ฝึกพูดภาษาอังกฤษด้วยเทคนิค Shadowing จากวิดีโอ: Material Properties 101

กำลังสร้างบทเรียน...
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This video is going to be a bit different to my usual videos, but I want to talk about material properties and the words we use to describe them.
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This is information you are going to need to fully understand future videos.
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By the end of this video, I want you to understand 6 keywords that we use to describe materials.
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These are stiff, strong, ductile, brittle, tough and hard.
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With these words, you will be able to describe pretty much any material
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and better understand why certain materials are used in different applications.
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More technical videos like this will be uploaded to my second channel from now on, which you can subscribe to by following this link.
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I'll try and back up the technical stuff with interesting real-world examples.
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First we are going to learn what a tensile test is.
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A tensile test is a fundamental test in material mechanics.
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It's performed by pulling a sample of material apart until failure, while measuring the force and displacement.
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It provides us with something called a stress strain curve, which tells us a lot about the material's reactions to forces.
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In this scenario, the stress is defined by the force applied to the test sample, divided by the cross-sectional area.
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This gives us units of newtons per meter squared, which you may recognize as the metric unit for pressure, Pascals.
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Stress goes on the y-axis.
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Strain describes how much deformation has occurred with that applied force, and it is found by dividing the change in length by the original length.
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This is placed on the x-axis.
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Let's watch this test again and see what information we can get from the stress strain graph.
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As the stress rises, the material begins to deform.
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This initial linear region is elastic deformation, That means if we remove the force, the material will regain its original shape.
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Think of how a rubber band can deform hugely and still come back to its original shape.
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The end of this linear elastic deformation is marked by the yield point.
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From here out, any additional stress will cause permanent deformation.
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This is called plastic deformation.
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The stress continues to rise until it hits the ultimate tensile strength point.
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This is the ultimate strength of the material, the most stress it can handle.
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From here, less stress is needed as the material begins to decrease in cross section, which you can see happening here.
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This is called necking.
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This continues until the material fractures.
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We can get a lot of really useful information from this graph.
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The first is Young's modulus, otherwise known as the elastic modulus.
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This describes how stiff the material is, and it is obtained by finding the slope of this linear region.
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A steeper slope means a stiffer material.
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For example, a high carbon steel may look like this, whereas a flexible material with the low Young's modulus, like rubber, would look like this.
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This graph is not to scale, but it should give you an idea of how this information is represented.
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Young's modulus is one of the most used properties in engineering, as we can use it to predict deflection in a huge range of scenarios.
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Yield strength and ultimate tensile strength are two other important properties.
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An engineer will divide the yield or ultimate strength by the safety factor to achieve the max allowable stress, which is used to influence the design of the product.
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Usually engineers will aim to keep the max possible stress well below failure, but safety factors differ between industries.
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So we've seen a stiff material and a flexible material.
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Now let's look at a material in between.
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This material can be described as tuff and ductile.
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Tuff simply means the material can absorb a lot of energy without breaking.
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The area under the graph here defines how much energy is absorbed.
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Ductile means it deforms under pressure.
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The two previous materials could also be considered ductile.
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Springsteel is a tough and ductile material with a high yield strength which is why it is used in springs.
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Springs need to absorb energy without permanently deforming.
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The opposite of ductile is brittle.
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A brittle material is a material that breaks with very little deformation.
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Glass, ceramics and cast iron all fall into this category.
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You can actually tell if a material is brittle or ductile by examining the fracture surface after they have broken.
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A ductile material will have this characteristic cup and cone fracture surface, whereas brittle fractures have granular flat looking fracture surfaces.
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Some materials can go from ductile to brittle when their temperatures are lowered.
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This was actually a massive problem during World War 2 with the Liberty ship.
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Several Several of these ships literally broke in half with no warning, including the SS John P.
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Gaines, which broke in half in the frigid waters of the Bering Sea.
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It was later discovered that the grade of steel being used became brittle at lower temperatures.
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This problem was made worse by the stress concentration at the hatches, which you learned about in my first video, Why are plane windows round?
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This embrittlement is also thought to have contributed to the fracture of the titanic's hull.
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The final material property I want to talk about is hardness.
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It is directly related to the stiffness and yield strength of the material, but it is used to describe how difficult it is to dent, scratch and abrade materials.
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One way this material property is measured is with the Rockwell hardness test.
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This test involves three steps.
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First a minor load is applied to the material by an indenter.
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This establishes a zero point.
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For the second step, a major load is then added, which indents the material.
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And for the final step, the major load is removed, while maintaining the initial load.
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The difference in depth between the first and third step is then used to calculate the hardness of the material.
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Diamond is a very hard material, which is why it is used in cutting tools.
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One of the fantastic properties of steel is its ability to be heat treated, to have its hardness tailored in different areas.
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For example, with swords you want your cutting edge to be hard but the core of the blade to be ductile.
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This means the sword can bend under pressure without breaking, while the cutting edge can resist damage.
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As always, thanks for watching.
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คำศัพท์และข้อสังเกตด้านการพูดสำหรับบทเรียนนี้

บทเรียนฝึกพูดระดับ C1 นี้ใช้วิดีโอ “Material Properties 101” เป็นสื่อ คำที่ถูกพูดซ้ำบ่อยที่สุด: material, stress, ductile, brittle, strength วิดีโอนี้มี 85 ประโยค และ 1264 คำ สำหรับฝึกพูดตาม ช่วงที่มีเสียงพูดยาว 6:06 ผู้พูดพูดเร็ว ประมาณ 207 คำต่อนาที จึงมีการเชื่อมเสียงและลดเสียงค่อนข้างมาก 82% ของคำอยู่ใน 3,000 คำที่ใช้บ่อยที่สุดในภาษาอังกฤษ ส่วนที่เหลือควรดูไว้ก่อนเริ่มฝึก

