4 Z 4, pp. 333∼337

 4 Z 4, pp. 333∼337

z

º‘ ¨ Ý­ Ž' [O  W ² Žõ u § T “ Ó Þ” X ¢ “ Ö ¨’ Ò ×• ¤X N Ë ÷ m Ç] M öX ê sV  4 ®  o

† ç

¡: c^ ï B · + ä  * > * å 

ô

 Dz D G “ §" é ¶ @ /† < Ɠ § Ó ü t o “ §¹ ¢ ¤ õ , Ø  æ· ¡ ¤ ' õ A" é ¶ 363-791 (2009¸   12 Z 4 22{ 9  ~ à Î6 £ §, þ j7 á x à º& ñ ‘ : r 2010¸   3 Z 4 5{ 9  ~ à Î6 £ §)

‘ :

r ƒ  ½ ¨\ " f  H ATmega8535  s ß ¼– І à Ô\  ¦  Q\  ¦  6   x ô  Ç – Ð4 Ÿ © Û ¼' n  v à Ôü <  s ß ¼ ¿ º > h\  ¦ s 6   x

# Œ $ § 4  “ ¦ › ¸w n  l  / 'î  r 6 £ §5 Å q8 £ ¤& ñ  © œu \  ¦ > hµ 1 Ï % i  . 6 £ §   ¿ º  s ß ¼  s \  ¦ ”  ' Ÿ    H r ç ß –

\  ¦ 8 £ ¤& ñ % i Ü ¼ 9 ] j Œ •õ  á Ԗ ÐÕ ªA b ç s  # Q§ > t  · ú §“ ¦, LCD– Ð   õ \  ¦ 7 £ ¤ r  ^  ¦ à º e ” # Q z  ´+ « > õ & ñ s  ç ß

–é ß –  . l ^ ‰, “ ¦^ ‰, Ó  o^ ‰ B | 9 \ " f_  6 £ §5 Å q`  ¦ 8 £ ¤& ñ % i “ ¦, > hµ 1 Ïô  Ç  © œu _  ‰ & ³ © œ& h 6   x 0 p x$ í `  ¦ › ¸  ô

 Ç   õ  F N& ñ & h s % 3  .

Ù þ

˜d ” # Q: 6 £ §5 Å q8 £ ¤& ñ , ATmega8535, MBL

Development of an Instrument to Measure the Speed of Sound by Using the Robotstudy Kit

Se Jung Jang ^∗ · Min Young Jeong

Department of Physics Education, Korea National University of Education, Chungbuk Cheongwon 363-791 (Received 22 December 2009, in final form 5 March 2010)

We developed an inexpensive and easy-to-use instrument to measure the speed of sound by using the following Robotstudy kit components: ATmega8535 and two microphones. The advantages of this apparatus are readily available parts, case of easy assembling to make, simple programming for operation, and real-time display of results. This instrument measures the travel time of sound pulses between the two microphones. We measured the speed of sound waves in various media, such as gases, solids, and liquids, by employing this instrument. It’s applicability to the middle-school and the high-school curricula was investigated, and the results were affirmative.

PACS numbers: 01.50.Pa

Keywords: Sound speed, 8535, MBL

I. " e  ] Ø

/ B

N l  ×  æ _  6 £ §5 Å q“ É r 340 m/s – Ð · ú ˜ 94 R e ”  . s  6 £ §5 Å q

`

 ¦ 8 £ ¤& ñ   H ~ ½ ÓZ O Ü ¼– Ð V , o  · ú ˜ 9”    כ “ É r l Å Ò/ B N" î  © œu 

 ñ  H à Ô › ' a`  ¦ s 6   x ô  Ç z  ´+ « >Ü ¼– Ð, { 9 & ñ ô  Ç ”  1 l x à º_  6 £ §" é ¶`  ¦



6   x # Œ / B N" î s  { 9 # Q± ú ˜ M :_   o \  ¦ 8 £ ¤& ñ “ ¦, s – РÒ

∗

E-mail: [email protected]

'

 6 £ §  _    © œ`  ¦ ½ ¨ô  Ç  6 £ § ”  1 l x à ºü <   © œ`  ¦ Y  L # Œ 5 Å q

§ 4

`  ¦ · ú ˜  · p .

