علوم الصف الخامس المنهج الجديد لغات

[mrmohab]

Unit 1 : Energy Lesson 1 : light


Light :


A form of energy that affects eye causing the sense of seeing (vision )


Difference between light energy and other forms of energy :


Lightenergy differ than other kinds of energy


Because :


It is visible energy .


Sources of light :


1. The Sun :


The main source of light on earth's surface


2. The moon :


Moon's light is a reflection of sunlight that falls on its surface .


Visible Spectrum :


Light energy which can be seen by the eye

Travel of light


v Light travels in straight lines .


Example :


The Straight line :


is The path


1.Which is taken by light rays coming from the car torch .


2.Which is taken by beam of sun rays coming from the sun and passes through a narrow hole of a window or a dark room


Activity prove that :


Light travels in straight lines


Tools : lighted candle – straight cylinder of length 50 cm


Steps :


1.Fix a lighted candle vertically


2.Put one of the 2 ends of the straight cylinder


in front of the candle flame


3.Look at the flame of the candle .


Observation :


You can see the flame


4.Bend the cylinder (not straight )


5.Try to look at the candle flame through the bent cylinder


Observation :


You can't see the flame.


Conclusion :


Light travels in straight lines

Activity prove that :


Light travels in straight lines


Tools :lighted candle – 3 cardboard screens


Steps :


1.Bring 3 pieces of cardboard , each containing a hole .


2.Put them in a row in front of a lighted candle .


Where all holes and the flame are on one straight line .


3.Look to the candle flame through the hole of the last pieces of cardboard .


Observation :


You can see the flame


4.Move any of the pieces of the cardboard to right or left


The 3 pieces are not on one straight line .


5.Try to see the candle flame through the hole of the last pieces of cardboard .


Observation :


You can't see the flame .


Conclusion :


Light travels in straight lines


Phenomena happen due to traveling the light in straight lines :


1.Formation of images through narrow holes


2.Formation of shadows


Formation of images through narrow holes :


When light travels through narrow holes :


An inverted image is formed is formed


It leads to :


Designing of photographic camera .


Activity proves that :


Light travels through narrow holes forming An inverted image :


Steps :


1.Bring a cardboard ( metallic ) box opened from on side .


2.Cover the open side by a semi-transparent paper (white balloon )


3.Make a small hole on the opposite side of the box.


In a dark room :


4.Move a lighted candle in front of the small hole


of the cardboard box Until an inverted is formed .

Observation :


An inverted image for the candle is formed


Conclusion :


Light travels through narrow holes in straight lines forming An inverted image .

v This activity is the base of idea of the camera


v This box is called pin-hole camera