The octave: 2 to 1八度:2 比 1
The combined wave repeats 220 times a second, as fast as the lower note itself.
疊起來的波每秒重複 220 次,和低音本身一樣快。
Music · Unit 2 · Lesson 8 · 音樂 單元二 第八課
Play two notes at once and see their waves line up. Hear the beats when two notes are almost the same, and build major and minor chords with three keys.
讓兩個音同時響,看它們的波怎麼對齊。聽兩個幾乎相同的音發出的拍音,再用三個鍵組出大三和弦與小三和弦。
When two notes sound together, a simple frequency ratio makes the combined wave repeat quickly, and many listeners hear that as blended. Notes that are almost, but not exactly, the same make beats. Three notes stacked in thirds make a chord.
兩個音同時響時,簡單的頻率比會讓疊起來的波很快重複,許多人聽起來就覺得融在一起。幾乎相同、但不完全相同的音會產生拍音。三個音按三度疊起來,就是和弦。
Try It · 動手試試
The lower note is always 220 Hz. Choose an interval, then press “Together” to hear both notes at once. The top wave is the lower note, the middle one is the upper note, and the bottom one is what you get when they are added together. Dashed lines mark where the combined wave starts to repeat. Then move the slider to mistune the upper note, and watch the loudness rise and fall: those are beats.
下面的音一律是 220 赫茲。選一個音程,再按「一起響」同時聽兩個音。最上面的波是低音,中間是高音,最下面是兩者疊在一起的結果。虛線標出疊起來的波從哪裡開始重複。再移動滑桿,把高音調歪,看音量一起一伏:那就是拍音。
Reading · 英文閱讀
An interval is the difference in pitch between two sounds. You can also say it as a frequency ratio. Two notes an octave apart have a ratio of 2 to 1. A perfect fifth is 3 to 2, a perfect fourth is 4 to 3, a major third is 5 to 4, and a minor third is 6 to 5. You met 2 to 1 and 3 to 2 on the string in lesson 1.
An interval’s name counts the notes it covers, with both ends included. From C to E is a third, because C, D, and E are three notes. In semitones, a minor third is 3, a major third is 4, a perfect fourth is 5, and a perfect fifth is 7. A perfect fifth is at the start of “Twinkle, Twinkle, Little Star.” A piano is not exactly in these ratios: its fifth is 700 cents, but 3 to 2 is about 701.96 cents, and its major third is about 14 cents wider than 5 to 4.
Musicians call a stable combination of notes a consonance, a point of rest. They call a tense combination a dissonance, which seems to want to move on. Consonance is often associated with simple ratios. Look at the lab: when two notes are an octave apart, the combined wave repeats as fast as the lower note. For a fifth it lines up again every 1/110 of a second. For a half step the pattern takes much longer, and the two notes seem to rub against each other.
When two notes are almost the same, you hear something else. The sound gets louder and softer, again and again, and this is called beats. The beat rate is the difference between the two frequencies: 220 Hz and 224 Hz make 4 beats per second. Slow beats are heard as the loudness changing, and faster ones, above about 20 per second, as a rough, fluttering sound. Piano tuners listen for beats to know when two strings are in tune. These beats are not the beat of a song, which you learned about in lesson 3.
A chord is two or more notes sounding at the same time. A triad has three notes stacked in thirds: the root, then a third above, then a fifth above. A major triad is a major third and a perfect fifth above the root, so from C it is C, E, G. In just intonation its ratio is 4 : 5 : 6. A minor triad has a minor third instead, so from C it is C, E♭, G. Only the middle note is different, by one half step. Major and minor triads are the most common triads in Western music.
Is the pleasure of consonance built in, or learned? Researchers still debate it. In a 2016 study, people of the Tsimane’, an Amazonian society with little exposure to Western music, rated consonant and dissonant chords as equally pleasant. But they still disliked rough sounds. Dissonance is not simply bad, either. Dissonances often play a decisive role in making music pleasant. So listen with open ears, and let your own listening tell you what you find beautiful.
Questions · 閱讀理解
Why is the interval from C to E called a third?
What do you hear when you play 220 Hz and 224 Hz together, and how fast is it?
What is the difference between a major triad and a minor triad?
Words & Phrases · 生字及片語
Quick Check · 小測驗
1. What is the frequency ratio of a perfect fifth, in the simple (just) form?
2. How many semitones are in a major third?
3. What do you hear when two notes are almost, but not exactly, the same frequency?
4. How does a minor triad differ from a major triad?
5. A C major triad is C E G. How many semitones is G above C?
Try It in the Model · 在模型裡試試
Then try it yourself: choose the unison and drag the slider slowly. When does the pulsing slow down and stop?
