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The prohibition of Molid (making creative changes to a substance or creating a new entity on Shabbat) is general in nature and has many applications. 
Crushing and Melting Ice
- One may not crush ice on Shabbat, but one may place ice cubes into a cup of water and have them melt on their own.
- It is best not to place the ice cubes in the empty cup and then pour water on top of the ice to chill or cool the water since doing so is inevitably going to melt the ice.
- One may walk on ice or snow on Shabbat and it is not a concern of melting ice.
- One may melt ice on shabbat if the water which comes out goes to waste. Therefore, ice can be disposed of in the sink, or one may cool a bottle with ice. 
- One can put out salt on ice or snow so that people can walk since one's intent isn't for the ice and one isn't actively melting the ice.
- One may place ice into a cup of liquid but one shouldn’t accelerate the melting by pressing the ice.  According to Sephardim one may shake the cup even if that accelerates the melting. 
- One shouldn’t put ice in a cup in order for the ice to melt and drink the water. If one did so, it’s advisable not to use the water but it’s not forbidden. 
- One should not place ice in a cup and intend to drink it when it melts. 
- One should not have a frozen milk or juice container melt or thaw unless there's an important need for the liquid. 
- One may break ice cubes that are frozen together in an ice tray because one does not intend to produce water from the breaking.
- One may pour some water over the ice cubes so that he would be able to remove the ice cubes from the ice tray. 
Making Ice on Shabbat
- One shouldn’t make ice on Shabbat unless one feels that one really needs them on Shabbat. Some permit making ice for Shabbat under all circumstances. Sephardim are lenient and allow one to make ice on Shabbat.
- One may put food into the freezer or refrigerator.
- One may remove food from the freezer in order to thaw in order to eat it on Shabbat but not if it won’t be ready until after Shabbat. 
- It’s permissible to melt ice cream in order to eat it as long as one doesn’t put in a place of 113 degrees. 
- One shouldn’t make ice cream from powder on Shabbat unless it’s a thin mixture, one puts the ingredients in the reverse order than usual, and one stirs it differently. 
Cooling a hot pot
- A may not place hot (over 113 degree) solid food or a Kli Rishon in cold water. However, one may place a Kli Sheni into cold water. 
Using whipped cream
- Some poskim hold that it is forbidden to use whipped topping or whipped cream from a can on Shabbat.  Others however, disagree.
The gemara Shabbat 51b writes that one may not crush now but may place it into a glass on Shabbat. There are a few different approaches to why it would be prohibited to crush snow:
- Rashba there explains that the prohibition is based on the prohibition of sechita (squeezing), that just as it is forbidden to squeeze fruit it is forbidden to squeeze ice. Maggid Mishne Rambam Shabbat 21:13 writes that the Rambam agrees with this Rashba.
- Rashi 51b “kdei” writes that you are being “molid” on Shabbat, and it is like a melacha. The Rosh 4:13 understands the sefer hateruma 234-235 as saying a similar idea
- The aforementioned Rashba quotes the sefer hateruma 234-235 understands that the problem is based on the muktzeh category of nolad. Since the result will be muktzeh since it is a newly created item, it would be prohibited.
- Gemara Shabbat 51b, Shulchan Aruch 320:9, 39 Melachos (vol 2, pg 364, 368), Shemirat Shabbat KeHilchata 1:74, Yalkut Yosef 320:31
- Piskei Teshuvot 320:14 writes that it is best not to place ice in a cup and then pour water on top of it to cool the water since pouring the water melts the ice. In fnt. 154 he cites the Migdanot Eliyahu 2:105 who isn't certain if it is permitted. Shabbat Khalacha 17:3 is also strict. See Minchat Shay 320:9. Rav Mordechai Eliyahu in Sh"t Maamar Mordechai 4:83 is lenient.
- Rabbi Mansour on Dailyhalacha.com, 39 Melachos (vol 2, pg 368), Mishna Brurah 320:39, Yalkut Yosef (Shabbat v. 3 Sechita Bshaar Dvarim 320:25)
- Shemirat Shabbat KeHilchata 10:1
- Yalkut Yosef (Shabbat v. 3 Sechita Bshaar Dvarim 320:24). He references Lev Avraham 1:49 as also being lenient.
- Shemirat Shabbat KeHilchata 10:2
- Daily Halacha, Kaf Hachayim 320:60, Yalkut Yosef 320:27. Sh"t Lev Chaim 2:192 is stringent however.
- Shemirat Shabbat KeHilchata 10:3
- Shemirat Shabbat KeHilchata 1:74
- 39 Melachos (vol 2, pg 358)
- 39 Melachos (vol 2, pg 367), Yalkut Yosef 320:29
- Yalkut Yosef 320:30 in the footnote, Sh"t Az Nidberu 6:5 and 10:11
- Shemirat Shabbat KeHilchata 10:4 and 39 Melachos (vol 2, pg 370) write that one shouldn't make ice on Shabbat unless a need arises. A Guide to Practical Halacha (Shabbat v. 3 p. 155 n. 58) quoting Rav Moshe Feinstein agrees. Dovev Mesharim 1:55, Shevet Halevi 3:55, and Chelkat Yaakov 2:98 also say not to make ice on Shabbat.
- The Shabbos Kitchen 177 footnote 22 quotes Or Hashabbos 4:107 in the name of Rav Moshe Feinstein that you can make ice because it has no permanence. Mesoret Moshe v. 2 p. 66 also quotes Rav Moshe as holding that you can make ice on Shabbat. See also Tzitz Eliezer 6:34 and 8:12 as well as Minchat Yitzchak 8:24.
- Or Letzion 2:32:3, Rabbi Eli Mansour on dailyhalacha.com. Or Lezion explains that there's no nolad while changing the form of a liquid to solid or vice versa for Sephardim (SA O.C. 318:16).
- Shemirat Shabbat KeHilchata 10:5, 10:9
- Shemirat Shabbat KeHilchata 10:5, 10
- Shemirat Shabbat KeHilchata 10:8
- Shemirat Shabbat KeHilchata 8:9, 10:6
- Shemirat Shabbat KeHilchata 1:73
- 39 Melachos (vol 2, pg 371), Halachically Speaking (vol 4, Issue 16, pg 5) quoting Rav Yisrael Belsky (also in Shulchan Halevi 9:9), Shabbos Kitchen page 169 in the name of Rav Menashe Klein and Rav Moshe Stern.
- Rivevot Ephraim 8:158:11 quotes that Rav Chaim Pinchas Scheinberg, Rav Dovid Feinstein and Rav Yaakov Yisrael Fisher were lenient and allowed it. Rabbi Aharon Felder (Rishumei Ahron vol. 2 page 30, 321:3) writes that this was the opinion of Rav Moshe Feinstein. See Mesoret Moshe (v. 3 OC n. 190). Rav Daniel Mann quotes that Rav Mordechai Willig is lenient because the change from thick liquid to a foam isn't enough of a change to be considered molid. see Rabbi Aryeh Lebowitz for an elaboration.
- see Brushing Teeth on Shabbat
- see Electricity on Shabbat