LIGHTNING (pp. 313-315)

Strong ___________ and the collision of ___________ _____________ and ___________ _______________ in the clouds strip ___________________ from some particles and deposit them on others. Strong updrafts in the _______________ of the ___________________ carry smaller ____________ crystals and particles up while larger ones fall down. __________________ charges collect at the ________________ of the clouds whereas the higher, ________________ parts of the clouds are _________________ charged.

The negative charges on the ___________________ of the clouds repel _________________ on the surface of the ___________________, leaving the ground _________________ charged just below the cloud. This is an example of charging by ___________________ (contact? friction? induction?). The strong _____________________ between the __________________ cloud and the ____________________ ground pull ___________________ off atoms and molecules in the air. This occurs mostly over the _____________________ point on the ground.

A chain of ______________ forms and a gigantic ___________________ occurs between the _________________ and the ____________________. So many ___________________ crash through the air so fast, colliding with other _____________________, that the air both __________________up and __________________ up (ie. the temp. can reach ____________________ near a lightning bolt). The heat causes the air to __________________ rapidly. ______________ molecules colliding with other ____________ molecules produce a _____________ wave that we hear as _____________________. If the lightning hits a person, it can stop the ___________________ or _______________________.

The best way to control a lightning strike is to direct the flow of _______________ away from buildings and prevent fires. Electrons travel most easily through ___________________. ___________________ rods are based on this principle.

A lightning rod is charged by ___________________, just like the sphere on your ___________________. The _______________ charged lightning rod is the ____________________ point in the area. It attracts the ____________________ ions that have formed in the ______________, while the cloud attracts the ___________________ ions. A chain of ____________ thus forms between the cloud and the lightning rod. This chain acts as a ____________________ providing a path for the __________________ _________. When the lightning bolt strikes, it hits the ___________________ __________. The ____________________ are carried into the _________________ by a heavy conductor, often made of braided ________________.

Although the light from lightning travels so fast it almost takes no time to reach us. But the sound from the thunder takes about __________ seconds to travel one _________________. Imagine you heard thunder six seconds after you saw a lightning flash. How far are you from the lightning bolt? ___________ km.

- Draw Fig. 9.14 (pg. 314)