然後自己試試:選同度,慢慢拖動滑桿。起伏什麼時候變慢、停下來?
The combined wave repeats 220 times a second, as fast as the lower note itself.
疊起來的波每秒重複 220 次,和低音本身一樣快。
Two waves line up again every 1/110 of a second. Look at the dashed lines.
兩個波每 1/110 秒重新對齊一次。看看虛線。
The pattern repeats only about 15 times a second, and the two notes rub against each other.
圖樣每秒只重複約 15 次,兩個音彼此摩擦。
The upper note is mistuned a little. The loudness swells and fades, again and again.
高音被調歪了一點。音量一次又一次地變大、變小。
Build It · 動手組組看
Press three keys, and the page tells you what chord they make. Try C E G, then lower the E by one key. What changed?
按三個鍵,頁面會告訴你它們組成什麼和弦。試試 C E G,再把 E 降低一個鍵。有什麼改變?
Game · 小遊戲
Six questions. Each one plays a triad. Choose major or minor. If you cannot hear the sound, press “Show the notes” and look at how far the middle note is above the lowest one.
六道題。每一題播放一個三和弦。選大三和弦或小三和弦。如果聽不到聲音,按「看音」,看中間的音比最低音高幾個半音。
Question 1 of 6 · 第 1 題(共 6 題)
Right on the first try · 第一次就答對 0 / 0
Stories Behind the Notes · 音符背後的故事
Four short stories about how people have thought about sounds that go together.
關於人們怎麼看待一起響的聲音的四個小故事。
A Name · 名字
Perfect intervals, such as the fourth, fifth, and octave, are called perfect because they were traditionally considered perfectly consonant. Taiwan’s standard translations use the word 完全, as in 完全五度, for perfect fifth. The name does not mean that every other interval is imperfect, or that a perfect interval is always the best choice.
完全音程,例如四度、五度和八度,叫「完全」,是因為傳統上它們被認為是完全協和的。台灣的標準譯名用「完全」兩個字,例如 perfect fifth 是完全五度。這個名字不表示其他音程就是不完美,也不表示完全音程永遠是最好的選擇。
A Legend · 一個傳說
According to legend, Pythagoras heard blacksmiths’ hammers ringing and discovered that musical notes could be turned into numbers. But no authentic writings of Pythagoras survive, and modern scholars usually ascribe these discoveries to the later Pythagorean Philolaus. The tuning built from fifths is named after Pythagoras, but its system dates back to ancient Mesopotamia.
依傳說,畢達哥拉斯聽到鐵匠的錘子敲擊聲,發現音可以變成數字。但畢達哥拉斯本人沒有留下可靠的著作,現代學者通常把這些發現歸給後來的畢達哥拉斯學派的菲洛勞斯。用五度疊出來的音律以畢達哥拉斯命名,但這個系統可以追溯到古代美索不達米亞。
A Rough Sound · 粗糙的聲音
Beats are not always a mistake. Many pipe organs have “celeste” stops that intentionally produce beating, and in some musical traditions people consider the rough, fluttering sound an attractive part of the timbre. Whether a sound is pleasant depends on the style of music and the listener.
拍音不一定是錯誤。許多管風琴有「天使音栓」(celeste),故意製造拍音;有些音樂傳統認為,這種粗糙、顫動的聲音是迷人的音色的一部分。一個聲音好不好聽,要看音樂的風格與聽的人。
Different Ears · 不同的耳朵
In a 2016 study published in Nature, the Tsimane’, a native Amazonian society with minimal exposure to Western culture, rated consonant and dissonant chords and vocal harmonies as equally pleasant. They did show Western-like dislike for acoustic roughness. Bolivian town and city dwellers preferred consonance, less strongly than US residents did. The authors concluded that culture has a dominant role in shaping these responses, and other researchers still argue for a biological part.
2016 年發表在《自然》期刊的一項研究中,奇曼內人(Tsimane’,亞馬遜地區、很少接觸西方文化的原住民社群)認為協和與不協和的和弦與人聲和聲同樣悅耳;但他們和西方人一樣不喜歡粗糙的聲音。玻利維亞城鎮的居民比較喜歡協和,程度比美國居民輕。作者的結論是文化在塑造這些反應上占主導地位;也有其他研究者主張其中有生物性的成分。
In the Curriculum · 對應課綱
The curriculum names unison singing, rounds, part singing, and harmony. The words “interval,” “chord,” “triad,” “consonance,” and “dissonance” do not appear in the curriculum itself.
