Generation Kiichiro Kagawa NPO: Fukui Science Education Academy - - PowerPoint PPT Presentation

Physics Education for Young Generation

Kiichiro Kagawa

NPO: Fukui Science Education Academy

JAPAN

The Aim of our NPO (FSEA)

• 1) Science workshop for young people
• 2) Development of new experiment
• 3) Cooperation with foreign countries

Retired from Fukui Univ. in 2010, while NPO was founded in 2009

CD分光器をつくっているところ 水を入れるとコインが浮かび上がってくる （竹ぐしは目の位置の基準にする）

Regular private class for children (2009~2014), two times in a month, Sat. ９：３０～１２：００

児童が自分の考えを述べている

大気圧の実験（留学生が指導）

Our hope is to bring up excellent scientists and engineers

The most representative educational experiment we developed

Frictionless equip. Artificial snow crystal Water lens microscope

PATENT:

• No. 5257879

All these were published In J. Phys. Education (England)

Attitude towards Physics Education

（１）Try to Separate from school textbooks （２）Try to use ordinary materials. Don’t use commercial kits, which degrade children’s ability. （３）Try to encourage to have logical thinking through experiments （４）Try to use beautiful phenomena as the topics

• f study (rainbow, snow crystal so on)

（５）Try to encourage to repeat the experiment with careful observation (small discovery) Even physics education, there should be originality.

• Frictionless Demonstration Using Fine

Plastic Beads for Teaching Mechanics Chapter １ Frictionless Demonstration Using Fine Plastic Spherical Beads for Teaching Mechanics

Introduction

• Mechanics is most important to understand Physics system
• However, only through training to solve calculation problem in high

school Most unpopular subject in high school

The reason 1) Due to the friction, we cannot demonstrate the law itself. 2) For falling objects, phenomena finish in a short time (less than 0.5 second). Student cannot see carefully with enough understanding

Commercial equipments for frictionless motion

Air slide track ¥210.000 (2000 US$) Car (1set): ¥21.000 Car including slope ¥46.000

1㎜

Plastic beads

Uniform linear motion Diameter is about ０．３ｍｍ

Work as ball bearing; beads are rotating Microscopic view

• f Plastic beads

Almost no energy loss because the mass is very small

Demonstration of the principle of this frictionless equipment for children

The plate with doll move smoothly, The Ping-Pong balls are rotating.

Rainbow Experiment Using Fine Plastic Beads

Beads scattered on a black paper work, same as water droplet.

How to treat the beads

Take out the breads after experiment using vacuum cleaner,

• r wipe with wet paper

Scatter like shaking pepper . Almost invisible for our eye. But if you look at the surface from an oblique, it looks slightly white.

Book of Nuffield “O” level(1972), using metal small ball(1~2mm)

Heavy object: ~1kg Only horizontal surface, No application for slope iron ball bearing

Published in Journal of Physics Education

2008

・Easily obtainable object of which bottom is flat (but should be light) ・Very cheap( 80 US$ for 1 bottle (700g),

• ne time only a few g)

・Even slope, the beads can be attached by electrostatic force. (frictionless slope) ・Systematic understanding is made because all experiments are done using the same object on the frictionless plate. .Students can touch the equipment by themselves as they like.

Ａｄｖａｎｔａｇｅｓ ｏｆ Ｂｅａｄｓ Method

Weak points: 1) In high humidity, friction increases 2) Too much density increases friction

Objects used for frictionless demonstration

lid petridish Bottom plane should be flat and less 100g

90 x 60 x2 cm, 7kg For group experiment (ordered to professional)

Equipments for frictionless demonstration

Size: 183 x 91 x 6 cm Weight: 7.5 kg (Using Styrofoam, but covered by 2mm Plastic plate) Flatness is important We say, “friction plate”, “ beads plate”

First Law of motion

(Uniform linear motion, viewed from the top)

Strobe lighting; T=0.25s

Pulse light source to record the track

Diode light source(red or green) ; Off and on , Periodically flash Petri dish Recorded using a digital camera: 1sec Repetition :5 Hz

Plastic lid with a hole

pin

Circular Motion Using a String and Cylindrical pipe

If there is quite no friction, the circular motion keeps going on like a planet motion. string Using projected shadow, We can show that circular motion is Simple harmonic

• scillation

Projected shadow Bright light source

Rotation of rigid body

Usually, to have the image is difficult for students

Center ter of

• f mass

ss Center ter of

• f mass

ss

On the frictionless plate

Law of conservation of angular momentum( L = r x p )

Circular motion using string End of string was fixed so as to be coiled around the pole; ( with decreasing r , V increase )

Law of inertia

Uniform motion Weight moves to frontward

It stay there;

no transmission of force

Pull suddenly Suspended weight

F=ma(運動の第二法則) High school textbook Using Wheel car

For students, it is difficult to understand that this is a general low

Weight:２０ｇ On bead plate

M

Accelerated motion

Constant force

Ｍ＝53. 53.４ｇ Ｍ＝153. 153.４ｇ

LED, 10 Hz

pulsar

Petri dish

V = △X/ X/ △T

Demonstration of second law

Ｆ＝ｍａ 50 100 150 200 250 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 時間ｔ [秒] 平均の速度ｖ [ｃｍ/ｓ]

(48.8g) (98.8g) (148.8g) (248.8g)

F=ma

(Second Law of Motion) We can change m and F, independently.