คำศัพท์สำคัญในวิดีโอนี้

คำที่ยากที่สุด 15 คำในวิดีโอ พร้อมคำอ่านและความหมาย:

คำศัพท์คำอ่านความหมาย
fracture คำนาม/ˈfɹæk.t͡ʃʰəː/กระดูกหัก
hardness คำนาม/ˈhɑɹdnəs/ความแข็ง
stiff คำคุณศัพท์/stɪf/แข็ง
graph คำนาม/ɡɹæf/กราฟ
elastic คำคุณศัพท์/ə-/ยืดหยุ่น
absorb คำกริยา/æbˈsɔɹb/ดูดซับ
axis คำนาม/ˈæksɪs/แกน
tailor คำนาม/ˈteɪlɚ/ช่างตัดเสื้อ
dent คำนาม/dɛnt/รอยบุ๋ม, รอยบุบ
ceramic คำนาม/səˈɹæmɪk/เซรามิก
metre คำนาม/ˈmiːtəɹ/เมตร
mechanic คำนาม/mɪˈkænɪk/ช่างเครื่อง
hatch คำกริยา/hæt͡ʃ/ฟัก
cone คำนาม/ˈkoʊn/กรวย
calculate คำกริยา/ˈkælkjʊleɪt/คำนวณ

ไวยากรณ์ในวิดีโอนี้

โครงสร้างที่ผู้พูดใช้บ่อยที่สุด พร้อมคำพูดจริงจากวิดีโอ:

โครงสร้างในวิดีโอ
Passive voice be + กริยาช่อง 3 — เน้นสิ่งที่เกิดขึ้น ไม่ใช่ผู้กระทำwill be uploaded · is defined · is found
Present perfect have/has + กริยาช่อง 3 — เหตุการณ์ในอดีตที่ยังเกี่ยวข้องกับปัจจุบันhas occurred · we've seen · have broken
Relative clauses who / which + อนุประโยค — ข้อมูลเพิ่มเติมเกี่ยวกับคนหรือสิ่งของstress, which is · strength which is · material, which is

การออกเสียงที่ควรระวัง

ผู้พูดใช้รูปย่อและรูปลดเสียง 3 ครั้ง เช่น I'll, we've, wouldn't ให้พูดแบบสั้นตามที่ได้ยิน

  • เสียง “sh” และ “zh”: deformation /ˌdɛfəˈmeɪʃən/, deflection /dəˈflɛkʃən/, sectional /ˈsɛkʃənəl/, consultation /ˌkɑnsəlˈteɪʃən/
  • คำยาว — ลงเสียงหนักให้ถูกพยางค์: deformation /ˌdɛfəˈmeɪʃən/, allowable /əˈlaʊ.əbəl/, personalize /ˈpɜː.sə.nə.laɪz/, characteristic /ˌkæɹ(ə)ktəˈɹɪstɪk/, consultation /ˌkɑnsəlˈteɪʃən/

เสียงที่คนไทยมักออกเสียงยาก:

  • เสียงท้ายคำ — ออกเสียงให้ครบ ไม่เปลี่ยนเป็นตัวสะกดแบบไทย: distress /dɪˈstɹɛs/, ductile /ˈdʌk.təl/, brittle /ˈbɹɪtəl/, hardness /ˈhɑɹdnəs/, modulus /ˈmɑdʒələs/
  • /r/ กับ /l/ — แยกให้ชัด: brittle /ˈbɹɪtəl/, embrittlement /ɛmˈbɹɪtl̩mənt/, granular /ˈɡɹæn.jə.lə(ɹ)/, counselor /ˈkaʊnsələ(ɹ)/
  • พยัญชนะควบ — ออกเสียงให้ครบทุกตัว: distress /dɪˈstɹɛs/, brittle /ˈbɹɪtəl/, fracture /ˈfɹæk.t͡ʃʰəː/, deform /dəˈfɔɹm/, hardness /ˈhɑɹdnəs/

วิธีฝึกกับวิดีโอนี้

  1. ฟังวิดีโอให้จบหนึ่งรอบโดยยังไม่ต้องพูด แล้วจดคำที่ยังไม่รู้จัก
  2. เริ่มที่ความเร็ว 0.75× พูดตามทีละประโยค แล้วกลับไปใช้ความเร็วปกติเมื่อเริ่มคล่อง
  3. อัดเสียงตัวเองแล้วเทียบกับต้นฉบับ โดยสังเกตคำอย่าง fracture, hardness, stiff เป็นพิเศษ

เทคนิค Shadowing คืออะไร?

Shadowing เป็นเทคนิคการเรียนรู้ภาษาที่ได้รับการรับรองทางวิทยาศาสตร์ พัฒนาขึ้นสำหรับการฝึกนักแปลมืออาชีพ วิธีการนี้เรียบง่ายแต่ทรงพลัง: คุณฟังเสียงภาษาอังกฤษจากเจ้าของภาษาและพูดตามทันที — เหมือนเงาที่ตามผู้พูดด้วยช่วงเวลาห่าง 1-2 วินาที การวิจัยแสดงว่าเทคนิคนี้ปรับปรุงความแม่นยำในการออกเสียง ทำนองเสียง จังหวะ การเชื่อมเสียง การฟังเข้าใจ และความคล่องแคล่วในการพูดได้อย่างมีนัยสำคัญ

เทคนิค shadowing: อ่านคู่มือฉบับเต็มทีละขั้นตอน →