課綱寫到齊唱、輪唱、合唱和和聲。「音程」「和弦」「三和弦」「協和」「不協和」這些詞,課綱本文裡沒有出現。
音 E-Ⅱ-1藝術領域・音樂(國小三、四年級) · Arts, music (grades 3–4)
多元形式歌曲,如:獨唱、齊唱等。
In unison singing, everyone sings the same note. That is a ratio of 1 to 1.齊唱時大家唱同一個音,頻率比是 1 比 1。
音 E-Ⅲ-1藝術領域・音樂(國小五、六年級) · Arts, music (grades 5–6)
多元形式歌曲,如:輪唱、合唱等。
In rounds and part singing, different notes sound together.輪唱與合唱時,不同的音會同時響。
音 E-Ⅳ-4藝術領域・音樂(國中七至九年級) · Arts, music (grades 7–9)
音樂元素,如:音色、調式、和聲等。
Harmony is first named as a musical element in junior high school.和聲在國中才第一次被列為音樂元素。
音 A-Ⅳ-2藝術領域・音樂(國中七至九年級) · Arts, music (grades 7–9)
相關音樂語彙,如音色、和聲等描述音樂元素之音樂術語,或相關之一般性用語。
Words for describing harmony are part of musical vocabulary.描述和聲的詞彙,屬於音樂語彙。
Myth vs. Fact · 常見迷思
✗ Myth · 迷思Dissonant means bad.不協和就是不好聽。
✓ Fact · 事實A dissonance is a tension that wants to move on. Dissonances often play a decisive role in making music pleasant.不協和是一種想要往前走的緊張。不協和常常是讓音樂悅耳的關鍵。
✗ Myth · 迷思A piano plays exactly 3 to 2 for a fifth.鋼琴彈出的五度就是剛好 3 比 2。
✓ Fact · 事實A piano’s fifth is 700 cents, and 3 to 2 is about 701.96 cents. It is very close, but not the same. Its major third is about 14 cents wider than 5 to 4.鋼琴的五度是 700 音分,3 比 2 約是 701.96 音分,非常接近,但不完全一樣。它的大三度比 5 比 4 寬約 14 音分。
✗ Myth · 迷思Everyone hears consonance the same way.每個人聽到的協和都一樣。
✓ Fact · 事實Researchers still debate how much is built in and how much is learned. One study found a group who rated consonant and dissonant chords as equally pleasant.研究者還在爭論有多少是天生的、有多少是學來的。有一項研究發現,有一個社群認為協和與不協和的和弦同樣悅耳。
✗ Myth · 迷思Pythagoras discovered the ratios from blacksmiths’ hammers.畢達哥拉斯是聽鐵錘發現比例的。
✓ Fact · 事實That is a legend. No authentic writings of Pythagoras survive, and scholars usually ascribe the discoveries to Philolaus.那是傳說。畢達哥拉斯沒有留下可靠的著作,學者通常把這些發現歸給菲洛勞斯。
Remember It · 記憶口訣
2:1, 3:2, 4:3: the combined wave lines up often.
2:1、3:2、4:3:疊起來的波常常對齊。
The beat rate is the difference in frequency.
拍音的速度就是頻率的差。
C E G: stack every other note of the scale.
C E G:每隔一個音疊一個。
Count the half steps from the root.
從根音開始數半音。
Protect Your Ears · 保護耳朵
Classroom Activity 1 · 課堂活動一
You need · 準備材料
Steps · 步驟
Singing in tune with another voice is hard at first, so let students try several times and praise the effort. Stay in a comfortable range.
一開始要和別人唱得準很難,讓同學多試幾次,肯定他們的努力。待在舒服的音域裡。
Classroom Activity 2 · 課堂活動二
You need · 準備材料
Steps · 步驟
Accept every honest description. The activity is not a test of the “right” feeling.
每個誠實的形容都接受。這個活動不是在測驗「標準」的感覺。
Go Further · 延伸閱讀
Sources · 資料出處
Names, numbers, and quotations on this page were checked against these sources (October 2026). The waves, ratios, and chords are computed by the page itself and covered by automatic tests. · 本頁的名稱、數字與引文依下列資料查證(2026 年 10 月);波形、比例與和弦由頁面自己計算,並有自動測試。