class vi dps,north bangalore
TRANSCRIPT
CLASS VI
DPS,NORTH BANGALORE
I can reach a depth of about
80 meters in the ocean.
I am not a human being nor
a man made thing.
Who am I ?
ANS- LIGHT
Light is an electromagnetic radiation.
Light is the form of energy.
Light travels in a straight line at a speed of 2,99,792 km/sec.
Light doesn’t need any medium to travel.
It can travel in vacuum.
Light waves travel faster than sound waves.
The sunlight reaches to earth in 8min 20 sec.
The ultimate source of light is the sun.
Natural warmth of sunlight creates conducivecondition for growth & development of life.
Sunlight is key factor for photosynthesis process.
Natural light often referred as white light.
When light reaches an object, it is absorbed, reflected or passes through it.
We can see an object due to reflection of light.
Eg- sun,stars, Firefly, Fire etc.
Eg-Lamp, candle, Torch, Bulb etc.
Natural source Artificial source
The objects that produce their own light are called luminous object.
The objects that do not produce their own light are called Non- luminous object.
Luminous object Non-luminous object
The body which emits light ,when heated to a very high temperature are called Incandescent body..
Ex- Electric bulb
A Glow-worm is a
living luminous body .
It is a cold source of
light.
Q1. Which of the following is not a source of light?
a) Star b)Torch c) wood d) Lantern
Q2. Which of the following is a natural source of light?
a) Star b)Torch c) wood d) Lantern
Q3.Which of the following doesn’t produce their own light?
a) Star b)Fire fly c) Moon d) Sun
I am a non- luminous
object but still I produce
light.
Who am I?
ANS- MOON
Q1.How do we see non-luminous object?
Q2. What is the speed of light?
Q3.Give some examples of luminous object.
Q4. Why do we see light first and hear
the sound later during thunderstorm?
On the basis of passing of light-
1. TRANSPARENT OBJECT
2.TRANSLUCENT OBJECT
3.OPAQUE OBJECT
The objects which allow light to pass through it completely are called Transparent objects.
Eg- Clear glass, Air, pure water, some plastics etc.
The objects which allow light to pass through them partially are called Translucent objects.
Eg- Tracing paper, Mica, wax paper, Ground glass, Frosted glass, Butter paper, Thin sheet of plastic, Sunglasses, Thin fabric etc.
The objects which do not allow light to pass through them are called Opaque objects.
Eg- Wood, Mud ,Sand ,Brick, Metals etc.
AIM- To classify objects into transparent, translucent & opaque object by passing light through it.
MATERIALS REQUIRED- Torch, different objects.
OBSERVATION-Object/ Material View through
object(fully/ partially/not at all)
Object is opaque/transparent/Translucent)
Book
Glass(Try with any 5 objects)
Q1.A Transparent object which is mostly used in windows of houses-
a) polythene b)Glass c) wood d) None
Q2. which of the following is translucent object?
a) Cardboard b)clear glass
c) Tracing paper d) None
Q3. which of the following is not an opaque objects :
a) Wood b)clear glass
c) Metal d) sand
Q1. The object which allows light to pass through it totally is called-
Q2. Frosted glass & mist are examples of ____________
Q3. Give 2 examples of Opaque object.
If you look in water you
might see me, Yet I never
get wet. What am I ?
ANS- REFLECTION
Q1. The object which allows light to pass through it totally is called-
Q2. Frosted glass & mist are examples of ------
Q3. Give 2 examples of Opaque object.
A shadow is a dark area on a bright surface.
When an opaque object comes in the path of light then it forms a shadow.
❖1. An opaque object.
❖2. A source of light
❖3. Screen
❖4. Object must be placed in the
path of light
Size of the source of light
Size of the object
The distance between source of light & the object.
The angle at which the light is falling on an object.
A shadow shows only the outline or the shape
of the object.
Shadow does not give details of the object.
Irrespective of the colour of the object, the
shadow is always black.
In absence of screen shadow is not formed.
A small object will have small shadow where
as a large object will have large shadow.
AIM- To observe shadow of different objects & different forms.
MATERIALS REQUIRED- Torch, Objects of different size.
OBSERVATION- (Students will record observation in notebook)
Q1.Which of the following is necessary condition for shadow formation-
a) Opaque object b)light
c) Screen d) All of these
Q2.Which of these objects can cast a shadow ?
a) Butter paper b)Wooden door
c) Glass d) All
Q3. Shadow gives detail of the object.-True/False
Q1. List out 2 characteristics of shadow.
Q2. Mention necessary conditions for shadow formation.
I am a black coloured patch.When some object comes in between the way of light, then you can see me.Who am I ?
