Sound waves are mechanical waves. They can travel only through matter. They cannot travel through empty space. This was demonstrated in the 1600s by a scientist named Robert Boyle. Boyle placed a ticking clock in a sealed glass jar. The clock could be heard ticking through the air and glass of the jar. Then Boyle pumped the air out of the jar. The clock was still running, but the ticking could not be heard. Thats because the sound couldnt travel without air particles to transfer the sound energy. Is there any other place where sound cannot be heard? Here is a hint: is there any other place that does not have air molecules? Thats right, in space sound cannot be transferred. So can astronauts hear each other? Yes, they can, because they are in enclosed space stations or pressurized suits.In both cases, they are surrounded by air molecules. If they left their space ship and did not use their electronics, they would not be able to hear each other. Next time you watch a science fiction movie, think about this factoid. When spaceships are destroyed by hostile alien beings, there would be no sound heard. Sound waves can travel through many kinds of matter.

How do astronauts hear?

Alexander II's death caused a great setback for the reform movement. One of his last ideas was to draft plans for an elected parliament, or Duma, which were completed the day before he died but not yet released to the Russian people. In a matter of 48 hours, Alexander II planned to release his plan for the duma to the Russian people. Had he lived, Russia might have followed a path to constitutional monarchy instead of the long road of oppression that defined his successor's reign. The first action Alexander III took after his father's death was to tear up those plans. A Duma would not come into fruition until 1905, when Alexander II's grandson, Nicholas II, commissioned the Duma following extreme pressure on the monarchy as a result of the Russian Revolution of 1905. The assassination triggered major suppression of civil liberties in Russia, and police brutality burst back in full force after experiencing some restraint under the reign of Alexander II, whose death was witnessed first-hand by his son, Alexander III, and his grandson, Nicholas II, both future emperors who vowed not to have the same fate befall them. Both of them used the Okhrana to arrest protestors and uproot suspected rebel groups, creating further suppression of personal freedom for the Russian people. A series of anti-Jewish pogroms and antisemitic legislation, the May Laws, were yet another result. Finally, the tsar's assassination also inspired anarchists to advocate "'propaganda by deed'--the use of a spectacular act of violence to incite revolution." With construction starting in 1883, the Church of the Savior on Blood was built on the site of Alexander's assassination and dedicated in his memory.

What effect did Alexander II's death have on the Russian political climate?

Two women trade houses without ever having met . They 're both looking for an escape from their problems , but by running away , both come to discover a great deal about themselves . Ria Lynch is married to Danny Lynch and they have a daughter and a son . Danny begins spending less and less time at home with his wife and children . Ria believes another baby is the solution , and is shocked to find out that indeed her husband is going to be a father - but to a child from an affair he has been having . Her husband's unfaithfulness is the event that leads Ria into her decision to switch homes with a woman from the US called Marilyn who lost her teenage son to a motorcycle accident on his birthday . Marilyn is struggling to come to terms with her son's death and has become estranged from her husband . She hopes her time in Dublin will cease her grief . Ria and Marilyn discover deep , dark secrets about the other during the summer . The two become close friends but do not reveal the secrets . { { Expand section } }
What do the women discover while living in each other's houses?