Shadowing Practice: The Most Misunderstood Concept in Physics - Learn English Speaking with Video
בחר מצב תרגול
כל מצב פותח חדר תרגול במסך מלא.
270 משפטים
אם המשפטים קצרים או ארוכים מדי, לחץ על ערוך כדי להתאים אותם.
1
- This is a video about one of the most important, yet least understood concepts in all of physics.
2
It governs everything from molecular collisions to humongous storms.
3
From the beginning of the universe through its entire evolution, to its inevitable end.
4
It may, in fact, determine the direction of time and even be the reason that life exists.
5
To see the confusion around this topic, you need to ask only one simple question.
6
What does the Earth get from the sun?
7
- What does the earth get from sun?
8
- Well, it's light rays?
9
- What do we get from the sun? - Heat.
10
- Warmth. - Warmth, light.
11
- Vitamin D, we get vitamin D from- - We do get vitamin D from the ultraviolet rays.
12
- Well, a lot of energy.
13
- What does the earth get from this, energy?
14
- Yeah, energy.
15
- Energy. - Nailed it.
16
Every day, the earth gets a certain amount of energy from the sun.
17
And then how much energy does the earth radiate back into space relative to that amount that it gets from the sun?
18
- Probably not as much, I, you know, I don't believe it's just radiating right back.
19
- I'd say less.
20
- Less. - Less. - I say less.
21
- I guess about 70%?
22
- It is a fraction.
23
- I'd say 20%.
24
- Because... - Because we use some of it.
25
- We use some of the energy. - Mm-hmm.
26
- We consume a lot, right?
27
- But the thing about energy is it never really goes away.
28
You can't really use it up.
29
- It would have to break even, wouldn't it?
30
Same amount, yeah.
31
- You know, cause and effect.
32
It'd be equal in some ways, right?
33
- For most of the earth's history, it should be exactly the same amount of energy in from the sun as earth radiates into space.
34
- Wow. - Because if we didn't do that, then the earth would get a lot hotter, that'd be a problem.
35
- That'd be a big problem.
36
- So, if that is the case...
37
- Yeah. - Then what are we really getting from the sun?
38
- That's a good question.
39
- Hmm. - It gives us a nice tan.
40
- It gives us a nice tan, I love it.
41
We're getting something special from the sun.
42
- I don't know, what do we get without the energy?
43
- But nobody talks about it.
44
To answer that, we have to go back to a discovery made two centuries ago.
45
In the winter of 1813, France was being invaded by the armies of Austria, Prussia, and Russia.
46
The son of one of Napoleon's generals was Sadi Carnot, a 17-year-old student.
47
On December 29th, he writes a letter to Napoleon to request to join in the fight.
48
Napoleon preoccupied in battle, never replies.
49
but Carnot gets his wish a few months later when Paris is attacked.
50
The students defend a chateau just east of the city, but there're no match for the advancing armies, and Paris falls after only a day of fighting.
51
Forced to retreat, Carnot is devastated.
52
Seven years later, he goes to visit his father who's fled to Prussia after Napoleon's downfall.
53
His father was not only a general, but also a physicist.
54
He wrote an essay on how energy is most efficiently transferred in mechanical systems.
55
When his son comes to visit, they talk at length about the big breakthrough of the time, steam engines.
56
Steam engines were already being used to power ships, mine ore, and excavate ports.
57
And it was clear that the future industrial and military might of nations depended on having the best steam engines.
58
But French designs were falling behind those of other countries like Britain.
59
So, Sadi Carnot took it upon himself to figure out why.
60
At the time, even the best steam engines only converted around 3% of thermal energy into useful mechanical work.
61
If he could improve on that, he could give France a huge advantage and restore its place in the world.
62
So he spends the next three years studying heat engines, and one of his key insights involves how an ideal heat engine would work, one with no friction and no losses to the environment.
63
It looks something like this.
64
Take two really big metal bars, one hot and one cold.
65
The engine consists of a chamber filled with air, where heat can only flow in or out through the bottom.
