L5-U3-P4-1 Listening : Electromagnetic Force

Electromagnetic Force

There are several fundamental forces that hold our universe together.

One of these, of course, is gravity, the force between objects that have mass.

Another important force is the electromagnetic force.

The electromagnetic force is responsible for chemical reactions.

Without it there would be no atoms or molecules.

Up until a couple of hundred years ago, very little was known about this force.

Learning about the electromagnetic force and how to use it was a major step forward.

It revolutionized communication, transportation and manufacturing.

Imagine what life would be like without electricity!

Learning about the electromagnetic force and how to use it was a major step forward.

(1) The electromagnetic force is responsible for chemical reactions.
(2) Without it there would be no atoms or molecules.
(3) Up until a couple of hundred years ago, very little was known about this force.
(4) Learning about the electromagnetic force and how to use it was a major step forward.

Which of the fundamental forces is between objects that have mass? -Gravity

(1) There are several fundamental forces that hold our universe together.
(2) One of these, of course, is gravity, the force between objects that have mass.
(3) Another important force is the electromagnetic force.
(4) The electromagnetic force is responsible for chemical reactions.

The electromagnetic force has two parts, the electrical force and the magnetic force.

The electric force is the force between electrically charged particles such as electrons and protons.

Electric charges attract or repel each other with a force that depends on the distance between them.

The magnetic force is the force between magnetic poles, such as the north and south pole.

In fact, the Earth is like a large bar magnet, with a north and a south pole.

Many animals use the Earth's magnetic field to navigate during their migrations.

We can also see this magnetic field when we use a compass.

Why is the earth like a large bar magnet? - It has a north and a south pole.

Many animals use the Earth's magnetic field to navigate during their migrations.

Another important force is the electromagnetic force.

We can also see this magnetic field when we use a compass.

There are several fundamental forces that hold our universe together.

Electric charges attract or repel each other with a force that depends on the distance between them.

For what purpose do many animals use the Earth's magnetic field? - for navigation

Electrons and protons are examples of what? -electrically charged particles

Imagine what life would be like without electricity!

In fact, the Earth is like a large barmagnet, with a north and a south pole.

There are several fundamental forces that hold our universe together.

The magnetic force is the force between magnetic poles, such as the north and south pole.

Why does the Earth have a magnetic field?

Many scientists believe that the Earth's magnetic field is due to the Earth's rotation.

Deep inside the Earth is a solid iron core, surrounded by a liquid metal outer core.

The moving electric currents inside this liquid metal create a magnetic field.

Deep inside the Earth is a solid iron core, surrounded by a liquid metal outer core. The moving electric currents inside this liquid metal create a magnetic field.

What is deep inside the Earth? -a solid iron core

The Earth's magnetic field is important because it protects us from the solar wind.

The solar wind is a current of charged particles coming at us from the Sun.

When the solar wind nears the Earth, the Earth's magnetic field deflects it away.

This protects the Earth from the radiation, which can be dangerous to life.

It also protects the satellites that we use for communication.

How does the magnectic field protect the Earth? -It deflects the solar wind away from the Earth.

(1) The Earth's magnetic field is important because it protects us from the solar wind.
(2) The solar wind is a current of charged particles coming at us from the Sun.
(3) When the solar wind nears the Earth, the Earth's magnetic field deflects it away.
(4) This protects the Earth from the radiation, which can be dangerous to life.

The Earth's magnetic field is important because it protects us from the solar wind.

The Earth's magnetic field protects the Earth from the solar wind.

Deep inside the Earth is a solid iron core, surrounded by a liquid metal outer core.

When the solar wind nears the earth, the earth’s magnetic field deflects it away.

What protects the Earth from the solar wind? - The Earth's magnetic field

When the solar wind nears the Earth, the Earth's magnetic field deflects it away. This protects the Earth from the radiation, which can be dangerous to life.

The Earth's magnetic field is important because it protects us from the solar wind.

The Earth's magnetic field protects the Earth from the solar wind.

Many scientists believe that the Earth's magnetic field is due to the Earth's rotation.

When the solar wind nears the Earth, the Earth's magnetic field deflects it away.

L5-U3-P4-2 Listening : Magnetic Field Reversal

Magnetic Field Reversal

Scientists now believe that the Earth's magnetic field is about to reverse.

This is called magnetic field reversal.

Every 200,000 to 300,000 years, the Earth's magnetic field reverses.

In other words, the North and South magnetic poles switch places.

This has happened many times in Earth's history, but it has been happening more lately.

