during "lail hasheder" which is the first night of pesach (passover) it is common practice to fill up a large, usually silver, for Elijah the prophit who is said to visit every house hold during that night and take a sip from his cup. one also opens the door for him. beyond being a weird custom it is simbolic of the open door attitude meaning all who are in need are welcome to join those who have and it is considered a great deed to host a needing person at such times.
There is no establish tradition of having an empty chair at a seder. There are some groups today who have an empty chair at the table in honour of friends and/or family who have been killed in war or who are in the military and cannot be present at the seder. The actual tradition is to have a full glass of wine on the table during the seder. This cup is for the prophet Eliyahu who is said will arrive before HaMoshiach does to anounce his arrival and anoint him.
The purpose of this is to open the door for Elijah, a prophet who is given a cup of wine at the table as well.
You drink the first cup after saying Kiddush in the beginning of the seder. You drink the second cup after saying Hallelujah and before the washing of the hands (Rahatz) Then you drink the third cup before Hallel and at this point, the Cup of Elijah is filled. Finally, the fourth cup is to be drank right before the acceptance of the divine service or Nirtza.
The 4 glasses of red wine at the seder symbolise HaShem's four statements of redemption in the Torah: 1. "I took you out" 2. "I rescued you" 3. "I liberated you" 4. "I took you to Me for a people" The wine represents redemption while the colour of the red wine reminds us of the blood of the children killed for the Pharaoh.
The reaction force when you place a cup on a table is the force exerted by the table on the cup in the opposite direction to the force applied by the cup on the table. This force prevents the cup from falling through the table and keeps it in place.
The different glasses of wine drunk during the seder do not have specific names.
When a cup is placed on a table, the table exerts an equal and opposite reaction force on the cup to support its weight.
A table spoon is smaller than a cup, therefore; it's not possible to fit a cup into a table spoon, but there are 16 table spoons in a cup. 1/16 cup
Moses and Eliyahu (Elijah) are each mentioned once in the Passover Haggadah. Symbolically, Eliyahu comes to the Seder and we prepare a cup in his honor. He symbolizes the future redemption (Malachi ch.3). See:More about the Seder
1 cup = 16 tablespoons
The cup sitting on a table has potential energy due to its position above the ground. When lifted, work is done on the cup against gravity, storing potential energy in the cup-table system. This potential energy can be released if the cup is allowed to fall.
The answer to "how many table spoons is in a cup?" is 16........The answer to "how many table spoons is in a cup?" is 16........The answer to "how many table spoons is in a cup?" is 16........