66
Inside the chamber is a piston, which is connected to a flywheel.
67
The air starts at a temperature just below that of the hot bar.
68
So first, the hot bar is brought into contact with the chamber.
69
The air inside expands with heat flowing into it to maintain its temperature.
70
This pushes the piston up, turning the flywheel.
71
Next, the hot bar is removed, but the air in the chamber continues to expand, except now without heat entering, the temperature decreases.
72
In the ideal case, until it is the temperature of the cold bar.
73
The cold bar is brought into contact with the chamber and the flywheel pushes the piston down.
74
And as the air is compressed, heat is transferred into the cold bar.
75
The cold bar is removed.
76
The flywheel compresses the gas further increasing its temperature until it is just below that of the hot bar.
77
Then the hot bar is connected again and the cycle repeats.
78
Through this process, heat from the hot bar is converted into the energy of the flywheel.
79
And what's interesting to note about Carnot's ideal engine is that it is completely reversible.
80
If you ran the engine in reverse, first the air expands lowering the temperature, then the chamber is brought into contact with the cold bar, the air expands more, drawing in heat from the cold bar.
81
Next, the air is compressed, increasing its temperature.
82
The chamber is placed on top of the hot bar and the energy of the flywheel is used to return the heat back into the hot bar.
83
However many cycles were run in the forward direction, you could run the same number in reverse, and at the end, everything would return to its original state with no additional input of energy required.
84
So by running an ideal engine, nothing really changes.
85
You can always undo what you did.
86
So what is the efficiency of this engine?
87
Since it's fully reversible, you might expect the efficiency to be 100%, but that is not the case.
88
Each cycle, the energy of the flywheel increases by the amount of heat flowing into the chamber from the hot bar, minus the heat flowing out of the chamber at the cold bar.
89
So to calculate the efficiency, we divide this energy by the heat input from the hot bar.
90
Now the heat in on the hot side is equal to the work done by the gas on the piston, and this will always be greater than the work done by the piston on the gas on the cold side, which equals the heat out.
91
And this is because on the hot side, the hot gas exerts a greater pressure on the piston than that same gas when cold.
92
To increase the efficiency of the engine, you could increase the temperature of the hot side, or decrease the temperature of the cold side, or both.
93
Lord Kelvin learns of Carnot's ideal heat engine and realizes it could form the basis for an absolute temperature scale.
94
Imagine that the gas is allowed to expand an extreme amount, so much that it cools to the point where all the gas particles effectively stop moving.
95
Then they would exert no pressure on the piston, and it would take no work to compress it on the cold side, so no heat would be lost.
96
This is the idea of absolute zero, and it would make for a 100% efficient engine.
97
Using this absolute temperature scale, the Kelvin scale, we can replace the amount of heat in and out with the temperature of the hot and cold side respectively, because they are directly proportional.
98
So we can express efficiency like this, which we can rewrite like this.
99
What we have learned is that the efficiency of an ideal heat engine doesn't depend on the materials or the design of the engine, but fundamentally on the temperatures of the hot and cold sides.
100
To reach 100% efficiency, you'd need infinite temperature on the hot side or absolute zero on the cold side, both of which are impossible in practice.
101
So even with no friction or losses to the environment, it's impossible to make a heat engine 100% efficient.
102
And that's because to return the piston to its original position, you need to dump heat into the cold bar.
103
So not all the energy stays in the flywheel.
104
Now, in Carnot's time, high pressure steam engines could only reach temperatures up to 160 degrees Celsius.
105
So their theoretical maximum efficiency was 32%, but their real efficiency was more like 3%.
106
That's because real engines experience friction, dissipate heat to the environment, and they don't transfer heat at constant temperatures.
107
So for just as much heat going in, less energy ends up in the flywheel.
108
The rest is spread out over the walls of the cylinder, the axle of the flywheel, and is radiated out into the environment.
109
When energy spreads out like this, it is impossible to get it back.
110
So this process is irreversible.
