Audio-visual aids in the classroom might seem a fairly modern innovation, but a look at the Torah in general, and the Haggadah in particular, will bring us once to conclude again that "there's nothing new under the sun."  As a case in point, let's look at the ceremonies of the Seder night.

From start to finish, the Seder is designed to accomplish one purpose: to arouse the children's interest and get them to ask questions.  On the Seder night, we instill faith in their hearts by reliving together with them the myriad miracles of the Exodus.  The evening's rituals reinforce our own, and our children's awareness of the Creator as omniscient and omnipotent, caring, consistent, tireless, and indefeasible in His administration of this world.

The Torah places much emphasis on visual impressions.  We find the words "You have seen (such and such)" said to Israel several times. 

And the L-rd said unto Moses: Thus shall you say unto the Children of Israel: You yourselves have seen that I have spoken with you from heaven.  (Exodus 20:18)

You have seen what I did to the Egyptians, and how I bore you on eagles' wings, and brought you unto Myself.  Now therefore, if you will hearken unto My voice indeed, and keep My covenant, then you shall be Mine own treasure from among all peoples; for all the earth is Mine; (Exodus 19:4) 

...You have seen all that the L-rd did before your eyes in the land of Egypt unto Pharaoh, and unto all his servants, and unto all his land, the great trials which your eyes saw, the signs and those great wonders... (Deuteronomy 29:1-2)

The Torah is referring to both the miracles of the Exodus and to the wonders of the Revelation at Mount Sinai.  In both cases, the events were witnessed by millions of people, a fact which rules out any possibility that the records of these events are not historically valid. The fact that these events were witnessed by the entire nation is stressed to the People of Israel repeatedly, because this fact is the basis of their obligation to continue to pass on to the next generation the torch of faith which they ignited at Sinai.

The first case of a visual aid that we find in the Bible occurs as early as the story of Noah.  After the Flood, G-d set a rainbow in the heavens as a reminder to the generations to come that He had taken an oath never again to destroy the entire world with water:

And I will establish My covenant with you ...neither shall there ever be another flood to destroy the earth.' And G-d said: 'This is the token of the covenant which I make between Me and you and every living creature that is with you, for perpetual generations:  I have set My bow in the cloud, and it shall be for a token of a covenant between Me and the earth. And it shall come to pass, when I bring clouds over the earth, and the bow is seen in the cloud, that I will remember My covenant, which is between Me and you and every living creature of all flesh; and the waters shall no more become a flood to destroy all flesh. (Genesis 9:17)

G-d established the rainbow as the symbol of His promise never again to destroy the world by flood.  Ever since, each time a Jew sees a rainbow, he recites a blessing over it:

"Blessed are You, G-d, our L-rd, King of the Universe, who remembers the covenant, who is trustworthy in His covenant, and who keeps His word."

Another symbol is the covenant of circumcision, a permanent sign of our ongoing bond with our Creator, and the obligations that we, as a nation, have to carry out the commitments we undertook with the "signing" of this "pact with G-d."

Another example of symbolism in the Bible is tephillin, the phylacteries worn on weekdays by the Jewish male.

Then our Sages discussed what methods parents should use in order to pass the story of the Exodus on to their offspring, they followed the examples they found in the Torah.  One needs to describe, and to make the events come to life, to add explanations suited to the child's age and temperament, so that their faith will be concrete and unshakable.

The task of reliving the Exodus on the Seder night does not start with the children.  The father must start with himself, the mother with herself.  This, indeed, is in keeping with the dictum of our Sages: "In every generation, one is obliged to look at himself as though he, personally, went forth from Egypt."

In other words, he or she must relive the Exodus, not just speak about it.  When he himself has tasted the experiences of the liberation from Egypt, as though he had been there, he has what to share with his children and children's children.  Now he is equipped to fulfill the Torah's injunction: "You shall tell your child..."

All the rituals and ceremonies and customs established by our Sages, whether specific to one particular Jewish community, or universally observed by Jews everywhere, are intended for one and the same purpose: to help us internalize the experiences of the exodus and make them a part of our personality and that of our children.

Thus we renew and deepen our faith each year, and pass it on to our children and their children, the future hope of all Israel.