What happens during a magnetic field reversal? -The Eath's magnetic poles switch places.

The Earth's magnetic poles switch places.

What happens to magnetic field reversal? -The Earth's magnetic poles switch places.

Scientists now believe that the Earth's magnetic field is about to reverse.

Recent research provides evidence that there have been five magnetic reversals during the past 500,000 years.

The most recent event happened approximately 41,000 years ago.

Recent studies have found that the Earth'smagnetic field has weakened about 5% per decade.

At its current rate, the next reversal could happen within the next century.

How long is a decade?  -10 years

According to the recent research, how long ago does the last reversal occur? -about 41,000 years ago

Many scientists believe that the Earth's magnetic field is due to the Earth's rotation.

Every 200,000 to 300,000 years, the Earth's magnetic field reverses.

The most recent event happened approximately 41,000 years ago.

Scientists now believe that the Earth's magnetic field is about to reverse.

Recent research provides evidence that there have been five magnetic reversals during the past 500,000 years.

Some people worry about the effects of a magnetic field reversal.

They think there is a possibility that it could cause many problems.

For example, without a magnetic field, communications could be disrupted.

Birds and other forms of life could become confused and get lost.

Another effect would be an increase in some forms of cancer, especially skin cancer.

This would be because of an increase in the amount of radiation absorbed by our bodies.

An increase in radiation causes some forms of cancer.

Why could birds become confused if there were no magnetic field ?-They would become confused because they use Earth's magnetic field for

Why are some people worried about magnetic reversal? -They think it could cause many problems.

Some people worry about the effects of a magnetic field reversal.

Why are some people worried about magnetic field reversal? -They think it could cause many problems.

(1) Some people worry about the effects of a magnetic field reversal.
(2) They think there is a possibility that it could cause many problems.
(3) For example, without a magnetic field, communications could be disrupted.
(4) Birds and other forms of life could become confused and get lost.

The possibility that a field reversal would be an extinction event is very low.

There is very little historical evidence to show that previous reversals have caused extinctions.

Humans have been on Earth for millions of years, during which there have been many reversals.

Therefore, scientists believe that any changes would be temporary.

Another theory is that the Earth's outer layer could rotate around the liquid metal outer core that makes up most of the earth.

So in the next reversal continents could shift positions, from north to south.

Imagine, if that happened, Australia would be in the northern hemisphere.

How likely is it that a field reversal would be an extinction event? - It's highly unlikely.

The possibility that a field reversal would be an extinction event is very low. There is very little historical evidence to show that previous reversals have caused extinctions.

If the Earth outer layer rotated around the liquid metal outer core it would cause the continents to shift positions.

With so many theories, how can we know what to believe?

This is important because some events require us to act well in advance.

Otherwise it will be too late to prevent a catastrophe.

This underlines the importance of getting reliable information, backed by strong  evidence.

Some events require us to ...act well in advance to prevent them.

Some people worry about the effects of a magnetic field reversal.

An increase in radiation causes some forms of cancer.

With so many theories, how can we know what to believe?

L5-U3-P4-3 Vocabulary : Decision-Making Verbs

Decision-Making Verbs

Resume: to continue or start again after a pause .

After a short interruption, our work resumed and we worked for another hour.

Work on the project resumed once we passed the safety inspection.

When we lost electricity everything shut down, but a few minutes later the power returned and we resumed our work.

We resume watching the movie as soon as the wireless connection was restored.

The project has been postponed, and we won't resume work until we receive the next payment.

Interrupt: to stop something in progress.

I hate to be interrupted when I'm working, but sometimes it's necessary.

It's difficult to have a conversation with her because she always interrupts.

I'm sorry to interrupt, but I think we need to focus on the main problems.

Be careful not to interrupt the boss when he's speaking.

After a short interruption, our work resumed and we worked for another hour.

I'm trying hard to concentrate, so pelease don't interrupt me.

Reconsider: to reassess or think again about changing something.

I was planning to vote against him, but after hearing him speak, I'm going to reconsider.

I didn't want to hire her at first, but then I reconsidered and offer her the job.

I'm glad I reconsidered your plan because it's turning out to be a big success.

I'm asking you to reconsider your decision, or I'll have no choice but to sue you.

We are planning to sue your company unless you reconsider your decision.

Conclude: to reach a decision; to end something or summarize the main points.

To conclude my presentation, here is a summary of my recommendations.

After hearing arguments for and against the project, we have reached a conclusion.

We have concluded that there are too many risks, so we're going to cancel the project.