111
The total amount of energy didn't change, but it became less usable.
112
Energy is most usable when it is concentrated and less usable when it's spread out.
113
Decades later, German physicist, Rudolf Clausius, studies Carnot's engine, and he comes up with a way to measure how spread out the energy is.
114
He calls this quantity, entropy.
115
When all the energy is concentrated in the hot bar, that is low entropy, but as the energy spreads to the surroundings, the walls of the chamber and the axle will entropy increases.
116
This means the same amount of energy is present, but in this more dispersed form, it is less available to do work.
117
In 1865, Clausius summarizes the first two laws of thermodynamics like this.
118
First, the energy of the universe is constant.
119
And second, the entropy of the universe tends to a maximum.
120
In other words, energy spreads out over time.
121
The second law is core to so many phenomena in the world.
122
It's why hot things cool down and cool things heat up, why gas expands to fill a container, why you can't have a perpetual motion machine, because the amount of usable energy in a closed system is always decreasing.
123
The most common way to describe entropy is as disorder, which makes sense because it is associated with things becoming more mixed, random, and less ordered.
124
But I think the best way to think about entropy is as the tendency of energy to spread out.
125
So why does energy spread out over time?
126
I mean, most of the laws of physics work exactly the same way forwards or backwards in time.
127
So how does this clear time dependence arise?
128
Well, let's consider two small metal bars, one hot and one cold.
129
For this simple model, we'll consider only eight atoms per bar.
130
Each atom vibrates according to the number of energy packets it has.
131
The more packets, the more it vibrates.
132
So let's start with seven packets of energy in the left bar and three in the right.
133
The number of energy packets in each bar is what we'll call a state.
134
First, let's consider just the left bar.
135
It has seven energy packets, which are free to move around the lattice.
136
This happens nonstop.
137
The energy packets hop randomly from atom to atom giving different configurations of energy, but the total energy stays the same the whole time.
138
Now, let's bring the cold bar back in with only three packets and touch them together.
139
The energy packets can now hop around between both bars creating different configurations.
140
Each unique configuration is equally likely.
141
So what happens if we take a snapshot at one instant in time and see where all the energy packets are?
142
So stop, look at this.
143
Now there are nine energy packets in the left bar, and only one in the right bar.
144
So heat has flowed from cold to hot.
145
Shouldn't that be impossible because it decreases entropy?
146
Well, this is where Ludwig Boltzmann made an important insight.
147
Heat flowing from cold to hot is not impossible, it's just improbable.
148
There are 91,520 configurations with nine energy packets in the left bar, but 627,264 with five energy packets in each bar.
149
That is the energy is more than six times as likely to be evenly spread between the bars.
150
But if you add up all the possibilities, you find there's still a 10.5% chance that the left bar ends up with more energy packets than it started.
151
So, why don't we observe this happening around us?
152
Well, watch what happens as we increase the number of atoms to 80 per bar and the energy packets to 100, with 70 in the left bar and 30 in the right.
153
There is now only a 0.05% chance that the left solid ends up hotter than it started.
154
And this trend continues as we keep scaling up the system.
155
In everyday solids, there are around 100 trillion, trillion atoms and even more energy packets.
156
So heat flowing from cold to hot is just so unlikely that it never happens.
157
Think of it like this Rubik's cube.
158
Right now, it is completely solved, but I'm gonna close my eyes and make some turns at random.
159
If I keep doing this, it will get further and further from being solved.
160
But how can I be confident that I'm really messing this cube up?
161
Well, because there's only one way for it to be solved, a few ways for it to be almost solved, and quintillions of ways for it to be almost entirely random.
162
Without thought and effort, every turn moves the Rubik's cube from a highly unlikely state that of it being solved to a more likely state, a total mess.
163
So if the natural tendency of energy is to spread out and for things to get messier, then how is it possible to have something like air conditioning where the cold interior of a house gets cooler and the hot exterior gets hotter?
164
Energy is going from cold to hot, decreasing the entropy of the house.
