Thunder and lightning

Presentation by:Alphonsa JosephSocial ScienceReg.No: 16914302003

Direction for Computer Assisted lessonFollow the Instruction given below:This lesson is about the topic- Thunder and Lightning.

This capsule contain suitable slides related to the concept. Relevant Pictures are provided in each slide. Use mouse (single click) to move to the next slide. Click on the textbox to get the response.Please note the direction given by the computer.Brain Teasers are provided for developing conceptsBrain relaxers are provided for self checking aided with necessary explanation.After completing the lesson , the learners can recapitulate the lesson through ‘Test Your knowledge’ session.

What is Lightning and Thunder-Video clipping

THUNDERSTORMS ??

A thunderstorm is a storm with lightning and thunder. It is produced by a cumulonimbus cloud, usually producing gusty winds, heavy rain and sometimes hail.

Let us observe the pictures and identify the ingredients of thunderstorm

THUNDERSTORM INGREDIENTS

Moisture - Preferably in the lower or mid levels of the atmosphere

Upper level just stream can carry pockets of cold air over moist air, increasing lift and instability

THUNDERSTORM INGREDIENTS

Source of lift – Agent which lifts the warm, moist air at the starting of the thunderstorm

THUNDERSTORM INGREDIENTS

Instability – Ability for air to accelerate upward/downward when started up/down

Look at the fig. 5 in which different life cycles are involved in the thunderstorm. From the figure , identify the cycles of a thunderstorm

THUNDERSTORM LIFE CYCLE

Cumulus Stage Mature Stage Dissipating Stage

Fig.5

The life cycle of thunderstorm are in three ways:

Cumulus stage Mature stage Dissipating stage

What is that bright flash of light that shoots across the sky during a storm?

It’s lightning, and it’s an enormous electrical discharge that occurs in the atmosphere during thunderstorms.

But what exactly causes this electricity in the sky?

LIGHTNING

In the process of the water cycle, moisture can accumulate in the atmosphere. This accumulation is what we see as a cloud

Cloud droplets collide other moisture, that is in the process of condensing as it rises.

STEP 1

The importance of these collisions is that electrons are knocked off of the rising moisture

The newly knocked-off electrons gather at the lower portion of the cloud, giving it a negative charge

Step 2

LIGHTNING FORMATION

THUNDER

As the rising moisture encounters colder temperatures in the upper cloud regions and begins to freeze, the frozen portion becomes negatively charged and the unfrozen droplets become positively charged.

Here, rising air currents have the ability to remove the positively charged droplets from the ice and carry them to the top of the cloud.

The cloud then becomes separated by charges

It becomes positively charged at the top and negative at the bottom creating an electric field.

STEP 4

The electric field becomes so large, that it can rip some of the electrons of the air molecules, you then get some electrons and positive ions - a plasma.

As there are free electrons and positive ions, this plasma conducts electricity very well unlike air which is a good insulator, and electricity will follow the easiest path, so all the charge from a significant portion of a cloud will follow this path, creating a huge spark - a lightning bolt.

The entire process of a lightning bolt occurs in a matter of seconds

SAVING YOUSELF FROM THUDERSTORMS.

•If you find yourself caught in a lightning storm, the key to minimizing danger is to get inside and could protect structure. If you can detect lightning, it may be close enough to strike you. •Never stand under a tall or short tree, and avoid being close to power lines as they’re both excellent conductors of electricity and could potentially cause death. If not serious injury. •Find shelter near or under a stony shelter, say a cavern or something,. Never stay near windows. Don’t touch electric oriental surfaces

DEFINING THE TERM – THUNDER

THUNDER STORMS ARE PRODUCED BY CUMULONIMBUS CLOUDS AND ARE ACCOMPANIED BY LIGHTNING AND THUNDER.

It Occurs when the atmosphere becomes unstable—when a vertically displaced air parcel becomes buoyant and rises on its own.The ideal conditions include warm, moist air near the surface and a large change in temperature with height (large lapse rate)

Brain Teaser 1.1 Thunder storms occur when the atmosphere is stable and calm?

