TOEFL: A short history on the development and the importance of the periodic table.
You can download the file [ HERE ].
It is important to read the vocabulary before you watch the video. This will improve your ability to understand the video. It will also help you understand how the new vocabulary is used naturally.
The first time you watch the video, just try to understand the overall situation.
First try to answer all the questions from memory. Then rewatch the video and try to answer the questions that you missed.
Watch the video again while you read the script. Reading and listening at the same time will help you hear each individual word and improve your listening accuracy.
There are several different activities that focus on test preparation, vocabulary, grammar, and sentence structure.
Es importante leer el vocabulario antes de ver el video. Esto mejorará su capacidad para comprender el video. También le ayudará a comprender cómo se usa el nuevo vocabulario de forma natural.
La primera vez que vea el video, intente comprender la situación general.
Primero intente responder todas las preguntas de memoria. Luego, vuelva a ver el video e intente responder las preguntas que se perdió.
Mire el video nuevamente mientras lee el guión. Leer y escuchar al mismo tiempo lo ayudará a escuchar cada palabra individual y mejorará su precisión auditiva.
Hay una serie de actividades diferentes que se centran en la preparación de la examen, el vocabulario, la gramática y la estructura de las oraciones.
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비디오를 처음 볼 때 전체 상황을 이해하려고 노력하세요.
먼저 모든 질문에 답을 해보세요. 그런 다음 비디오를 다시보고 놓친 질문에 답해보세요.
대본을 읽는 동안 비디오를 다시 보세요. 읽기와 듣기를 동시에 하면 각각의 단어를 듣고, 듣기 정확도를 향상시킬 수 있습니다.
듣기 정확도, 발음, 어휘, 문법 및 문장 구조에 초점을 맞춘 다양한 액티비티가 있습니다.
[n] - noun, [v] - verb, [phv] - phrasal verb, [adj] - adjective, [exp] - expression
Now let's celebrate the elements.
As many will remember from school chemistry lessons, the elements are all neatly set out in the periodic table - rhe brainchild of the Russian chemist Dimitri Mendeleev, who first drew it up 150 years ago.
Our science correspondent Helen Briggs told me more about the periodic table and why it's special.
Chemists see this periodic table as a thing of beauty and also a thing of usefulness because by reading it you can understand the properties of different elements. But if you cast your mind back to the day of Mendeleev 150 years ago, there were only about 60 known elements. There are now more than 100.
And people have been trying to arrange them for some time. But he had this leap of ingenuity in that he arranged them in a table mainly by their atomic mass. But he put them in groups in terms of those with similar properties, and he left gaps for new elements to be slotted in. And this was before we knew anything about the structure of the atom and all of these things that we now know.
So it was an amazing development. He wasn't the first to do it but he had this leap of ingenuity. And the periodic table today, it has changed but it's still really the same basis from a 150 years ago.
And I looked at the periodic table when I was at school. My son is doing that at the moment. It's still used to teach millions of people across the world, isn't it?
That's right. Generations of schoolchildren have had to learn this periodic table and understand. And it's not really just about rote learning, it's about understanding what's the basis behind it.
And now we've got 118 elements, and they're arranged in these in groups. The vertical columns but also in period - so seven periods. So we've got now seven periods complete and there could be more.
That was Helen Briggs our science correspondent. And if you go to the UNESCO website, you can watch a whole lot of talks and debates about that periodic table including a lecture by Ben Bringa, the 2019 Nobel Prize winner in chemistry.