165
Well, this decrease in entropy is only possible by increasing the entropy a greater amount somewhere else.
166
In this case, at a power plant, the concentrated chemical energy and coal is being released, heating up the power plant in its environment, spreading to the turbine the electric generators, heating the wires all the way to the house, and producing waste heat in the fans and compressor.
167
Whatever decrease in entropy is achieved at the house is more than paid for by an increase in entropy required to make that happen.
168
But if total entropy is constantly increasing and anything we do only accelerates that increase, then how is there any structure left on earth?
169
How are there hot parts separate from cold parts?
170
How does life exist?
171
Well, if the earth were a closed system, the energy would spread out completely, meaning, all life would cease, everything would decay and mix, and eventually, reach the same temperature.
172
But luckily, earth is not a closed system, because we have the sun.
173
What the sun really gives us is a steady stream of low entropy that is concentrated bundled up energy.
174
The energy that we get from the sun is more useful than the energy we give back.
175
It's more compact, it's more clumped together.
176
Plants capture this energy and use it to grow and create sugars.
177
Then animals eat plants and use that energy to maintain their bodies and move around.
178
Bigger animals get their energy by eating smaller animals and so on.
179
And each step of the way, the energy becomes more spread out.
180
- Okay, interesting.
181
- Yeah. - Oh wow, I did not know that.
182
- There you go.
183
Ultimately, all the energy that reaches earth from the sun is converted into thermal energy, and then it's radiated back into space.
184
But in fact, it's the same amount.
185
I know this is a- - You do know this is...
186
- I'm a PhD physicist.
187
- Oh, okay, but anyway, so... - I trust you.
188
The increase in entropy can be seen in the relative number of photons arriving at and leaving the earth.
189
For each photon received from the sun, 20 photons are emitted, and everything that happens on earth, plants growing, trees falling, herds stampeding, hurricanes and tornadoes, people eating, sleeping, and breathing.
190
All of it happens in the process of converting fewer, higher energy photons into 20 times as many lower energy photons.
191
Without a source of concentrated energy and a way to discard the spread out energy, life on earth would not be possible.
192
It has even been suggested that life itself may be a consequence of the second law of thermodynamics.
193
If the universe tends toward maximum entropy, then life offers a way to accelerate that natural tendency, because life is spectacularly good at converting low entropy into high entropy.
194
For example, the surface layer of seawater produces between 30 to 680% more entropy when cyanobacteria and other organic matter is present than when it's not.
195
Jeremy England takes this one step further.
196
He's proposed that if there is a constant stream of clumped up energy, this could favor structures that dissipate that energy.
197
And over time, this results in better and better energy dissipators, eventually resulting in life.
198
Or in his own words, "You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant." So life on earth survives on the low entropy from the sun, but then where did the sun get its low entropy?
199
The answer is the universe.
200
If we know that the total entropy of the universe is increasing with time, then it was lower entropy yesterday and even lower entropy the day before that, and so on, all the way back to the Big Bang.
201
So right after the Big Bang, that is when the entropy was lowest.
202
This is known as the past hypothesis.
203
It doesn't explain why the entropy was low, just that it must have been that way for the universe to unfold as it has.
204
But the early universe was hot, dense, and almost completely uniform.
205
I mean, everything was mixed and the temperature was basically the same everywhere, varying by at most 0.001%.
206
So how is this low entropy?
207
Well, the thing we've left out is gravity.
208
Gravity tends to clump matter together.
209
So taking gravity into account, having matter all spread out like this, would be an extremely unlikely state, and that is why it's low entropy.
210
Over time, as the universe expanded and cooled, matter started to clump together in more dense regions.
211
And in doing so, enormous amounts of potential energy were turned into kinetic energy.
212
And this energy could also be used like how water flowing downhill can power a turbine.
213
But as bits of matter started hitting each other, some of their kinetic energy was converted into heat.
214
So the amount of useful energy decreased.
215
Thereby, increasing entropy.
216
Over time, the useful energy was used.
