The Development of the New Experimental Devices to Accept �the Principle of the Force and Motion�� �Author Nobuyuki KAWAI� �Kobe Municipal Ibukidai Lower Secondary School , ��JAPAN
Presentation contents
1 Background and Problem
3 Experiment class and Finding
The starting section�� Background and Problem
Question 1: Which force was bigger, forward or reverse,
when the car ran at a constant velocity?
A : Forward force / B : Reverse force
① A＜B
② A＝B
③ A＞B
A
B
The law of inertia
Question 1:
Which force was bigger, forward or reverse, when the car ran
at a constant velocity?
A : Forward force / B : Reverse force
① A＜B
② A＝B
③ A＞B
A
B
A > B 70 %
students’ answers
The law of Inertia
Question 1:
Which force was bigger forward or reverse when the car ran
at constant velocity?
A : Forward force / B : Reverse force
① A＜B
② A＝B
③ A＞B
A
B
A > B 70 %
It is necessary the force for the object to run at a constant velocity.
⇩ students’ ideas
The law of inertia
Question 2:
If you continue pulling the cart, how does the speed of the cart change? Provided that there is not any friction between the cart and the floor.
① It runs with the constant speed all the time.
② It runs fast in the beginning,
It runs in the constant speed immediately.
③ It becomes faster.
The principle of force and acceleration
Question 2:
If you continue pulling the cart, how does the speed of the cart change? Provided that there is not any friction between the cart and the floor.
① It runs with the constant speed all the time.
② It runs fast in the beginning,
It runs in the constant speed immediately.
correct ③ It becomes faster.
83 %
65 %
18 %
17 %
The principle of force and acceleration
Question 2:
If you continue pulling the cart, how does the speed of the cart change? Provided that there is not any friction between the cart and the floor.
① It runs with the constant speed all the time.
② It runs fast in the beginning,
It runs in the constant speed immediately.
③ It becomes faster.
The principle of force and acceleration
83 %
The car keep running at a constant velocity even if the force is continued applying.
students’ ideas
⇩
⇩
The 2nd section � �Purpose and Experimental device
The mechanism
Weight
Speedometer (BeeSPIν)
Weight
Silk Gut
Object (label)
Pulley
Pulley
The Experimental Device
| Initial Velocity ＝ ０ | Initial Velocity ≠ ０ |
Resultant Force＝0 | | |
Resultant Force≠0 | | |
Table 1: The principle of balance of forces ( Kawakatsu 1992 )
| Initial Velocity ＝ ０ | Experimental device |
Resultant Force＝0 | Resultant Force＝０ ⇔ Do not begin to move
a Law of Inertia in the initial velocity=0 | |
Resultant Force≠0 | | |
Table 1: The initial velocity and the resultant force
| Initial Velocity ＝ ０ | Experimental device |
Resultant Force＝0 | Resultant Force＝０ ⇔ Do not begin to move
a Law of Inertia in the initial velocity=0 | |
Resultant Force≠0 | | |
Object
15ｇ
15ｇ
Stand still
Table 1: The initial velocity and the resultant force
| Initial Velocity ＝ ０ | IExperimental device |
Resultant Force＝0 | Resultant Force＝０ ⇔ Do not begin to move
a Law of Inertia in the initial velocity=0 | |
Resultant Force≠0 | Resultant Force≠0 ⇔ Begin to move
a Law of Motion in the initial velocity=0 | |
Object
15ｇ
15ｇ
Stand still
Table 1: The initial velocity and the resultant force
| Initial Velocity ＝ ０ | Experimental device |
Resultant Force＝0 | Resultant Force＝０ ⇔ Do not begin to move
a Law of Inertia in the initial velocity=0 | |
Resultant Force≠0 | Resultant Force≠0 ⇔ Begin to move
a Law of Motion in the initial velocity=0 | |
Object
15ｇ
15ｇ
Stand still
⇒
Begin to move
Object
Table 1: The initial velocity and the resultant force
| Initial Velocity ≠ ０ | Experimental device |
Resultant Force＝0 |
Resultant Force＝0 ⇔ Does not accelerate/decelerate
a Law of Inertia |
|
|
|
|
Table 2: The initial velocity and the resultant force
| Initial Velocity ≠ ０ | Experimental device |
Resultant Force＝0 |
Resultant Force＝0 ⇔ Does not accelerate/decelerate
a Law of Inertia |
|
|
|
|
Object
15ｇ
15ｇ
Same velocity
Table 2: The initial velocity and the resultant force
| Initial Velocity ≠ ０ | Experimental device |
Resultant Force＝0 |
Resultant Force＝0 ⇔ Does not accelerate/decelerate
a Law of Inertia |
|
Resultant Force≠0 |
Resultant Force≠0 ⇔ Accelerate /Decelerate
a Law of Motion
|
|
Object
15ｇ
15ｇ
same velocity
Table 2: The initial velocity and the resultant force
| Initial Velocity ≠ ０ | Experimental device |
Resultant Force＝0 |
Resultant Force＝0 ⇔ Does not accelerate/decelerate
a Law of Inertia |
|
Resultant Force≠0 |
Resultant Force≠0 ⇔ Accelerate /Decelerate
a Law of Motion
|
|
Object
15ｇ
15ｇ
same velocity
15ｇ
10ｇ
acceleration
15ｇ
10ｇ
deceleration
Table 2: The initial velocity and the resultant force
| Initial Velocity ＝ ０ | Initial Velocity ≠ ０ |
Resultant Force＝0 | |
|
Resultant Force≠0 | |
|
15ｇ
15ｇ
same velocity
15ｇ
10ｇ
acceleration
15ｇ
10ｇ
deceleration
15ｇ
15ｇ
stand still
⇒
begin to move
Table 3: The initial velocity and the resultant force
The 3 rd. section��Experiment class and Findings
No. 1 The object stands still. When the weight of both ends is same,
Which is bigger the left force or right one?
