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Sabbath mode

Sabbath mode is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sabbath mode rather than just read about it. In short: Sabbath mode, also known as Shabbos mode (Ashkenazi pronunciation) or Shabbat mode, is a feature of some modern home appliances, including ovens, dishwashers, and refrigerators, which is intended to allow the appliances to be used (subject to various constraints) by Shabbat-observant Jews on the Shabbat and Jewish holidays. The mode usually overrides the usual, everyday operation of the electrical appliance and make…

Sabbath mode — main illustration
Sabbath mode — illustration

Key takeaways

  • Sabbath mode belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Sabbath mode to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Sabbath mode from memory before moving on to harder problems.

Reference excerpt

Sabbath mode, also known as Shabbos mode (Ashkenazi pronunciation) or Shabbat mode, is a feature of some modern home appliances, including ovens, dishwashers, and refrigerators, which is intended to allow the appliances to be used (subject to various constraints) by Shabbat-observant Jews on the Shabbat and Jewish holidays. The mode usually overrides the usual, everyday operation of the electrical appliance and makes the operation of the appliance comply with the rules of Halakha (Jewish law).

Background Halakha forbids Jews from doing "work that creates" on Shabbat. Some observant Jews interpret this to include various activities including making a fire, preparing food, or even closing a switch or pressing an electronic button. A range of solutions has been created for those who need to use electronic (or electronic-controlled) devices on the Shabbat, including a special "Sabbath mode" for otherwise standard appliances.

Appliances

Oven

While according to Halakha, raw food may not be cooked on the Shabbat, food that was already cooked beforehand may be kept warm until mealtime. In the past, the Sabbath-observant would leave their food heating on the stove where it had been covered with a blech (metal sheet), or in the oven in which it had been cooked before the onset of Sabbath. Contemporary consumers seek to use their kitchen's oven to keep food hot for Sabbath consumption but must be assured that in opening the door to retrieve food, no Sabbath laws will be inadvertently contravened. An example of this would be ovens which are programmed to remove power from their heating element when the door is opened – use of this oven would not be possible on the Sabbath without making modifications. On weekday holidays (Yom Tov), food may be cooked, but turning the heat on is prohibited. On these festive days, the domestic needs of the Sabbath observant consumer may require that their oven be heated over as much as 72 hours to allow for cooking during the festival. In the past, one would simply light a stove or oven before the festival began, and its heat was used over the coming days. In recent decades, however, appliance manufacturers have instituted safety features that present a challenge to festival use. One typical challenge is the auto-shut-off which automatically shuts off the heat after a predetermined number of hours. For an appliance to be compliant with religious requirements when Shabbat mode is operating, the standard six- or twelve-hour automatic shutoff should be overridden, and all lights and displays (for example, a light that might go on when the door is opened) should be disabled. However, several manufacturers have not dealt with the issues caused by the heating elements and the thermostats, which in some Sabbath modes continue to operate as normal, which is in contradiction to normative halachic opinion. Some models do not even take care of the issue of the lights. In more recently designed ovens, Shabbat mode will often feature the ability to adjust the temperature of the oven without any feedback to the operator of the oven. According to the prevailing Orthodox opinion and the minority Conservative view, this is not relevant to the Shabbat, but is useful on some holidays, when adjusting the heat is allowed, but changing a digital readout on the control panel is not. With some Shabbat mode ovens that are controlled using a keypad to set the temperature, there is a random delay triggered after a button is pressed before the temperature change takes place. In June 2008, nine Haredi poskim signed a public pronouncement (Kol Kore) stating that it was forbidden to raise or lower the temperature by reprogramming on Yom Tov using the Star-K Kosher Certification approved Shabbat Mode feature. The pronouncement referred to the differing opinion of Rabbi Moshe Heinemann (although without explicitly mentioning Rabbi Heinemann by name) as a minority opinion (Da'as Yachid) that should not be relied upon. However, Rabbi Heinemann said that he continued to stand by his opinion that it is permissible.

Refrigerator

A Shabbat mode refrigerator includes, at a minimum, the ability to disable all lights or other electrical activity from occurring when the refrigerator door is opened. Some Shabbat mode refrigerators include a timer for the compressor so that opening the door, which would normally indirectly cause the compressor to turn on as soon as the temperature rises, will have no immediate effect on the electrical operation of the appliance. Other refrigerators have their automatic functions removed. So, the user doesn't turn on the light when they open their fridge, making the Shabbat mode refrigerator okay to use on Shabbat.

Lamp

A Shabbat lamp is a special lamp that has movable parts to expose or block out its light so it can be turned "on" or "off" while its power physically remains on.

See also 39 categories of activity prohibited on Shabbat Blech – a metal sheet used to cover a stovetop on Shabbat. Cholent – a long-simmered stew often eaten for lunch on Shabbat. Grama (halacha) – something that was caused by something else but whose outcome is not guaranteed. Shabbat elevator – an elevator with an automatic mode to allow observers to abstain from operating electric switches on Shabbat.

References

External links

Reference in 1994 KitchenAid marketing literature View All The Kashrus Kurrents Articles Using an approved ‘Sabbath Mode’ on Shabbos – The Federation of Synagogues An early Sabbath mode patent: US patent 5808278, Chang Hwan Moon, Jonathan T. Smith, "Electronic appliance and a sabbath mode therefor"

Illustrations

Sabbath mode: A refrigerator displaying the Sabbath Mode
A refrigerator displaying the Sabbath Mode

Worked examples

Example 1 — a first encounter with Sabbath mode

Start with the simplest possible case. Write down what Sabbath mode claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sabbath mode before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sabbath mode ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sabbath mode

In research
Sabbath mode appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Sabbath mode in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Sabbath mode is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cooking appliances, Shabbat innovations, so understanding it makes those chapters shorter.
In everyday life
Look for Sabbath mode outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sabbath mode in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Sabbath mode means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Sabbath mode out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sabbath mode in simple terms?

Sabbath mode, also known as Shabbos mode (Ashkenazi pronunciation) or Shabbat mode, is a feature of some modern home appliances, including ovens, dishwashers, and refrigerators, which is intended to allow the appliances to be used (subject to various constraints) by Shabbat-observant Jews on the Sh…

Why does Sabbath mode matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sabbath mode?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sabbath mode.

Tags

  • Cooking appliances
  • Shabbat innovations

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