217
In doing so, stars, planets, galaxies, and life were formed, increasing entropy all along.
218
The universe started with around 10 to the 88 Boltzmann constants worth of entropy.
219
Nowadays, all the stars in the observable universe have about 9.5 times 10 to the 80.
220
The interstellar and intergalactic medium combined have almost 10 times more, but still only a fraction of the early universe.
221
A lot more is contained in neutrinos and in photons of the cosmic microwave background.
222
In 1972, Jacob Bekenstein proposed another source of entropy, black holes.
223
He suggested that the entropy of a black hole should be proportional to its surface area.
224
So as a black hole grows, its entropy increases.
225
Famous physicists thought the idea was nonsense and for good reason.
226
According to classical thermodynamics, if black holes have entropy, then they should also have a temperature.
227
But if they have temperatures, they should emit radiation and not be black after all.
228
The person who set out to prove Bekenstein wrong was Stephen Hawking.
229
But to his surprise, his results showed that black holes do emit radiation, now known as Hawking radiation, and they do have a temperature.
230
The black hole at the center of the Milky Way has a temperature of about a hundred trillionth of a Kelvin, emitting radiation that is far too weak to detect.
231
So still pretty black.
232
But Hawking confirmed that black holes have entropy and Bekenstein was right.
233
Hawking was able to refine Bekenstein's proposal and determine just how much entropy they have.
234
The super massive black hole at the center of the Milky Way has about 10 to the 91 Boltzmann constants of entropy.
235
That is 1,000 times as much as the early observable universe, and 10 times more than all the other particles combined.
236
And that is just one black hole.
237
All black holes together account for 3 times 10 to the 104 Boltzmann constants worth of entropy.
238
So almost all the entropy of the universe is tied up in black holes.
239
That means, the early universe only had about 0.000000000000003% of the entropy it has now.
240
So the entropy was low, and everything that happens in the universe like planetary systems forming, galaxies merging, asteroids crashing, stars dying, to life itself flourishing, all of that can happen because the entropy of the universe was low and it has been increasing, and it all happens only in one direction.
241
We never see an asteroid uncrash or a planetary system unmix into the cloud of dust and gas that made it up.
242
There is a clear difference between going to the past and the future, and that difference comes from entropy.
243
The fact that we are going from unlikely to more likely states is why there is an arrow of time.
244
This is expected to continue until eventually, the energy gets spread out so completely that nothing interesting will ever happen again.
245
This is the heat death of the universe.
246
In the distant future, more than 10 to the 100 years from now, after the last black hole has evaporated, the universe will be in its most probable state.
247
Now, even on large scales, you would not be able to tell the difference between time moving forwards or backwards, and the arrow of time itself would disappear.
248
So it sounds like entropy is this awful thing that leads us inevitably towards the dullest outcome imaginable.
249
But just because maximum entropy has low complexity does not mean that low entropy has maximum complexity.
250
It's actually more like this tea and milk.
251
I mean, holding it like this is not very interesting.
252
But as I pour the milk in, the two start to mix and these beautiful patterns emerge.
253
They arise in an instant and before you know it, they're gone back to being featureless.
254
Both low and high entropy are low in complexity.
255
It's in the middle where complex structures appear and thrive.
256
And since that's where we find ourselves, let's make use of the low entropy we've got while we can.
257
With the right tools, we can understand just about anything, from a cup of tea cooling down to the evolution of the entire universe.
258
And if you're looking for a free and easy way to add powerful tools to your arsenal, then you should check out this video sponsor, brilliant.org.
259
With Brilliant, you can master key concepts in everything from math and data science to programming and physics.
260
All you need to do is set your goal, and Brilliant will design the perfect learning path for you, equipping you with all the tools you need to reach it.
261
Want to learn how to think like a programmer?
262
Then Brilliant's latest course, "Thinking in Code" is a fast and easy way to get there.
263
Using an intuitive drag and drop editor, it teaches you what you really need to know, including essential concepts like nesting and conditionals.
