3. WHAT CAUSES LIGHTNING?
o In a thunderstorm, clouds are a collection of drips of moisture condensed
around tiny particles floating in the air.
o These particles fly around and bump into each other. As this happens, the
atoms bounce electrons off one another and build up electrical charges
(ionization).
o When this build up reaches a certain level, the electrons start to reach out to
the ground, looking to connect and equalize the charge separation of the
negatively charged cloud and positively charged earth. These invisible paths of
reaching electrons are called step leaders.
o Electrons on the ground are reaching out, too.* These send streamers of
positive energy. Streamers come from anything on earth, including people.
o When the two opposite charges connect, the cloud discharges electrons into
whichever streamer that meets the first step leader, creating lightning
o Positive energy flies up to the cloud from the earth to equalize the charge and
the negative energy comes down. This happens repeatedly and quickly.
o The flash we see isn‟t electricity, but an explosion of heat, because these
moving electrons get extremely hot, causing the air around the bolt to explode.*
4. WHAT CAUSES VOLCANIC LIGHTNING?
o
o
First major study of volcanic lightning was in 1963, Iceland.*
50 years since, the most significant study was published in 2007*.
o
The 2007 study corroborates what was found in the 1963 study – that volcanic lightning is
also caused by the same charge separation that causes regular lightning.
o
Scientists can only theorize what causes the charge separation. They assume large clouds
and fast moving exploding rocks create a similar electrical charge to a thundercloud. The
aerodynamics of positively charged rocks and magma flying into negatively charged clouds
of ash and dust over and over again causes chaotic levels of rapidly evolving charge
separation. The step leaders and streamers meet over and over again.
o
Further studies in 2007 have led to the conclusion that there are at least two types of
volcanic lightning – one that occurs at the mouth of an erupting volcano, and a second that
dances around in the heights of the towering plume.
o
Question of where the charges come from – unsure of whether it comes out of the volcano
or if it is created just afterwards.
o
The team from the 2007 study suggests that magma, rock and volcanic ash, jettisoned
during an eruption, are themselves electrically charged by some previous, unknown
process.
o
Another holds that highly energized air and gas, upon colliding with cooler particles in the
atmosphere, generate branched lightning high above the volcano's peak.
o
Other hypotheses, still, implicate rising water and ice-coated ash particles.
6. MIRAGE
WHAT IT IS:
o “Mirage” is borrowed from the French language and its root word is “mirari” which
is Latin for “to look”, “to wonder”
o A mirage is an optical phenomenon that occurs naturally
any observable event that results from the interaction
of light and matter
o
When we see a mirage, we are actually seeing a reflection of the sky on the ground.
o
THE SCIENCE BEHIND IT:
Our brains are used to interpreting light coming to us in straight lines. This is not
always the case: Light rays can experience refraction (they can be bent while passing
through one medium to the other)
Refraction occurs because light travels at different speeds through hot air and cold
air.
Temperature has an effect on air and its density. Cold air is denser than warm air, and
therefore it has a higher refractive index. This means that light will be bent more as it
passes through a medium with a higher index.
The particles of light (also known as photons) bump into more matter in a more dense
material which slows them down, and the ray of light therefore bends.
As light passes from a LOW index to a HIGH index, the light bends towards the
normal (a line perpendicular to the medium boundary). When light travels from a
HIGH index to a LOW index, the light bends away from the normal.
7. WHAT HAPPENS:
We now know that a mirage is created when light rays pass from colder air to the much
hotter air near the ground. On a sunny day, the air directly above a road is warmer than
the air above it. This is because the hot ground warms a layer of air just above the
ground.
A layer of very warm air near the ground refracts the light from the sky nearly into a Ushaped bend. Our brain thinks the light has travelled in a straight line.
If the temperature change is significant enough, the light from the sky can be refracted
by the hotter air before it hits the ground.
Since our brain assumes that light follows a straight path, we follow the refracted light
back to the source, which appears to be the ground. We think we have stumbled on an
oasis when in reality we are seeing a shimmering image of the blue sky.