Õ

ª  X <, s  ~ ½ ÓZ O “ É r r ç ß –• ¸ ´ ú §s    o “ ¦ 8 £ ¤& ñ ~ ½ ÓZ O `  ¦ s  K

   H  כ s  ~ 1 t  · ú § . s ü <   É r ~ ½ ÓZ O Ü ¼– Ð q ' Ÿ r ç ß – 8 £ ¤

&

ñ Z O s  e ”   H X <, s  ~ ½ ÓZ O “ É r ×  æ † < Ɠ § † < ÆÒ q t• ¸ ~ 1 >  s K ½ + É Ã º e ”

  H ~ ½ ÓZ O Ü ¼– Ð [1] ` O Û ¼ ¿ º t & h `  ¦ t 
° ú ˜ M : r ç ß –`  ¦ 8 £ ¤

&

ñ “ ¦ [2–4], ¿ º t & h   s _   o \  ¦ s 1 l x   H X <    2 ; r

ç ß –Ü ¼– Ð
¾ º# Q 6 £ §5 Å q`  ¦ > í ß –ô  Ç .

/ B

N l _  6 £ §5 Å q`  ¦ 8 £ ¤& ñ   H  כ ˜ Ð  “ ¦^ ‰, Ó  o^ ‰_  6 £ §5 Å q`  ¦

-333-

Fig. 1. The structure of measuring the sound velocity.

8

£ ¤& ñ   H  כ “ É r  8 # Q§ > l  M :ë  H \  Ó ü t o “ §¹ ¢ ¤ › ' aº   † < ÆÕ ü t t 

\

  H ô  Ç t  ¢ ¸  H ¿ º t  B | 9 \  @ /K " fë ß – z  ´+ « > ~ ½ ÓZ O s  ]

jr ÷ &  H  â Ä º ´ ú §Ü ¼ 9 [1–11], Ó  o^ ‰\  @ /ô  Ç z  ´+ « >“ É r [11]



_  ] jr ÷ &# Q e ” t  · ú §  l ^ ‰, “ ¦^ ‰, Ó  o^ ‰ B | 9  — ¸¿ º_  6

£

§5 Å q`  ¦ 8 £ ¤& ñ ½ + É Ã º e ”   H  © œu \  ¦ > hµ 1 Ͻ + É € 9 כ ¹ e ”  .

Ä

ºo 
 \   H “ §¹ ¢ ¤6   x Ü ¼– Ð ˜ Ð/ å L ) a # Œ Q – Ð4 Ÿ © v à Ô

 e ”   H X < Õ ª ×  æ \   s ß ¼– Ð † à Ô\  ¦  Q(MCU)– Ð AT- mega8535\  ¦  6   x   H – Ð4 Ÿ © v à Ô\  ¦ ~ 1 >  ½ ¨{ 9 ½ + É Ã º e ”  Ü

¼ 9 [12], s  v à Ô_   © œ& h “ É r Ú ÔY U× ¼˜ Ð× ¼ ] j/ B N ÷ &Ù ¼– Ð G '

p" f  r– Ð\  ¦ ± ú šÛ  r\ O s  › ¸w n ½ + É Ã º e ”    H & h s  . K { © œ

“

§F \  ¦ s K  # Œ – Ð4 Ÿ © v à Ô\  ¦ ë ß –[ þ t & ñ • ¸€   8 £ ¤& ñ   õ \  ¦ LCD – Ð
 è ­ q à º e ”   H MBL  © œu \  ¦ ç ß –é ß –y  ] j Œ •½ + É Ã º e ”

Ü ¼ 9 á Ԗ ÐÕ ªÏ þ ›• ¸  Œ •$ í ½ + É Ã º e ”  .