Yes NoRefer brain relaxer 1.1 Click

here

WrongAnswer

CORRECTANSWER

The thunderstorm happens when the

atmosphere is unstable and the conditions of

warm, moist air near the surface and a large

change in temperature with height

Thunderstorm Hazards

Lightning

Tornadoes/downbursts

Hail

Flash Floods

It was the mid of July. I was sprawled on my comfortable bed and watching a movie, when my mother came in and asked me to get ready to go shopping; she wanted to collect her bangles from the jewellers. She said that she wanted to come back before Maghrib.

Fifteen minutes later, we were on the road. The sky had been cloudy since morning. As it began to drizzle, I became more conscious on the road. I had been driving fast, so I slowed down to avoid risks. The drizzle changed to sudden downpour as we neared the shop. People on the road started to run frantically for shelter. Vehicles slowed down on the road as well.

Suddenly, we heard a very loud crack of thunder followed by a bright flash of lightning outside my car window. Within a few minutes, roads and streets had turned into streams and rivers. Many trees were uprooted. The storm plunged the city into darkness. Advertisement boards began to fall and damage vehicles around them

.

A story of thunderstorm hazards

Every year 100-200 people die from lightning strikes

There are actually nine cloud-to-cloud strokes for each cloud-to-ground stroke

Cloud-to-Ground strokes are the most dangerous.

Notice the segmented pathway to the ground. Also, some of the lighting didn’t contact the ground.

Lightning doesn’t always hit the tallest object…

Out on the golf course is NOT a safe place during a thunderstorm.

Here are some pictures of thunderstorm hazards. Observe the pictures and identify what kind of hazards happen due to thunderstorm

All thunderstorms are dangerous and can be associated with a number of hazards. Heavy rains can lead to flash flooding events ,one of the primary causes of death associated with thunderstorms. 

Lightning, which is produced by every thunderstorm, causes an average of 80 fatalities and 300 injuries each year.

ENLARGING THE DEFINITION

The thunderstorms and its effects like lightning, flooding, hail etc are dangerous hazards to human beings

Thunderstorms cause many hazards

to humans

D5

Brain Teaser 2.2Do thunderstorms cause destruction of buildings or houses?

Yes No

Refer Brain Relaxer 2.2

Click here

WRONG ANSWER

Try again

CORRECT ANSWER

Thunderstorms and lighting are natural hazards which cause

heavy damage to human beings

DEFINITION

Thunderstorms are the factor behind lightning, flooding, hail and downbursts

D6

CONCEPT FORMATION

C2 Thunderstorms are natural hazards which emerge due to the instability of atmosphere and cause heavy damage to human life

UNIT 1Thunder and lightning

THINKING SESSION

Brain Relaxer 2.1Read the newsTHE HINDU-April 23, 2015 Bihar thunderstorm kills 42Crops damaged in north-eastern border districts

At least 42 people were killed, more than 100 injured and crops damaged when a thunderstorm hit the north-eastern border districts of Bihar late on Tuesday night.

“It was a strong storm with a wind speed of more than 150 kmph. Purnia is the worst-affected district, with the most people killed,” Chief Minister Nitish Kumar told presspersons here after an aerial survey of the affected areas. Officials said the death toll was likely to rise.

Mr. Kumar said the final assessment of damage would be possible only after officials of the affected districts sent in the details.

From the above news it is clear

that the lightning and thunderstorm are hazardous to

human life

Brain Relaxer 2.2

Look at the picture

Fig.3

REHABILITATION AFTER THUNDERSTORM

After the thunderstorm and its hazards, the people need rehabilitation as they lost their

belongings

Test your knowledgeI Say True or False

1. Thunderstorm and lightning are hazardous to human life

2. Thunderstorms have various life cylcles

3. What are the various hazards caused by thunderstorm? Answer …………………………………………………………………………. ………………………………………………………………………….

True False

True False

Wrong Answer

Correct

Answer Key

a. Floodingb. Lightningc. Haild. Downbursts