EnglishClub

Pre-listening vocabulary

• dwarf: a type of star that is small and faint
• celestial: relating to space
• classify: to sort something into a category
• compress: to make something smaller and more dense
• core: the centre of a planet or star
• fuse: to combine things together
• deuterium: a variation of hydrogen

Listening activity

Podcast: Play in new window | Download (Duration: 1:25 — 1.3MB)

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Gapfill exercise

A brown dwarf is a type of celestial object that can’t be classified as a or a star. Although brown dwarfs look more like planets, they form the same way stars do. A star is created when a of gas and dust begins to compress. The intense force of causes the star’s core to fuse atoms together, producing helium. Fusion is what causes a star to shine. Early in its life, a star fuses atoms of deuterium. It begins to use regular hydrogen as its core gets hotter. However, brown dwarfs never reach this stage. They stay at low and fuse deuterium until they run out. Brown dwarfs produce very little , which makes them hard to find. Scientists first theorized about brown dwarfs in 1963, but didn’t observe any until 1995. 

Comprehension questions

1. Brown dwarfs look like
   a. planets
   b. stars
   c. asteroids
   
2. Brown dwarfs are different from stars because
   a. they use deuterium for fusion
   b. they don’t have cores
   c. they reach extremely high temperatures
   
3. It is difficult to find brown dwarfs because
   a. they don’t orbit anything
   b. they are smaller than most planets
   c. they emit very little light

See answers below

Discussion/essay questions

1. Scientists are always learning more about space. What do you think will be discovered in the future?

Transcript

A brown dwarf is a type of celestial object that can’t be classified as a planet or a star. Although brown dwarfs look more like planets, they form the same way stars do. A star is created when a cloud of gas and dust begins to compress. The intense force of gravity causes the star’s core to fuse atoms together, producing helium. Fusion is what causes a star to shine. Early in its life, a star fuses atoms of deuterium. It begins to use regular hydrogen as its core gets hotter. However, brown dwarfs never reach this stage. They stay at low temperatures and fuse deuterium until they run out. Brown dwarfs produce very little light, which makes them hard to find. Scientists first theorized about brown dwarfs in 1963, but didn’t observe any until 1995. 

Answers to comprehension questions

1a 2a 3c

Pre-listening vocabulary

• reaction: a process where a substance undergoes a change
• nucleus: the central part of an atom
• electron: a small charged particle that moves around the outside of an atom
• convert: to change something into something else
• fuse: to join together
• hydrogen: the lightest chemical element
• replicate: to recreate something

Listening activity

Podcast: Play in new window | Download (Duration: 1:16 — 1.2MB)

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Gapfill exercise

Nuclear fusion is a type of reaction that turns one chemical element into another. The Sun and other use nuclear fusion as a form of power. In high enough , the nucleus of an atom can be separated from its electrons. The heat causes the nucleus to move very quickly. When two nuclei come close enough to each other, they fuse, forming a larger nucleus. This method allows stars to convert hydrogen atoms into helium atoms, and even more atoms after that. Nuclear fusion is a difficult to replicate on Earth, because it requires a lot of heat and pressure. However, many research groups around the world hope to find a way to use it as an source.

Comprehension questions

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Discussion/essay questions

1. Scientists are interested in nuclear fusion because it would be a clean and powerful energy source. Unlike the type of nuclear power we use today, nuclear fusion would not create dangerous waste. Can you think of any potential disadvantages to this type of energy?

Transcript

Nuclear fusion is a type of reaction that turns one chemical element into another. The Sun and other stars use nuclear fusion as a form of power. In high enough temperatures, the nucleus of an atom can be separated from its electrons. The heat causes the nucleus to move very quickly. When two nuclei come close enough to each other, they fuse, forming a larger nucleus. This method allows stars to convert hydrogen atoms into helium atoms, and even more complex atoms after that. Nuclear fusion is a difficult process to replicate on Earth, because it requires a lot of heat and pressure. However, many research groups around the world hope to find a way to use it as an energy source.