II. X ê sV  < gX c l

Fig. 1“ É r / B N l ü < ^ o =  H _  6 £ §5 Å q`  ¦ 8 £ ¤& ñ l  0 Aô  Ç  © œu s 



. G ' p" f– Ѝ  H 6 £ §  \  ¦ à º’     H { 9  7 ˜à Ô! Á – B HD ! p" f  s ß ¼ MK754 ¿ º > h\  ¦  6   x % i Ü ¼ 9,  s ß ¼ ’    ñ\  ¦ n t _ O  o

l  0 Aô  Ç q “ §l – Ѝ  H ƒ  í ß – 7 £ x; Ÿ ¤ l  HA17358`  ¦ s 6   x 

%

i Ü ¼ 9 – Ð4 Ÿ © v à Ô_  Ú ÔY U× ¼˜ Ð× ¼0 A\  › ¸w n  % i  .

Fig. 2(a)  H  s ß ¼– Ð Ã º’   ) a ’    ñ\  ¦ š ¸z  ´– ÐÛ ¼ ïá Ô\ 

"

f ‘ : r — ¸€ ª œs  9 Fig. 2(b)  H à º’   ) a ’    ñ q “ §l \  _  K

 0 V ¢ ¸  H 5 V _  n t _ O  ’    ñ– Ð   ¨ 8 Š ) a — ¸€ ª œs  .

ATmega8535   H ' Í   P : n t _ O  ’    ñ_   © œ5 p x ¢ ¸  H y © œ r

y Œ •`  ¦ B j— ¸o \  l 2 Ÿ ¤   H X <, r y Œ •“ É r 8 MHz _  ß ¼o Û ¼

»

1 Ï`  ¦ æ ¼l  M :ë  H \  ¼ 1 ÏÑ þ ˜ë ß – ì  r _  { 9 œ í é ß –0 A– Ð 8 £ ¤& ñ s  0 p x

 . l ^ ‰ü < “ ¦^ ‰\ " f  H y © œ r y Œ •`  ¦ 8 £ ¤& ñ % i “ ¦ Ó  o^ ‰

\

" f  H  © œ5 p x r y Œ •`  ¦ 8 £ ¤& ñ % i  . s  M : [ O & ñ ô  Ç q “ §l _  à

Ôo   Y U6 \ š“ É r 20 mV – Ð" f Šҁ  _  ¸ ú š6 £ § s  Á ºr ÷ &• ¸2 Ÿ ¤ z 

´+ « >\  _ K    & ñ  ) a ° ú כs  .

Fig. 3“ É r  s ß ¼ü < q “ §l _   r– Е ¸s  . MIC1 ’    ñ



 H q “ §l \  ¦  5 g n t _ O  o  ) a ’    ñ\  ¦ ATmega8535 _  Ÿ í

Fig. 2. Analog signal conversion to digital signal.

Fig. 3. The microphone circuit.

à

Ô D_  2   — 2 ;(PD.2)\  { 9 § 4 r v “ ¦ MIC2• ¸ ¿ º   P : q 

“

§l \  ¦  5 g PD.3\  { 9 § 4 r (   . y Œ • Ÿ íà Ԗ Ð [ þ t # Qš ¸  H ' Í

’

   ñ_  r ç ß – \  ¦ > í ß –  9,  s ß ¼  s _   o   H á Ԗ Ð Õ

ªÏ þ ›\  { 9 § 4 ÷ &# Q e ” Ü ¼Ù ¼– Ð 6 £ §5 Å q`  ¦ Fig. 4 _  LCD o€  \ 

Fig. 4. The robotstudy kit.

Fig. 5. The flow chart.

˜

Ð# ŒÅ ҍ  H  כ % ƒ! 3   – Ð
 è ­ q à º e ”  .

Fig. 4  H – Ð4 Ÿ © v à Ô\  ¦ s 6   x K  ] j Œ •ô  Ç 6 £ §5 Å q 8 £ ¤& ñ z  ´+ « >



© œu – Ð" f v à Ô\  ¦  6   x t  · ú §“ ¦, y Œ •  Ҿ ¡ §`  ¦ ë ß –0 p x l ó ø Í\  f ”

] X  ] j Œ • €  , 6 £ §5 Å q 8 £ ¤& ñ  © œu \  ¦  8 $ § 4  >  ] j Œ •½ + É Ã º e ”

 .

