By Kendra Wheeler

1
The Mystery of Lightning
By Kendra Wheeler LTEC 4100.031
2
TEKS Objectives

• 112.18 Science Grade 6
• (a) Introduction.
• (1) Science, as defined by the National Academy
  of Science, is the "use of evidence to construct
  testable explanations and predictions of natural
  phenomena, as well as the knowledge generated
  through this process." This vast body of changing
  and increasing knowledge is described by
  physical, mathematical, and conceptual models.
  Students should know that some questions are
  outside the realm of science because they deal
  with phenomena that are not scientifically
  testable.
• (4) The strands for Grade 6 include
• (A) Scientific investigations and
  reasoning.
• (b) Knowledge and skills
• (2) Scientific investigation and reasoning.
  The student uses scientific inquiry methods
  during laboratory and field investigations.
• (E) analyze data to formulate reasonable
  explanations, communicate valid conclusions
  supported by the data, and predict trends.

3
What Is Lightning?

• Lightning is an atmospheric discharge of
  electricity.
• It is the same kind of electricity that can
  happen when an object or person shocks you, which
  is commonly known as static electricity.
• The majority of lightning happens within the
  cloud or between the cloud and ground.

4
How Does it Work?

• Electrical charges produce inside of a storm
  cloud.
• The negative charges moves to the bottom of the
  cloud, while the positive charges moves to the
  top.
• When the area for the negative charge becomes
  crammed, then the atoms spring to another
  section of that cloud, or the ground, or even to
  different cloud.
• This spring causes a massive spark of static
  electricity that is known as lightning.

5
How Does It Work Contd

• When there is a huge charge separation in the
  electric area around the cloud, it will then
  begin to break down the air and cause the space
  that is sandwiched between the protons and
  electrons to expand in size. This method is known
  as ionizing the air.
• The ionization causes several paths that are
  known as step leaders. Their job is to find the
  easiest way to the opposite charge.
• As a place prepares for an electrical discharge,
  the positive area on the ground will send out a
  streamer that signals to the step leaders as
  being one that is positively charged and is an
  easy route.
• The last stage is the step leader and the
  streamer coming together, which is a complete
  path of ionized air connecting the ground and the
  cloud. When they two cross paths, it causes a
  current that is called the first return stroke.
  The first return stroke is the lightning that
  we see light up the sky.

6
Different Types of Lightning

• Cloud-to-Ground lightning
• is a discharge between a cumulonimbus
  cloud and the ground.
• Ground-to-cloud lightning
• is a discharge between the ground and a
  cumulonimbus cloud.
• Forked lightning
• is a type of cloud-to-ground lightning
  that displays branching.

7
Types Of Lightning Contd

• Ribbon lightning
• occurs in thunderstorms with high cross winds
  and multiple return strokes. The wind will blow
  each successive return stroke slightly to one
  side of the previous return stroke, causing a
  ribbon effect.
• Bead lightning
• is a type of cloud-to-ground lightning which
  seems to look as if it has broken up into a
  series of short, bright parts.
• Ball Lightning
• looks to be a glowing sphere that is recorded to
  be less than three feet wide and doesnt last
  more than a couple of minutes.

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Essential Question

• What are some of the different types of lightning
  and how does lightning form?

9
Unit Questions

• In a storm cloud, what type of charges are at the
  top and bottom of the cloud?
• What type of lightning is only three feet wide
  and only last for a couple of minutes?
• Where does the majority of lightning happen?
• When an object shocks a person, is that the same
  kind of electricity as lightning?

10
Fun Activities From D.E.

• Materials
• Group 1 ground pepper plastic utensil, such as
  a knife or a comb wool or nylon cloth
• Group 2 plastic comb, piece of wool or fur,
  metal doorknob
• Group 3 two rubber balloons
• Group 4 plastic combs, bowl of puffed rice
• Procedures
• Group 1
• Spread grains of ground pepper on a small area of
  a desktop.
• Vigorously rub a plastic utensil with a wool or
  nylon cloth to produce a negative charge.
• Hold the utensil about 1 inch over the mixture
  and observe what happens. (The utensil will pick
  up the pepper.)
• Group 2
• Darken the room as much as possible.
• Rub a plastic comb with a piece of wool or fur.
• Hold the comb near a metal doorknob.
• Observe what happens. (Students will see tiny
  sparks.)
• Group 3
• Blow up two balloons and rub them on your sleeve.
• Darken the room as much as possible.
• Rub the two balloons together.

11
Credits and References

• National Geographic -http//news.nationalgeographi
  c.com/news/2004/06/0623_040623_lightningfacts.html
  
• National Weather Service- http//www.lightningsafe
  ty.noaa.gov/more.htm
• 2003 Flight Forecast- http//www.centennialoffligh
  t.gov/2003FF/lightning/types.html
• TEKS- http//www.tea.state.tx.us/index2.aspx?id61
  48
• Discovery Education- http//school.discoveryeducat
  ion.com/lessonplans/programs/lightning/