We're not permitted to work on the Shabbat (Exodus ch.20). This includes 39 categories (Talmud, Shabbat 73b) of productive interaction with the world, such as planting, writing, building, kindling fire, using electricity, etc.
In Jewish law, the act of creating a spark by turning on a light is considered lighting a fire, which is prohibited on Shabbat. Observant Jews refrain from using electricity or turning on lights during Shabbat to adhere to this prohibition.
They prepare their children for Shabbat and light the Shabbat candles.
"Shabbat Shalom!"
They're called Shabbat candles (Neirot Shabbat in Hebrew).
Shabbat Shabbatot
After Shabbat, there is the Havdalah service.
Shabbat comes from the Hebrew word for sit/rest. Shabbat is the day of rest.
Shabbat Shalom (שבת שלום).Note: This means 'A peaceful shabbat'. The phrase "happy shabbat" is not a phrase that is traditionally used.
Shabbat shalom is a Jewish greeting which we say during the day of Shabbat. See also:More about the Jewish Shabbat
There is no issue with swimming during Shabbat, however, you wouldn't be able to shower after swimming until Shabbat ends. (Assuming you wish to be Shabbat observant.)
Judaism.See also:More about Shabbat
They say Shabbat blessings for their children.