Lightning2/11/14

Bellwork

What are the three ways to charge an object?

• Friction

• Contact

• Induction

Video

• http://videos.howstuffworks.com/discovery/406-discovery-wonders-of-weather-lightning-phenomena-video.htm

Lightning• Charge separation within the cloud

• Positive charges at the top of the cloud

• Negative charges at the bottom of the cloud

• Clouds charge the ground by induction

• Step Leaders – come from the cloud (many kilometers long)

• Streamers – form from ground objects (only meters long)

Types of Lightning

• Intra-Cloud (~80%)

• Cloud to Ground (~20%)

–Negative (18%)

–Positive (2%)

• Cloud to Cloud and Cloud to Air (rare)

Negative vs. Positive Lightning

• Negative Lightning • Positive lightning

Negative and Cloud to Cloud Lightning

Negative Lightning

Intra-Cloud Lightning

Positive Lightning

The Sound of Thunder

• Lightning heats up the air quickly (30,000 K) causing the air to rapidly expand.

• This is the sound that we hear.

Lightning Videos

• http://www.youtube.com/watch?v=dukkO7c2eUE (slow motion)

• http://www.youtube.com/watch?v=8waV48897o4 (slow motion)

• http://www.youtube.com/watch?v=RDDfkKEa2ls (upwa

• http://www.youtube.com/watch?v=kYguAFZwhpUrd lightning)

End of Notes

• Alternative Pictures Follow