264
You can start by jumping right in to program a robot and then learn how to apply your new tools to your everyday life, like automating reminders on your phone or building a bot that filters your matches on a dating app.
265
What I love about Brilliant is that they connect what you learn to real world examples.
266
And because each lesson is hands-on, you'll build real intuition, so you can put what you've learned to good use.
267
To try everything Brilliant has to offer free for a full 30 days, visit brilliant.org/veritasium.
268
I will put that link down in the description.
269
And through that link, the first 200 of you to sign up will get 20% off Brilliant's annual premium subscription.
270
So I wanna thank Brilliant for sponsoring this video, and I wanna thank you for watching.
הורד אפליקציה
כל מה שאתה צריך כדי לדבר בשטף
הגיית AIציון לכל משפט
תרגול IPAשלוט בכל צליל
אוצר מיליםבנה את מאגר המילים שלך
משחק אוצר מיליםלמד תוך כדי משחק
אותו ערוץ
C11
White holes and wormholes are probably real. Here's why.
Daily ConversationUniversity Students
C11
Something is jamming GPS over Europe. Here's what we found
Daily ConversationUniversity StudentsWorking Adults
C11
Why is there antimatter?
Daily ConversationUniversity Students
C11
No device could prove Einstein wrong... until now
Daily ConversationUniversity Students
C11
Why It Was Almost Impossible to Make the Blue LED
Daily ConversationUniversity StudentsWorking Adults
C12
You've (Likely) Been Playing The Game Of Life Wrong
Daily ConversationUniversity StudentsWorking Adults
B22
We're trying something new...
Daily ConversationWorking Adults
C120
How does light 'know' the shortest path?
IELTS PrepTOEFL PrepUniversity Students
C13
Why Cold Drinks Were Deadly Before 1914
Business EnglishUniversity StudentsWorking Adults
C14
Exposing The Flaw In Our Phone System
Business EnglishUniversity StudentsWorking Adults
C12
Our Greatest Delusion
IELTS PrepTOEFL PrepUniversity Students
C13
The Most Controversial Problem in Philosophy
IELTS PrepTOEFL PrepUniversity Students
C13
We've Been Using The Wrong Science In Court For 50 years
IELTS PrepTOEFL PrepUniversity Students
B24
Explaining Pi With Pizza
University Students
B214
5 Fun Physics Phenomena
Daily ConversationUniversity Students
C12
The Absurd Engineering Behind the Internet
Daily ConversationUniversity StudentsWorking Adults
B11
Falling ladders - why does this happen?
IELTS PrepTOEFL PrepHigh School Students
C110
How a slinky falls in slow motion #shorts
University StudentsWorking Adults
C13
We're 99.9% sure this pattern is true, but no one can prove it
IELTS PrepTOEFL PrepUniversity Students
B23
What is the secret of a good life? Lessons from the longest study on happiness
Business EnglishDaily ConversationUniversity Students
FOR YOU
המלץ על סרטון
C12
249 משפטים
The Speed of Light Isn't a Limit. It's a Converter
IELTS PrepTOEFL PrepUniversity Students
C14
34 משפטים
The Evolution of Human Skin Colour | BBC Earth Science
IELTS PrepTOEFL PrepUniversity Students
C16
113 משפטים
What If Earth got Kicked Out of the Solar System? Rogue Earth
IELTS PrepTOEFL PrepUniversity Students
C13
627 משפטים
Brian Cox - The Most Mysterious Facts About The Universe
IELTS PrepTOEFL PrepUniversity Students
C12
76 משפטים
The Nucleus: Crash Course Chemistry #1
IELTS PrepTOEFL PrepUniversity Students
C16
32 משפטים
Anti-matter & nuclear weapons: Why technology is always a double-edge sword | Don Lincoln
IELTS PrepTOEFL PrepUniversity Students
C15
92 משפטים
The Dumbest Animal Alive
IELTS PrepTOEFL PrepUniversity Students
C168
44 משפטים
Why is it Hot Underground?