Fig. 5  H á Ԗ ÐÕ ªÏ þ › í  H " f• ¸– Ð" f ô  Ç   _  8 £ ¤& ñ s  = å Q


€

  6 £ §5 Å q`  ¦ LCD \  Ø  ¦§ 4  “ ¦, @ /l   © œI – Ð [  t    r  PD.2 \  ’    ñ { 9 § 4 ÷ &  H í  H ç ß –, 8 £ ¤& ñ `  ¦ ì ø Í4 Ÿ ¤ • ¸2 Ÿ ¤ 

%

i Ü ¼ 9, z  ´] j á Ԗ ÐÕ ªA b ç “ É r / B N > h  ) a > hµ 1 ÏÚ  ¦ CodeVision AVR C\  ¦  6   x % i “ ¦,  © œu _   r– Е ¸ü < á Ԗ ÐÕ ªÏ þ ›“ É r “   '

 Å http://bbs.knue.ac.kr/∼3409/ \  / B N > h % i  .

/ B

N l ü < ^ o =  H _  6 £ §5 Å q“ É r ` O Û ¼\  ¦ ë ß –× ¼  H ~ ½ ÓZ O ë ß –  Ø Ô“ ¦

° ú

 “ É r  s ß ¼\  ¦  6   x % i   H X <, Ó ü t5 Å q _  6 £ §5 Å q 8 £ ¤& ñ `  ¦ 0 Aô  Ç



s ß ¼  H Ó ü t s  [ þ t # Qt  · ú §• ¸2 Ÿ ¤ > h› ¸ % i  .  s ß ¼   s

_   o   H B | 9     Ø Ôl  M :ë  H \  Ú ÔY U× ¼˜ Ð× ¼\ " f Û ¼ 0

Au \  ¦ › ¸ Œ • # Œ á Ԗ ÐÕ ªÏ þ ›s  ì  r l ÷ &• ¸2 Ÿ ¤ % i “ ¦, ì  r l \  ¦ 0

Aô  Ç Û ¼0 Au   H Fig. 3 õ  ° ú  s  Ÿ íà Ô D_  0  õ  1   — 2 ;\ 

ƒ

    % i  .

III. • ¤X N Ë õ m Í + s ÇÊ Ý

1. M = k8 ý “ Ö ¨’ Ò ×



s ß ¼  s _   o   H 1 m – Ð “ ¦& ñ % i “ ¦, / B N l \  ¦ : Ÿ x K

 ”  ' Ÿ    H 6 £ §  _  q “ §l  ’    ñ\  ¦ ì  r$ 3 ô  Ç   õ  r ç ß –  s

  H 2908 µm s % 3 Ü ¼ 9, 100 r ì ø Í4 Ÿ ¤ z  ´+ « >   õ  8 £ ¤& ñ  ) a 6

£

§5 Å q“ É r v = 343 ± 2 m/s s % 3  . 2 m/s   H ³ ðï  r ¼ #  – Ð

"

f ¨ î ç  H \  @ /ô  Ç Ñ þ ˜ì  rÖ  ¦ – Ð 1 % s  s  . / B N l  ×  æ _  6 £ §5 Å q

\

 @ /ô  Ç › ' a > d ” “ É r d ” (1)õ  ° ú   .

v = r γRT

M (1)

#

Œl " f ㍠ H l ^ ‰ ]  t q \ P _  q Ö  ¦, R“ É r l ^ ‰ © œÃ º, T  H ] X 

@

/“ : r • ¸, M“ É r / B N l  1]  t _  | 9 | ¾ Ós  . { 9 ì ø Í& h Ü ¼– Ð > í ß –`  ¦ ç

ß –é ß –y  l  0 AK " f d ” (1)“ É r d ” (2) [8] ü < ° ú  s  “ : r • ¸_  † < Ê Ã

º– Ð ³ ð‰ & ³  9, s \  ¦ s 6   x # Œ / B N l  ×  æ _  6 £ §5 Å q`  ¦ > í ß –ô  Ç



. z  ´+ « >z  ´ “ : r • ¸ T

C

= 25

^◦

C { 9  M : 6 £ §5 Å q“ É r d ”  (2)\  _ 

€   v = 346.7 m/s – Ð  © œ@ /š ¸   H €  • 1 % s  .

