great, I would say it can be categorized as such, but only after looking at options.  Will

12 02, 2021

Speaking Machine on Shabbat for Person Who Lost Ability to Speak

February 12th, 2021|Choleh, Orach Chayim, Technology|


Maryland, USA

Someone with a serious illness in my shul recently lost the ability to speak. He now has a machine that he can type his words and it speaks it for him. May he use the machine on Shabbat? Without the machine he’d be unable to communicate.


Yes. It is clearly a case of mitztaer that would permit derabanans. I should note that some people might say, “If he can do that, then why can’t I…” (I think more than they would say this in a case of, say, an electric wheelchair). So you should just be aware of that, and

24 01, 2021

Wearing a Seiko Spring Drive Watch on Shabbat

January 24th, 2021|Orach Chayim, Prohibitions, Technology|


Chicago, IL

Can a watch like this be worn on Shabbat. The battery is charged by the movement of the wearer. But, when Shabbat begins, the battery has enough charge to last 3 days. (And the mechanism is a merger of self winding spring mechanism and quartz powered regulator for accuracy).


I can’t see how it can be a problem. It is totally mitaseik, or at most pesik reisha delo ikhpat lei. It’s probably even

27 12, 2020

Does a Water Urn Require Tevilah? May It Be Used on Shabbat?

December 27th, 2020|Orach Chayim, Prohibitions, Technology, Yoreh De'ah|



Newly purchased water urn – do you hold that it’s patur from tevilah because it’s mechubar lakarkah (and maybe will get ruined by tevilah? not sure the metziut) or that it requires tevilah as per Rav Moshe? See the picture for reference.



I think you don’t need to do tevilah based on the combination of the following 3 reasons (any 2 would really suffice):

  1. Mechubar