IELTS PrepTOEFL PrepUniversity Students
C18
144 משפטים
What Did Ancient Humans Do at Night?
IELTS PrepTOEFL PrepUniversity Students
C12
155 משפטים
Let There Be Light: Maxwell's Equation EXPLAINED for BEGINNERS
IELTS PrepTOEFL PrepUniversity Students
C114
316 משפטים
The Most Controversial Idea In Physics
IELTS PrepTOEFL PrepUniversity Students
אוצר מילים והערות הגייה לשיעור הזה
שיעור הדיבור הזה ברמה C1 מבוסס על הסרטון “The Most Misunderstood Concept in Physics”. המילים שחוזרות הכי הרבה: energy, entropy, bar, heat, hot. בסרטון הזה יש 270 משפטים ו-4149 מילים לתרגול Shadowing. הדיבור נמשך 27:14. הדובר מדבר בקצב טבעי של כ-152 מילים בדקה, קרוב לשיחה יומיומית. 83% מהמילים נמצאות בין 3,000 המילים הנפוצות ביותר באנגלית; כדאי ללמוד את השאר לפני שמתחילים.
אוצר מילים מרכזי בסרטון הזה
15 המילים המתקדמות ביותר בסרטון, עם ההגייה והמשמעות שלהן:
| מילה | הגייה | משמעות |
|---|---|---|
| packet שם עצם | /ˈpæk.ɪt/ | חֲבִילָה |
| piston שם עצם | /ˈpɪstən/ | בוכנה \ בֻּכְנָה |
| atom שם עצם | /ˈætəm/ | אָטוֹם |
| photon שם עצם | /ˈfəʊtɒn/ | פוטון |
| physicist שם עצם | /ˈfɪzɪsɪst/ | פִיזִיקַאי |
| thermodynamics שם עצם | /ˌθɜː(ɹ)moʊdaɪˈnæmɪks/ | תֶּרְמוֹדִינָמִיקָה |
| cube שם עצם | /kjub/ | קובייה, קֻבִּיָּה |
| tendency שם עצם | /ˈtɛn.dən.si/ | נטייה \ נְטִיָּה |
| vitamin שם עצם | /ˈvɪt.ə.mɪn/ | וִיטָמִין |
| complexity שם עצם | /kəmˈplɛk.sɪ.ti/ | מורכבות |
| axle שם עצם | /ˈæksəl/ | סֶרֶן |
| radiate פועל | /ˈɹeɪdieɪt/ | קָרַן |
| planetary שם תואר | /ˈplænɪˌtɛəri/ | פלנטרי |
| turbine שם עצם | /ˈtɜː.baɪn/ | טוּרְבִּינָה |
| particle שם עצם | /ˈpɑɹtək(ə)l/ | חֶלְקִיק, גַרגִיר |
Phrasal verbs שתשמעו
| מילה | משמעות |
|---|---|
| check out פועל | בדק |
| figure out פועל | הֵבִין, מצא תשובה |
משפטים שכדאי לחזור עליהם
משפטים קצרים ושלמים מהסרטון שאפשר להשתמש בהם בשיחה יומיומית:
- You can't really use it up.
- We're getting something special from the sun.
- First, let's consider just the left bar.
- Shouldn't that be impossible because it decreases entropy?
- So, why don't we observe this happening around us?
דקדוק בסרטון הזה
המבנים שהדובר משתמש בהם הכי הרבה, עם המילים המדויקות מהסרטון:
| מבנה | בסרטון |
|---|---|
| משפטי תנאי (Conditional sentences) if + clause, will/would + verb — תנאי ותוצאה שלו | If I keep doing this, it will get |
| סביל (Passive voice) be + past participle — הדגש הוא על מה שקורה, לא על מי שעושה את הפעולה | being invaded · is attacked · is connected |
| הווה מושלם (Present perfect) have/has + past participle — פעולה שקרתה בעבר ועדיין יש לה חשיבות או השפעה עכשיו | have learned · has flowed · has even been suggested |
| משפטי זיקה (Relative clauses) who / which + clause — מידע נוסף על אדם או דבר | piston, which is · disorder, which makes · packets, which are |
הגייה ששווה לשים לב אליה
הדובר משתמש ב-34 קיצורים וצורות מקוצרות, כמו don't, I'm, can't. אמרו אותם בצורה הקצרה, כפי שאתם שומעים אותם.
