In the summer of 5743 (1983) the Rebbe (the 7th Grand Rabbi of Chabad) urged that in all schools a moment of silence should be instituted, at the beginning of every day. These sixty seconds should be designated to thinking about the Creator and Director of the world, and about performing the universal Sheva Mitzvos Bnei Noach. Heeding the Rebbe's call, the President of that time signed a call for the moment of silence. The Rebbe acclaimed this act of the President and wished that all Senators and Congressmen would follow suit. In the coming years the President's call was accepted in many states of America.
Many questions were raised concerning this idea and the Rebbe addressed and dealt with each of them during the farbrengens in the following years, explaining at length the reasoning and the purpose behind this campaign.
At one farbrengen the Rebbe explained:
The only way to guarantee that people should follow the straight and just path is to instill in them a faith in the Creator of the world.
In this country many parents do not have the time or patience to educate their children. They discharge their obligation by sending them off to school with tasty sandwiches, giving them spending money for treats, and nice clothing, of course. Education they leave for the school.
And for absurd reasons, mentioning the Creator and Conductor of the world is not allowed in school! As a result, hundreds of thousands of Jewish children and millions of non-Jewish children who are enrolled in public schools do not hear or know anything about the Creator! The only solution to this is to institute a moment of silence at the beginning of the school day, which is designated to thinking about the Creator. This, the Rebbe assured the critics, would influence the rest of the day.
Furthermore, even if children receive the best education at school, it is important that they hear these messages at home as well. As a result of the Moment of Silence children will ask their parents what they are meant to think about at that time, and this question will remind the parents of their role in educating their children.
(תו"מ תשד"מ ח"ד ע' 2172 ובכ"מ)
The Rebbe made it clear that the Moment of Silence is not a lifeless silence, but rather a purposeful meditation - that the Creator of the world also directs it in every detail. And His involvement includes the child himself, his parents and his friends.
(תו"מ תשמ"ו ח"ד ע' 265)
via Lma’an Yishme’u