Given all the evidence we have come to the conclusion that the pilot was not to blame for the accident.

In conclusion, I think this new pesticide isn't safe for the environment.

Anticipate: to think in advance; to predict what's ahead.

I won the game because it was easy to anticipate my opponent's next move.

He tried to anticipate what we were going to do, but he was completely wrong, so he lost.

I'm anticipating that they won't begin their attack until the weather conditions improve, but they may surprise us.

Given all the evidence we have come to the conclusion that the pilot was not to blame for the accident.

Their sales revenues were much less than they anticipated, so they ran out of money.

Be careful not to interrupt the boss when he's speaking.

I've considered and reconsidered your request, but the answer is still no.

In conclusion, I think this new pesticide isn't safe for the environment.

The project has been postponed, and we won't resume work until we receive the next payment.

We are planning to sue your company unless you reconsider your decision.

Even though he tried to anticipate our attack, we were able to overwhelm his defenses.

To continue or start again after a pause ——to resume.

To reach a decision; to end something or summarize the main points ——to conclude.

To think in advance; to predict what's ahead ——to anticipate.

After a short interruption, our work resumed and we worked for another hour.

I was planning to vote against him, but after hearing him speak, I'm going to reconsider.

After hearing arguments for and against the project, we have reached a conclusion.

I hate to be interrupted when I'm working, but sometimes it's necessary.

Are you sure you won't reconsider your decision?

We have concluded that there are too many risks, so we're going to cancel the project.

We resumed watching the movie as soon as the wireless connection was restored.

I'm asking you to reconsider your decision, or I'll have no choice but to sue you.

L5-U3-P4-4 Vocabulary : Status of Affairs

Status of Affairs

Permanent: to be fixed or unchanging, the opposite of temporary.

He plans to stay there permanently.

He has decided to become a permanent resident of China.

Once they established permanent boundaries, they have to fight to defend their territory from invaders.

The development of agriculture allowed humans to settle down and build permanent communities.

Humans lived as nomads until they decided to settle down and build permanent communities.

Temporary: only lasting for a short time, the opposite of permanent.

We can only offer him a temporary position in the company.

This isn't the kind of job he wants, but it's okay as something temporary, until he can find something better.

Until we move into the new building we'll use this office as our temporary base.

That company places people in part-time, temporary positions.

If you do well as a temporary worker, you may be hired for a permanent position.

Definite: well defined, precise, certain, unchanging.

We can't begin the project until you give us a more definite schedule.

We can't give you a definite answer until we get more information.

Until we have more definite information about your plans, we can't make any promises.

They couldn’t solve the problem until they could clearly define it.

We don't know their exact location, but they are definitely in this general area.

Obvious: easy to see, stands out.

Of the job candidates we interviewed, he was the obvious choice.

It's obvious that he can't afford to buy that house.

It was an obvious lie, but some people still believed it.

From her facial expression, it was obvious that she really disliked him.

Trivial: of little or no importance, insignificant.

It's a trivial detail, so there's no need to worry about it.

Those problems are not trivial, so we need to find a solution.

She spends her time worrying about trivial details, so she wastes a lot of time.

Only lasting for a short time ——temporary.

Easy to see, stands out ——obvious.

Of little or no importance, insignificant ——trivial.

It's obvious that he can't afford to buy that house.

We can't give you a definite answer until we get more information.

He has decided to become a permanent resident of China.

We can only offer him a temporary position in the company.

We need you to be more definite about your plans for the next six months.

From her facial expression, it was obvious that she really disliked him.

She spends her time worrying about trivial details, so she wastes a lot of time.

Humans lived as nomads until they decided to settle down and build permanent communities.

He thinks it's a trivial matter, but I think it's going to cause big problems if we ignore it.

It's a trivial detail, so there's no need to worry about it.

Those problems are not trivial, so we need to find a solution.

We can only offer him a temporary position in the company.

He plans to stay there permanently.

We can't begin the project until you give us a more definite schedule.

Of the job candidates we interviewed, he was the obvious choice.

Those problems are not trivial, so we need to find a solution.

If you do well as a temporary worker, you may be hired for a permanent position.

He thinks it’s a trivial matter, but I think it’s going to cause big problems if we ignore it.

After hearing arguments for and against the project, we have reached a conclusion

We have concluded that there are too many risks, so we’re going cancel the project.

I’ve considered and reconsidered your request, but the answer is still no.

We can’t make a reservation for your flight until you give us a definite return date.

Humans lived as nomads until they decided to settle down and permanent communities.