ANS- SHADOW
Q1. List out 2 characteristics of shadow.
Q2. Mention necessary conditions for shadow formation.
When the distance between the object & the source is decreased, the shadow becomes larger.
When the distance between object & screen is increased, the shadow becomes larger.
https://www.youtube.com/watch?v=yd5WRAgl1cQ
AIM- To observe size & length of the shadow formed by an object at different time.
MATERIALS REQUIRED- Chair / stick, notebook & measuring tape.
OBSERVATION- (Students will measure length of shadow & record observation in notebook)
❖ A Solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight.
❖ The dark part of the shadow is the umbra, and the part that is a little lighter is the penumbra.
A Lunar eclipse occurs when the Moon moves into the Earth’s shadow.
Ans- If the curved surface of the cylinder is placed perpendicular to the path of light , the shape of shadow becomes rectangular.
Q1. What would be colour of the shadow of a red ball?
a) Red b)Black c) Blue d) None
Q2.When will you see the shortest shadow of yourself in sunlight?
a) In Morning b) In Evening
c) At Noon d) None
Q3.During an eclipse, the sun, moon & earth are in a straight line.- T/F
Q1. What is umbra & penumbra?
Q2. When a shadow becomes smaller?
Q3. At what time in a day , you can see bigger shadow of yourself?
I help you to see things.Who am I ?
ANS- LIGHT
The property of light travelling in straight line is called Rectilinear propagation of light.
AIM- To observe path of light.
MATERIALS REQUIRED- Candle, small rubber tube/ news paper role.
OBSERVATION- ( It should be written by students)
❖The ray of light is represented by straight line
with an arrow overhead.
❖The beam of light rays are always parallel to each
other.
❖Convergent rays are the light rays from different
points tend towards single point.
❖Divergent rays are the light rays starts from one
point travel in different directions.
❖Pinhole camera is a device which works on the principle of “Rectilinear propagation of light”.
❖Light from the objects enters the camera
through the pinhole.
❖ It goes to the screen where it forms an inverted and small (diminished) image.
❖The image has the same colour as the object.
❖ If the pinhole is small, the image will be sharp and clear.
Take 2 rectangular boxes, with one box smaller than other.
In a large box, punch a small hole on one of the smaller face & cut opposite face.
Cut out both the smaller face of the smaller face.
Cover one of the open face of small box with a tracing paper.
Slide smaller box inside larger one, keeping face with the tracing paper inside.
https://www.youtube.com/watch?v=IcNEfwNeZss
Q1. Rectilinear propagation of light means-a) Light travels in a straight lineb) Light travels in a curve pathc) Light travels in a zig-zag pathd) Light travels in a Circular path
Q2. An image formed by a pinhole camera is _________and _________.a) Inverted & Real b) Only Erectc) Virtual & Erect d) Inverted &Virtual
Q1.A device which forms a photograph like image of a bright object on a screen is called_________.
Q2. The beam of light rays are always _________to each other.
Q3. What do you mean by “Rectilinear propagation of light”?
You can see nothing else when you look at my face.I will look at you in the eyes and I will never lie. What am I?
ANS- REFLECTION
Q1.A device which forms a photograph like image of a bright object on a screen is called_________.
Q2. The beam of light rays are always _________to each other.
Q3. what do you mean by “Rectilinear propagation of light”?
The bouncing off & changing direction of light on striking a plane mirror is called Reflection.
Reflection enables us to see things.
When light reflected from an object enters our eyes, we can see object.
A plane mirror reflects the light & Image of an object is formed in the mirror.
AIM- To observe reflection of light(Regular and Irregular surface)
MATERIALS REQUIRED- Torch , plain mirror, comb.
OBSERVATION-( Activity need to be performed in dark room).
Regular reflection1) It occurs when parallel
beam of incident rays remain parallel after reflection.
2) It is also called as Smooth reflection.
3) The reflected rays are reflected in one direction.
4) Image formation takes place.
5) Occurs from smooth surfaces like mirror, silver spoon , clear water etc.
Irregular reflection 1) It occurs when parallel
beam of incident light doesn’t remain parallel after reflection.
2) It is also called as Defused reflection.
3) The reflected rays are not reflected in one direction.
4) Image formation doesn’t take place.
5) Occurs from rough surfaces like wood, table, door etc.
Q1. A plain mirror forms an image of an object because it______ light from an object.
a) Absorbs b) Passes
c) Reflects d) None
Q2. Which of the following shows detail outline of an object?
a) Image b)shadow
c) Both d) None
Q3. Regular reflection occurs through rough surface. – T/F