- הצלילים של “th”: thermodynamics /ˌθɜː(ɹ)moʊdaɪˈnæmɪks/, thermal /ˈθɜːməl/, breakthrough /ˈbɹeɪk.θɹuː/, hypothesis /haɪˈpɒθɪsɪs/, theoretical /ˌθi.əˈɹɛt.ɪ.kəl/
- הצלילים של “sh” ו-“zh”: configuration /kənˌfɪɡ.əˈɹeɪ̯.ʃən/, friction /ˈfɹɪkʃən/, fraction /ˈfɹæk.ʃən/, subscription /səbˈskɹɪpʃən/
- מילים ארוכות — שימו לב להטעמה: configuration /kənˌfɪɡ.əˈɹeɪ̯.ʃən/, thermodynamics /ˌθɜː(ɹ)moʊdaɪˈnæmɪks/, complexity /kəmˈplɛk.sɪ.ti/, observable /əbˈzɜː.və.bəl/, reversible /ɹəˈvɜː(ɹ)sɪbəl/
צלילים שדוברי עברית מתקשים בהם:
- /w/ — שפתיים מעוגלות, לא /v/: backward /ˈbækwɚd/, quantity /ˈkwɑn(t)ɪti/, consequence /ˈkɑn.sɪ.kwəns/
- /æ/ — פתוח יותר מה-“אֶ” העברית, לא כמו “a” ב-“cup”: packet /ˈpæk.ɪt/, atom /ˈætəm/, thermodynamics /ˌθɜː(ɹ)moʊdaɪˈnæmɪks/, axle /ˈæksəl/, planetary /ˈplænɪˌtɛəri/
- /r/ — הלשון לא נוגעת בשום מקום, לא ה-“ר” הגרונית: entropy /ˈɛntɹəpi/, concentrate /ˈkɑn.sən.tɹeɪt/, configuration /kənˌfɪɡ.əˈɹeɪ̯.ʃən/, thermodynamics /ˌθɜː(ɹ)moʊdaɪˈnæmɪks/, friction /ˈfɹɪkʃən/
איך לתרגל עם הסרטון הזה
- הקשיבו לכל הסרטון פעם אחת בלי לדבר, ורשמו את המילים שאתם לא מכירים.
- התחילו במהירות 0.75×, תרגלו Shadowing משפט אחר משפט, וחזרו למהירות רגילה כשזה מרגיש קל.
- הקליטו את עצמכם והשוו למקור, תוך תשומת לב למילים כמו packet, piston, atom.
מהי טכניקת השאדואינג?
שאדואינג היא טכניקת למידת שפה מבוססת מדע שפותחה במקור להכשרת מתורגמנים מקצועיים ופופולרית על ידי הפוליגלוט ד"ר אלכסנדר ארגואלס. השיטה פשוטה אך עוצמתית: אתה מקשיב לאודיו באנגלית ילידית וחוזר עליו בקול רם מיד — כמו צל העוקב אחרי הדובר עם עיכוב של 1–2 שניות בלבד. בניגוד להאזנה פסיבית או תרגילי דקדוק, שאדואינג מכריח את המוח והשרירים בפה לעבד ולשחזר דפוסי דיבור אמיתיים בו זמנית. מחקרים מראים שזה משפר משמעותית את דיוק ההגייה, האינטונציה, הקצב, הדיבור המחובר, הבנת השמיעה ושטף הדיבור — מה שהופך אותו לאחת השיטות היעילות ביותר להכנה לIELTS Speaking ולתקשורת באנגלית בעולם האמיתי.