v = 331.45 + 0.61T

C

(2)

2. w Š= k8 ý “ Ö ¨’ Ò × 4

Ÿ

x + þ AI _  ^ o =  H \ " f 6 £ §5 Å q“ É r d ”  (3)õ  ° ú  “ ¦, ì  r í ß –s  \ O 



“ ¦ & ñ % i Ü ¼ 9 [14], # Œl " f Y  H % ò Ò  ¦ s “ ¦ ρ  H x 9 • ¸ s

 .

v = s

Y

ρ (3)

Table 1“ É r ¿ º  s ß ¼  s _   o \  ¦ 2 m – Ð “ ¦& ñ “ ¦ [

j t  “ ¦^ ‰ B | 9 \  @ / # Œ y Œ •y Œ • 100 r z  ´+ « >ô  Ç   õ s 



. x 9 • ¸ €  • 7850 kg/m

²

, f ”  â 13 mm “   ^ o =  H _  6 £ §5 Å q“ É r v = 5076 ± 50 m/s – Ð 8 £ ¤& ñ ÷ &% 3  . 50 m/s   H ³ ðï  r¼ #  

–

Ð" f ¨ î ç  H \  @ /K  ¼ #   1 % s  % i  .

ü

@ â 26 mm, ? / â 20 mm, U  ´s  1 m “   PVC› ' a _  6 £ §5 Å q

“

É r v = 1564 ± 36 m/s – Ð 8 £ ¤& ñ ÷ &% 3 “ ¦, s  ° ú כ“ É r l ” > r _  8 £ ¤

&

ñ ° ú כ 1550 m/s ü < 0.9 % _   © œ@ /& h  s \  ¦ ˜ Ð% i “ ¦, t 2 £ § 30 mm, U  ´s  2 m “   · ú ˜À Òp ³ o u4 Ÿ x _  6 £ §5 Å q“ É r v = 5120 ± 80 m/s – Ð 8 £ ¤& ñ ÷ &% 3 Ü ¼ 9, s  ° ú כ“ É r l ” > r 8 £ ¤& ñ ° ú כ 5150 m/s ü

< 0.6 % _   © œ@ /& h  s \  ¦ ˜ Ð% i  .

Table 1. The speed of sound in solid.

Average SD Ref. Data [m/s] [%] [m/s]

Steel bar 5076 1.0 5050 [13]

PVC pipe 1564 2.3 1550 [2]

Aluminum 5120 1.6 5150 [13]

Fig. 6. The method of measuring the speed of sound in water.

3. u œ = k8 ý “ Ö ¨’ Ò × q

u  ´ê Á œ`  ¦  (0 > Ó ü t s  [ þ t # Qt  · ú §• ¸2 Ÿ ¤ > h› ¸ô  Ç  s ß ¼

¿

º > h\  ¦ Ó ü t5 Å q \  Fig. 6õ  ° ú  s  0 Au r v “ ¦ z  ´+ « >z  ´\ " f   6

 

x ~   Û ¼ ½ ™× ¼ 4 Ÿ x`  ¦ ¿ º  s ß ¼ 0 Au ô  Ç f ” ‚   © œ\  45• ¸ s

 © œ l Ö  ¦ # Œ q Û ¼1 p u y   Œ ™l • ¸2 Ÿ ¤ ô  Ç  6 £ §, } © œu – Ð = å Q`  ¦ y © œ

>  5 g" f ` O Û ¼\  ¦ µ 1 ÏÒ q tr (   .