( left force , the same , right force )
The object ( stands still , runs either left or right ).
The Worksheet to the prediction of results
object
Pulley
Weight
(both ends)
1st The prediction of result
3rd The discussion
2nd The experiment
The experiment class in session (2020)
Table 4: The correct answers to Q. 1 and Q. 2
after studying a Force and Motion
% correct % correct
Control Group Experimental Group
n=32 n=22
Question 1 28.1 72.7 **
Question 2 25.0 86.4 **
**p＜.01
The final section��Conclusion
力と運動の実験Ⅱ（鉛直方向）
100.0ｇ
ペットボトル
水
電子天秤
エレベータの中
椅子
実験中の様子
実験後の討論
意見を出し合う(実験前)
Thank you for your attention
Nobuyuki KAWAI
Kobe Municipal Ibukidai J.H.S
The mechanism
The 3 rd. section��Experiment class and Findings
| 運動状態 | 電子天秤の値 | 合力の向き |
1階 | 停止 | 100.0 | はたらいていない |
上昇中 | 加速中 | 100.0から増加した後,減少 に転じて100.0に近づく | 上向き |
等速度 | 100.0 | はたらいていない | |
減速中 | 100.0から減少した後,増加 に転じて100.0に近づく | 下向き | |
４階 | 停止 | 100.0 | はたらいていない |
初速 | ν＝０ | ν≠０ |
合力＝０ | 静力学， 力の原理Ⅰ 合力＝０ ⇔ 動き出さない 初速度０における慣性の法則 | 動力学 合力＝０ ⇔ 加速(減速)しない 慣性の法則 |
合力≠０ | 動力学， 力の原理Ⅱ 合力≠０ ⇔ 動き出す 初速度０における運動の法則 | 動力学 合力≠０ ⇔ 加速(減速)する 運動の法則 |
形成する 概念 | 力の概念は初速度０における 力の原理で形成する | 力と運動の概念は力の概念を もとに発展させる |
合力＝０ ⇔ 動き出さない
初速度０における慣性の法則
上昇するボール①に はたらく力の向き | 実験後 | 計 | |||
↑上向き | ↓下向き | その他 | |||
実験前 | ↑上向き | 3(17) | 8(44) | 3(17) | 14(78) |
力ははたらかない | 1(5) | 0(0) | 0(0) | 1(5) | |
↓下向き | 0(0) | 3(0) | 0(0) | 3(17) | |
計 | 4(22) | 11(61) | 3(17) | 18(100) | |
①
コインの投げ上げ
J.Clement.(1982).Students’ preconceptions in introductory mechanics
MIF*的素朴概念
実験Ⅱ実施前後の生徒の回答
* MIF: Motion Implies a Force
（兵庫県内公立中学2年生18名 調査2020年）
単位：人（ ）は％
| 物体は静止している ν＝０ | 物体を持って左に動かす ν≠０ |
合力＝０
| 静力学,力の原理Ⅰ (ｱ)Ａ＝Ｂ， 静止したまま 初速度０における慣性の法則 | 動力学 (ｲ)Ａ＝Ｂ， 速さは一定 ３個の速度計がほぼ同じ値を示す 慣性の法則(等速度運動) |
合力≠０
| 動力学,力の原理Ⅱ (ｳ)Ａ＞Ｂ，左に動き出す 初速度０における運動の法則 | 動力学 (ｴ)Ａ＞Ｂ, 加速する 速度計の値がだんだん大きくなる (ｵ)Ａ＜Ｂ, 減速する 速度計の値がだんだん小さくなる 運動の法則 |
実験Ⅰ 鉛直方向
・「力と運動」の概念を理解できていない教員
「成果と課題」
今後の取り組み
・教員への調査数を増やし，詳細に検討する。
・教員研修の在り方と指導法を考案し，実施して検証する。
➡ （子どもに対して） 誤った考え方を定着，誤った考え方への支援のおそれ
理科教員の予想
・子どもの解答で最も多かった選択肢を予想できていない教員
➡ 子どもの考えを把握できなければ，
子どもがどのように学んでいるかを捉えることはできない
ご静聴ありがとうございました
神戸市立塩屋中学校
河 合 信 之
この研究は2019年度兵庫教育大学共同研究費の助成を受けています。
The 3 rd. section��Experiment class and Findings
Table 1: The answer to Q.1 and Q.2(Kawai2021)
Question 1 ② ② ● ●
Question 2 ③ ● ③ ●
% student 12 18 5 65
○: correct, ●: wrong, n=57
| Initial Velocity ＝ ０ | Initial Velocity ≠ ０ |
Resultant Force＝0 | Statics Resultant Force＝０ ⇔ Do not begin to move Inertial Law in the initial velocity=0 | Dynamics Resultant Force＝0 ⇔Do not accelerate/Decelerate Inertial Law |
Resultant Force≠0 | Dynamics Resultant Force≠0 ⇔ Begin to move Law of Motion in the initial velocity=0 | Dynamics Resultant Force≠0 ⇔Accelerate /Decelerate Law of Motion |
Conception to form | Conception of the Force is formed by the principles of a Force in the initial velocity=0. | Law of Force and Motion based on the conception of the Force. |
Table 2: The balance of a force ( Kawakatsu 1992 )