Chào các thính giả yêu mến của chương trình Học Tiếng Anh qua các chủ đề của chương trình học tiếng anh cùng Radiome. Mình là Diệu Hoa.
Hôm nay chúng ta cùng theo dõi tiếp Phần 2 của bài nghe Lightning and Electricity nhé!
Các bạn cùng chú ý lắng nghe với tiết tấu chậm rãi của chương trình Spotlight nhé. Note lại những từ bạn nghe chưa rõ và xem lại ở bản text để làm phong phú thêm vốn từ vựng của mình nhé!

Voice 2 
No matter who is right about the details of the experiment, Franklin’s theory still caused many people to investigate lightning. Now, scientists agree that lightning is electricity. And scientists know much more about lightning. They tell us that:
Voice 1 
On average, there are 100 lightning strikes every second around the world.
Voice 2 
Lightning can send out a million volts of electricity! The temperature in a lightning bolt is about 30,000 degrees Celsius.
Voice 1 
Lightning can strike in half a second. In that time, the lightning heats the surrounding air. It heats it to an extremely high temperature - five times hotter than that on the sun’s surface! The heat causes the air to expand. This makes a sound. We hear this sound as thunder. Although this happens at the same time, we hear the thunder after the lightning. The reason for this is simply because sound travels more slowly than light.
Voice 2 
Lightning disappears quickly in the air. But it does sometimes leave something behind: fulgurites. The word comes from the Latin word for lightning, ‘fulgur’. The best-known fulgurites are sand fulgurites. These are found under the surface of sand.

Voice 1 
Sand fulgurites form when lightning hits sand. They are thin glass tubes under the sand. The heat from the electrical current is very intense. It melts the sand into glass. Fulgurites usually take the shape of the roots of a tree. The outside of the thin tubes is silica glass. Scientists can easily make silica glass in laboratories. But it is very rare to find it in nature. Fulgurites are not usually longer than a few centimetres. This is because movement of the sand often breaks the fine tubes. They are after all, glass.
Voice 2 
Rock fulgurites form in a similar way. They form when lightning strikes the surface of rock. The lightning melts the rock’s surface. It can also melt the inner part of the rock. Rock fulgurites are even less common than sand fulgurites.
Voice 1
The formation of fulgurites shows just how powerful lightning is. Lightning can cause great damage to buildings - especially tall buildings. Benjamin Franklin invented something simple to prevent this damage. His invention is called a lightning rod. Lightning rods are tall thin pieces of metal. A rod may have a pointed end, or a ball at the end. People place lightning rods at the top of a building. The rod is the tallest thing on the building. A wire goes from the rod to the ground. When lightning strikes, the electricity goes through the rod to the ground. The lightning does not affect the building. Lightning rods became very popular because of Franklin. They have saved many buildings!
Voice 2 
From electricity to a lightning rod that saves buildings. Benjamin Franklin asked questions. He changed ideas. And he invented something that still helps people today! All discoveries start in the same place. What questions do you have? What can you create?
Voice 1 
The writers of this program were Marina Santee and Christy VanArragon. The producer was Nick Mangeolles. The voices you heard were from the United Kingdom and the United States. All quotes were adapted for this program and voiced by Spotlight. You can listen to this program again, and read it, on the internet at www.radioenglish.net. This program is called, ‘Lightning and Electricity’.
Voice 2 
You can also leave your comments on our website. Or you can email us at radio@radioenglish.net. You can also find us on Facebook - just search for spotlightradio. We hope you can join us again for the next Spotlight program. Goodbye.
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