¿

º  s ß ¼  s _   o   H 15 cm s  9, Û ¼ ½ ™× ¼ 4 Ÿ x õ    s

ß ¼  H €  • 5 cm ç ß –  `  ¦ ¿ º“ ¦ e ”  . 100   ì ø Í4 Ÿ ¤ # Œ 8 £ ¤& ñ ô

 Ç Ó ü t _  6 £ §5 Å q“ É r v = 1472 ± 23 m/s % i  . 23 m/s   H ³ ð ï

 r¼ #  – Ð" f ¨ î ç  H \  @ /K  2 % s  s  . Ó ü t5 Å q \ " f_  6 £ § 5

Å

q“ É r d ” (4)ü < ° ú   ,

v = s

γB

T

ρ (4)

#

Œl " f 㠍  H l ^ ‰ ]  t q \ P _  q Ö  ¦, B

T

  H 1 p x“ : r  Òx  ò ø Í$ í Ò

 ¦, ρ  H x 9 • ¸s  . Õ ª  X < Ó  o^ ‰_   â Ä º γ, B

^T

, ρ  “ : r • ¸ ü

< · ú š§ 4 \  _ K       H ° ú כs  .   à º[ þ t \  @ /ô  Ç \ V8 £ ¤ ° ú כ

`

 ¦   & ñ   H é ß –í  H ô  Ç s  : r s  \ O l  M :ë  H \   â + « >& h  6 £ §5 Å q“ É r d ”

(5) [13]ü < ° ú  Ü ¼ 9, “ : r • ¸ x 9  · ú š§ 4 õ  › ' a >  e ”  .

v = 1402.7 + 488t − 482t

²

+ 135t

³

+ 15.9 + 2.8t + 2.4t

²

(P

G

/100) (5)

#

Œl " f t =

100^T

s “ ¦, T  H [ O }  “ : r • ¸s  9, P

^G

  H · ú š§ 4 õ 

› '

a > ÷ &  H € ª œÜ ¼– Ð 1l · ú š\ " f 0 s  . z  ´+ « >z  ´\ " f  s ß ¼

  Œ ™|   U  ·s _  · ú š§ 4 “ É r @ /l · ú šõ  ° ú  Ü ¼Ù ¼– Ð · ú š§ 4 \  › ' a > 

 )

a † ½ ӓ É r Á ºr ½ + É Ã º e ”  .   " f “ : r • ¸ë ß –_  › ' a > d ” Ü ¼– Ð ^  ¦ Ã

º e ” “ ¦ Ó ü t _  “ : r • ¸ 20

^◦

C “    â Ä º > í ß –  ) a 6 £ §5 Å q“ É r 1482 m/s s  .

4. ”  ôX ê s X ì Ä “ Ó Þ  Ö «V R Ë

Table 2  H ô  Dz D G “ §" é ¶ @ /† < Ɠ § † < Æ ÒÒ q t 17" î `  ¦ @ / © œÜ ¼– Ð ‰ & ³



© œ & h 6   x 0 p x$ í `  ¦ › ¸ ô  Ç   õ s  . r # 3  z  ´+ « >`  ¦ l  0 A ô

 Ç  © œu   „  \  ! Ó h A ÷ &# Qe ”   H  © œ S ! \ " f q “ §l [ þ t _ 

„

 · ú š S X ‰ “   x 9  8 £ ¤& ñ `  ¦ 0 Aô  Ç [ O & ñ r ç ß –“ É r ì  r é ß –0 A– Ð, y Œ • B 

| 9

\  @ /K  10 r ì ø Í4 Ÿ ¤ z  ´+ « >\     2 ; r ç ß –• ¸ ì  r é ß –0 A– Ð, z  ´ +

«

>   õ _  ³ ðï  r¼ #  ü < / B Nd ” \  _ ô  Ç > í ß –° ú כ_   © œ@ /& h “  

s   H Ñ þ ˜ì  rÖ  ¦ – Ð ² ú š • ¸2 Ÿ ¤ % i Ü ¼ 9, z  ´+ « >  © œu \  @ /ô  Ç s

K • ¸, ’  ø @• ¸, ‰ & ³ © œ& h 6   x 0 p x$ í \  @ /ô  Ç ë  H † ½ ӓ É r o & à Ô '

‘ • ¸ 5é ß –> – Ð 6 £ x ² ú š • ¸2 Ÿ ¤ % i  .