F: weight(２０ｇ) ビーズ板 M Under various mass

Acceleration

Constant force

The relati tion

• nsh

ship p between en time and velocit ity

Action and Reaction Law (Third law of motion)

On the frictionless table High school textbook

N S N S N S S N S N S N S N

Repulsion force each other, without touching

Small Neodymium magnet are arranged In a circular form

図8-2

Circular magnet

改良型 小型ネオジム磁石

Demonstration using circular magnet, under strobe flash light

Action and reaction, using jumping frog

Usually, difficult to see the force itself

Demonstration on practice problem

On the smooth surface C, there is an object D (M kg) on the smooth slope B, of which angle is Θ. Another 0bject A (m kg) is placed on the slope

• quietly. Then, the object C slide down on the slope because of no friction

between the surfaces. Questions: 1) What is the acceleration of A against C ( in X, Y component) 2) What is the relative acceleration of A against D 3) What is the relative acceleration of D against C

We can demonstrate using the frictionless plate and frictionless slope.

Ｍｇ

Free falling object Falling object on a slope

Ｆ＝Ｍｇ a= a=ｇ Ｆ＝Ｍｇsinθ a=ｇsinθ(small)

Mgsinθ Mｇ Mg Mg cosθ

Acceleration become small by using slope, when Θ＝１°acceleration =(１/６０)g

We can see the phenomena as slow motion, easy to understand.

Frictionless slope

Can measure the force to the slope direction

Inclining fricti tionless ta table Smooth th slope

Free-fall on the smooth slope

Regardless of the mass, falling is the same We can see in slow motion

Uniform acceleration motion on the inclined beads plate

Angle of slope ：0.8 time：~3.5 sec acceleration：0.13m/s2 Measurement can be made using a stopwatch (very instructive)

The relation of distance and time 0.00 0.20 0.40 0.60 0.80 1.00 1.20 0.00 1.00 2.00 3.00 4.00 Time(s) Distance(m)

The relation of velocity and time 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.0 1.0 2.0 3.0 4.0 Time（ｓ） Velocity（m/s）

Time vs. length Time vs. velocity

Monkey Hunting

Commercial equip. ¥39,000

Vertical direction motion is the same between the monkey and the stone

ｘ方向と、ｙ方向の運動は独立。 サルも弾もｙ方向に対しては 同じ落下運動をする。

Experiment of monkey hunting using the inclined beads plate

One --Two--Start

Regardless of the speed The stone can attack The monkey

10

Stone is shot aiming the monkey

ⅹ

y

monkey stone

Both Monkey and stone, the motion of the Y direction is the same . The Motion takes place slowly

What angle gives the most far distance? (under the same initial speed)

ⅹ

y

1 2 sin cos 2 tan , cos 2 tan sin 2 1 cos

max 2 2 2 2

                            x g v x x v gx x y t v gt y t v x

g v  2 sin

2



45  

(ｇ`＝ｇsinθ)

` `

Many Application of Frictionless Plate

Horizontal spring vibration

Model for diatomic molecule

Concept of 3 kinds motion: Vibrational, Rotational, Translational

Non-gravity (Weightlessness) demo.

In a elevator, which freely fall. During the falling on the frictionless slope(~20o) , no expansion of the spring beads beads

Collision

Completely exchange Small one is repelled

Momentum conservation for inclined collision

× × ○ ○

Before collision After collision

Composed momentum vector is conserved

Conversion from potential energy to kinetic energy （beads are attached by electrostatics force ）

v

ｈ

Beads plate Plastic sheet with fine beads

1 1 2 2 1 2 2 1

2 2 1 2 1 2 1 2 1 gh v mgh mv mv mgh mv mgh mv mgh

• 

      

エネルギーの変換 0.5 1 1.5 2 2.5 3 3.5 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 ｈ[ｍ] ｖ[ｍ/ｓ] エネルギー変換 y = 18.774x y = 19.605x 1 2 3 4 5 6 7 8 9 10 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 ｈ[ｍ] ｖ２[ｍ/ｓ]２

theory

Velocity vs. height

measurement

Speed meter

Plastic sheet Petri dish ball

Comparison of falling speed between ball and petri dish

Ball is late: (energy is consumed for rotating the ball, thus kinetic energy of motion is reduced )

Smooth slope

Elastic and Inelastic collision

Bound slowly （no movement of small plastic balls） Collide with hard wall, plastic balls move randomly

Stop Energy change to thermal energy Cushion

High sensitive detection of magnetic force

Beans plate The bar magnet direct to North

Application of Frictionless Plate For Wave Demonstration

Wave propagate very fast, thus it is very difficult to observe。 We made slowly propagating waves using the frictionless table.

Fine beads

Plas asti tic lid (diam amete ter 5cm) i is c connecte ted using a t a thin rubber s str tring f for wav ave p propag agat ation.

Slowly-moving wave

Frictionless Plate Chain of thin plastic lid.

Reflection of wave at fixed edge

Reflection of wave at free edge

Standing wave

Superimpose of Waves(+ ,+ )

Textbook

Wave machine

Superimpose of Waves(+,+)

Superimpose of Waves(+,-)

International seminar in Fukui

10 students (Syiah Kuala Univ. , Faculty of Science) came to Fukui to attend international seminar under the support of Japan Monbushou (2008).

Before demonstration After demonstration

慣性の法則

6 4

慣性の法則

10

作用・反作用の法則

10

F=ma 3 7 F=ma

1 9

作用・反作用の法則

5 4 1

Questionnaire survey from university students

Understand A little understand

Inertial law Inertial law Action and reaction Action and reaction

don’t understand

• Frictionless Demonstration Using Fine

Plastic Beads for Teaching Mechanics Chapter 2 Short Presentation Using Movie 1) Frictionless exp. 2) Soap bubbles exp. 3) Air gun exp. (workshop for children including mentally disable children)

From a small workshop in Fukui (Aug. 8, 2017)

END Thank you very much for your attention