8.
Inferior mirages (such as the one I have explained) occur when there is strong
heating at ground level. With superior mirages, colder temperatures can have a
distinct (and almost opposite) effect which result in myths such as sailors seeing
ships floating in the sky.
With cold (dense) air near the surface and warm (less dense) air just above, an
atmospheric lens is formed that can bend light
This refraction results in making things look higher or taller than they actually
are: a superior mirage.
Occasionally, objects get reversed and distorted as well.
10. DEW DROPS
o
Water droplets
o
Formation due to condensation
o
Frost-dew in the form of ice
o
Difference between Dew and Guttation
o
Dew point
o
Preferable weather conditions
o
Dewfall and distillation
11. o
o
o
o
o
o
o
Drosometer – measuring instrument
Dependence on radiation balance
Range of Dew amount/ night – up to 0.8 mm
Habitat for Fungus (Potato)
Dew catching devices
International Organization for Dew Utilization
Indian Institute of Management Sciences- Large
Scale Dew harvesting System
13. •Also known as ambulation
•Means: „to roll‟
•Difference between running and walking:
Walking
With each step
Running
One foot at a times Both feet are off
leaves contact with the ground.
the ground.
•Walking Speed:
•depends upon the following factors;
-height
-weight
-surface
-culture
-age
-terrain
-load
-effort and fitness
•average speed: 5.0km/h
•average human child achieves independent walking ability at around 11 months old.
•Anatomy of walk:
•Complex
•not only feet have to move across the
ground but hips, spine, arms, shoulders
and head all move in sync to maintain
balance in system.
14. Feet and Legs:
-both propel the body forward.
1
2
3
1-Starts with
feet furthest
apart.
-Weight
shifts to
forward foot.
2-Knee bends to
absorb shock.
-Recoil position.
-Lowest point.
4
5
3-Halfway through
first step.
-Foot passes
supporting leg;
passing position.
-Character moves;
knee straightens;
lifts body; highest
point.
4-Character moves;
weight bearing foot
leaves off through
heels; force
transmitted to foot‟s
ball.
-Body falls forward.
-Free foot swings
forward to catch
ground.
5-Half cycle
completes.
-Second half is
exact mirror of
first half.
16. RAINBOW
One of the most splendid color shows observed on
the earth caused by the reflection and refraction of
light in water droplets in earth‟s atmosphere.
Sun is always behind your face when you observe
rainbow. Rainbows are not only formed after rain,
but also on mist, spray, and airborne dew.
The color band comprises of red, orange, yellow,
green, blue, indigo, violet.
Types of rainbow:
1.
Primary rainbow
2.
Secondary rainbow
17. TYPES OF RAINBOW
Primary rainbow
It is generated when white
light makes ONE internal
reflection in the drop.
Colors are more clear.
In this type red in on outer
arc and violet on the inner
arc.
Secondary rainbow
It is generated when sunlight
makes TWO internal
reflections in the drop
instead of one.
It is weaker/faint than
primary rainbow because
intensity of light reduced in
the second refraction.
Colors are reversed. Violet
is on the outer arc and red in
the inner arc.
1 billion volts of electricity in a bolt of lightning and lightning occurs around the world one hundred times every second. A bolt of lightning is essentially nature’s way of balancing charge distribution. *Like when you rub your hair with a balloon and pull away, your hair stands up and reaches for the balloon, caused by att*causing thunder.
People have been witnessing these for the past 2000 years. Earliest written account comes from a man in Pompei. Few studies because of the obvious danger that comes with studying volcanoes. *Surtsey eruption.*Mount Augstine eruption, 2006.
Inferior mirages (such as the one I have explained) occur when there is strong heating at ground level. With superior mirages, colder temperatures can have a distinct effect which result in myths such as sailors seeing ships floating in the sky. So, does anyone have a question?
Each individual droplet acts like tiny prism that disperses the light and reflects it back to ur eye. This refraction makes different wavelengths, or colors, of the white light from the sun to separate.