We resumed watching the movie as soon as the wireless connection was restored.

The conclusion is often the most important part of a presentation.

I’ve considered and reconsidered your request, but the answer is still no.

After hearing arguments for and against the project, we have reached a conclusion.

In conclusion, I think this new pesticide isn’t safe for the environment.

We can’t make a reservation for your flight until you give us a definite return date.

We need you to be more definite about your plans for the next 6 months.

L5-U3-P4-5 Dialogue : Argument over Investment

W: I just heard what you did. You did it without consulting me.

M: Yes, I talked to them and decided to invest more money. I didn't have time to consult with you, and I trust them.

W: That's our money not yours. We've been saving it to buy a house. You had no right to make that decision without letting me know. How can I trust you?

What had they've been saving for? -to buy a house

You did it without consulting me.

Yes, I talk to them I decided to invest more money.

You had no right to make that decision without letting me know.

That's our money, not yours.

I didn't have time to consult with you, and I trust them.

M: Look, it was an opportunity I couldn't resist. I'm sure it's going to be okay.

W: No it isn't. It's a stupid investment and it's going to fail. I really hate you now.

M: That's a really strong word for simply disagreeing. Why can't we disagree without becoming so emotional?

W: We aren't just disagreeing. You've broken your promise again. I can't trust you anymore, especially when you keep doing stupid things that affect me.

She says she hates him because ...he has broken his promise, so she can't trust him.

Why can't we disagree without becoming so emotional.

She doesn't trust him anymore?

I can't trust you anymore, especially when you keep doing stupid things that affect me.

(1) Look, it was an opportunity I couldn't resist. I'm sure it's going to be okay.
(2) No it isn't. It's a stupid investment and it's going to fail.
(3) I really hate you now.
(4) That's a really strong word for simply disagreeing.

We aren't just disagreeing.

She's upset because he has broken his promise again.

It's a stupid investment and it's going to fail. I really hate you now.

Why is she so upset? -He has broken his promise.

M: You say I'm being stupid, but it's just that we don't agree.

W: No, that's not the point. You are not listening. You said you wouldn't do anything unless we both agreed. And look what you've done. Your promises are just empty words. I really despise you now.

What is the point? - He is broken his promise

You're not listening.

He is broken his promise

You said you wouldn't do anything unless we both agreed.

You said you wouldn't do anything unless we both agreed.

Your promises are just empty words.

And look what you've done.

Her point is that he didn't keep his promise.

What isn't the point? -they disagree

M: Well, what should we do? If you keep talking like that, we had better break up.

W: Yes, we should. I've had enough. I don't want to see you anymore, and I don't want you to even contact me.

M: Sure, if that's what you really want. But I want you to know that I haven't been lying to you.

W: Don't say anything more. I don't want to hear it. You are a fool and you can't even see what you are doing.

I don't want to see you anymore, and I don't want you to even contact me.

Don't say anything more.

If you keep talking like that, we had better break up.

But I want you to know that I haven't been lying to you.

I don't want to hear it.

But I want you to know that I haven't been lying to you.

M: Hi, I'm calling to apologize. Did you get my flowers?

W: Yes, but I told you not to call me.

M: Yes, I know, but I don't want our relationship to end like this. We've been through too much together. Let's give it another try.

W: I'm sorry. I think it's too late. This was the last straw.

What did he send to her? - He sent her some flowers.

She thinks it's to late to save their relationship because ...she can't take any more of his broken promises.

Why did he call? - to apologize

M: Please give me another chance. You were right about everything. I'll try to get the money back.

W: When you get the money back, you can call me again. If you don't, you can pay me what you owe me, and then leave me alone.

M: OK, I'll get it back. I'll do anything to get you back in my life.

W: I'll think about it.

When you get the money back, you can call me again. If you don't, you can pay me what you owe me, and then leave me alone.

He needs to get the money back before he can call her again.

That's give it another try.

I'll do anything to get you back in my life.

He wants to apologize and hopefully save their relationship.

She's angry because he made an investment without consulting her.

When you get the money back you can call me again. If you don't, you can pay me what you owe me, and then leave me alone.

You said you wouldn't do anything unless we both agreed.

Hi, I'm calling to apologize.

When you get the money back, you can call me again.

You had no right to make that decision without letting me know.

She thinks it's to late to save their relationship because she can't take any more of his broken promises.

What does he need to do before he can call her again ? -He needs to get the money back.

She thinks it's too late to save their relationship because she can't take any more of his broken promises.