›

¸    õ  6 £ §5 Å q`  ¦ 8 £ ¤& ñ l  0 Aô  Ç q “ §l  „  · ú š S X ‰ “   x 9  [ O

& ñ `  ¦ 0 Aô  Ç r ç ß –“ É r l ^ ‰“    â Ä º 3.0 ì  r, “ ¦^ ‰“    â Ä º 2.5 ì

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£ ¤& ñ r ç ß –“ É r l ^ ‰“    â Ä º 4.3 ì  r, “ ¦^ ‰“    â Ä º 4.2 ì  r, Ó  o

^

‰“    â Ä º 5.6 ì  r s % 3 “ ¦, z  ´+ « >   õ  y Œ • B | 9 \ " f_  ³ ðï  r

¼

#    H ¨ î ç  H \  @ / # Œ 0.8 %, 1.3 %, 2.6 % _  ¼ #  \  ¦ ˜ Ð

#

Œ z  ´+ « > r ç ß –s 
 š ¸ \  ¦ ^  ¦ M : r # 3  z  ´+ « >  © œu – Ð s 6   x

| ¨

c 0 p x$ í s  e ”  .

q

' Ÿ r ç ß – 8 £ ¤& ñ Z O Ü ¼– Ð 6 £ §5 Å q`  ¦ 8 £ ¤& ñ   H  כ s  s K  l  /

'î  r \  @ /ô  Ç 6 £ x ² ú š“ É r 4.4, ³ ðï  r¼ #  ü <  © œ@ /& h “   š ¸ – Ð Â

Ò'  8 £ ¤& ñ _  & ñ S X ‰$ í `  ¦ # QÖ ¼ & ñ • ¸– Ð Ò q ty Œ •   H \  @ /ô  Ç 6

£

x ² ú š“ É r 4.5, ×  æ “ ¦1 p x † < Ɠ §  1 l x é ß –" é ¶ \ " f r # 3  z  ´+ « >Ü ¼– Ð & h  6

 

x ½ + É _ † ¾ Ós  e ”   H \  @ /ô  Ç 6 £ x ² ú š“ É r 4.4 – Ð
 
 o &  à

Ô ' ‘ • ¸ ë  H † ½ Ó_  [ O ë  H   õ   H F N& ñ & h s % 3  .

IV. + s Ç Â ] Ø

–

Ð4 Ÿ © v à Ô\  ¦ s 6   x ô  Ç 6 £ §5 Å q8 £ ¤& ñ z  ´+ « >  © œu   H  â ] j& h s  9 ] j Œ •s  / 'î  r z  ´+ « >  © œu s  . 6 £ §   ` O Û ¼_  q ' Ÿ r ç ß –`  ¦ 8

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Table 2. The applicability to experiments using the robotstudy kit.

Preparing Measuring SD Error

Understanding Accuracy Preference time[min] time[min] [%] [%]

Air 3.0 4.3 0.8 0.6

Steel bar 2.5 4.2 1.3 0.6 4.4 4.5 4.4

Water 3.1 5.6 2.6 3.1

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[2] Earl D. Blodgett, The Physics Teacher 47, 31 (2009).

[3] Elisha Huggins, The Physics Teacher 46, 13 (2008).

[4] S. J. Jang, Mulli Kyoyuk (Phys. Teaching) 10, 69 (1992).

[5] David Potter, The Physics Teacher 41, 12 (2003).

[6] S. R. Jeon, Master thesis, Hankuk University of Foreign Studies (2002).

[7] Wilton Pereira da Silva,Jurgen W. Precker, Diogo D. P. S. e Silva and Cleiton D. P. S. e Silva, The Physics Teacher 43, 219 (2005).

[8] Richard E. Berg and Dieter R. Brill, The Physics Teacher 43, 36 (2005).

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[11] Thomas B. Greenslade, Jr., The Physics Teacher 14, 510 (1976).

[12] J. C. Lee, CodeVisionAVR C Robotstudy AT- mega8535 (Dongil Printing and Publishing Co.Ltd, Seoul, 2006), p. 30.

[13] Lawrence E. Kinsler, Austin R. Frey, Alan B.

Coppens and James V. Sanders, Fumdamentals of Acoustics (John Wiley & Sons, Inc, New York, 1999), p. 121, p. 528.

[14] B. Y. Aim, S. S. Lee and J. O. Lee, The

Korean Society of Mechanical Engineers 15, 2181

(1991).