STRAND 3.0 FORCE AND ENERGY.pptx

1. STRAND 3.0 FORCE
AND ENERGY
3.1 Light

2. LIGHT
•How does light travel

3. MOVEMENT OF LIGHT THROUGH MATERIALS
• Transparent Materials:
• Transparent materials allow light to pass through them easily without scattering the
light rays. Examples include clear glass, water, and air.
• When light passes through a transparent material, it travels in a straight line,
maintaining its direction and intensity.
• Translucent Materials:
• Translucent materials allow some light to pass through, but they scatter the light rays in
different directions. Examples include frosted glass, wax paper, and thin fabrics.
• Light passing through translucent materials may be diffused or weakened, making
objects on the other side less distinct.
• Opaque Materials:
• Opaque materials do not allow light to pass through them. Examples include wood,
metal, and thick plastics.
• When light encounters an opaque material, it is absorbed or reflected by the surface,
preventing it from passing through to the other side

4. ACTIVITY
• Draw ray diagrams of images formed on plane mirrors

5. • The First Law of Reflection:
• This law says that when light rays hit a smooth surface, like a mirror, they bounce off in a
predictable way.
• The angle at which the light hits the surface is equal to the angle at which it bounces off.
• Imagine throwing a ball at a wall. If you throw the ball at a certain angle, it bounces off
the wall at the same angle.
The Second Law of Reflection:
• This law says that the incident ray, the reflected ray, and the normal (a line perpendicular
to the surface) all lie on the same plane.
• In simpler terms, this means that the incoming light ray, the reflected light ray, and an
imaginary line perpendicular to the surface all line up in a flat plane.
perform an experiment to show reflection of light on plane mirrors (laws of reflection)

7. FORMATION OF SHADOWS AND ECLIPSES IN NATURE
Formation of Shadows:
• Shadows are formed when an object blocks light from a source,
creating an area of darkness behind it.
• When light from a source, such as the Sun or a lamp, encounters
an opaque object, the object blocks some or all of the light rays.
• The region behind the object where light is blocked is called the
shadow.
• Shadows have different characteristics depending on the size,
shape, and distance of the object from the light sour

8. FORMATION OF SHADOWS

9. FORMATION OF ECLIPSES IN NATURE
Solar Eclipses:
• A solar eclipse happens when the Moon passes between the
Earth and the Sun, blocking the Sun's light.
• Imagine you're standing on Earth, looking up at the sky.
Normally, the Sun shines brightly during the day.
• During a solar eclipse, the Moon moves in front of the Sun,
blocking its light and casting a shadow on a small part of the
Earth.
• If you're in the shadow's path during a total solar eclipse, it might
get dark for a few minutes, almost like night during the day!

10. SOLAR ECLIPSES

11. LUNAR ECLIPSES:
• A lunar eclipse occurs when the Earth comes between the Sun
and the Moon, blocking the Sun's light from reaching the Moon.
• Picture yourself on the Moon, looking back at the Earth.
Normally, you see the Sun shining on the Moon, making it bright.
• During a lunar eclipse, the Earth moves between the Sun and the
Moon, casting its shadow on the Moon.
• When this happens, the Moon may appear to turn a reddish
color. This is because some sunlight passes through Earth's
atmosphere and bends toward the Moon, giving it a reddish
glow.

12. LUNAR ECLIPSES

13. ACTIVITY
•carry out activities to demonstrate and illustrate the
formation of shadows and eclipses (solar & lunar
eclipses)

14. FORMATION OF RAINBOW IN NATURE
Sunlight and Raindrops:
• Rainbows form when sunlight shines through raindrops in the air.
• Sunlight is made up of many colors that we can't see separately. These colors are like
the colors of a rainbow.
• When sunlight passes through a raindrop, it bends, or refracts, and separates into
different colors, just like when you shine light through a prism and see a rainbow.
Refraction and Reflection:
• As sunlight enters the raindrop, it bends, or refracts, because the raindrop acts like a
tiny prism.
• Once inside the raindrop, the light reflects off the back surface of the raindrop and then
exits the raindrop.
• This reflection causes the light to bend again as it leaves the raindrop, creating a
spectrum of colors.

15. IMAGE FORMATION IN PLANE MIRRORS
Reflection in Plane Mirrors:
• A plane mirror is a flat, smooth surface that reflects light rays.
• When light rays hit a plane mirror, they bounce off in a predictable way, following the laws
of reflection.
Formation of Images:
• When you stand in front of a plane mirror and look at your reflection, you see an image of
yourself.
• This image appears to be behind the mirror, even though there's no actual object behind
it.
• The image in a plane mirror is called a virtual image because it's formed by the apparent
intersection of light rays that are reflected by the mirror.

16. ACTIVITY
•use digital or print media to search for information on the
movement of light through materials, image formation on
plane mirrors, the formation of shadows, eclipses and
rainbow in nature,
•discuss the applications different media (mirrors, periscope,
kaleidoscope, lenses, magnifying glass, hand lens, mirage,
rainbow of movement of light through

17. •Project: Learner uses locally available
resources to make a functional periscope

18. In periscopes

19. A PERISCOPE
•A periscope is an apparatus is used to see places that are out
of sight such as over walls, fences or around corners
•Periscopes are also used in submarines.
•Submarines are ships that move underwater
•People in submarines use a periscope to see what is above
water
•In vehicles
• In road construction

20. LEVERS AS SIMPLE MACHINES
•How are levers used in our everyday life

21. •Class 1 Lever:
•Examples:
• Seesaws: The fulcrum is in the middle, and the load (person) sits
on one side while the effort (another person) pushes down on
the other side.
• Pliers: The fulcrum is at one end, the effort is applied at the
other end, and the load (object being gripped) is between them.
• Scissors: The pivot point is where the two blades are joined, with
the effort applied at the handles and the load (material being
cut) between the blades.

22. ACTIVITY
• Name parts of class 1 leavers used in day to day life
• Describe parts of the class 1 levers as used in making work easier,

23. •Class 2 Lever:
•Examples:
•Wheelbarrows: The wheel acts as the fulcrum, the effort
is applied at the handles, and the load (e.g., dirt, rocks) is
placed between the wheel and the handles.
•Nutcrackers: The nut acts as the fulcrum, the effort is
applied at one end, and the load (nut) is placed between
the pivot point and the effort.

24. ACTIVITY
• Name parts of class 2 leavers used in day to day life
• Describe parts of the class 2 levers as used in making work easier,

25. •Class 3 Lever:
•Examples:
• Fishing rods: The fulcrum is at the handle, the effort is applied
at the tip of the rod, and the load (fish) is caught at the other
end.
• Tweezers: The fulcrum is at one end, the effort is applied at the
other end, and the load (e.g., small object, hair) is grasped
between the tips.

26. ACTIVITY
• Carry out activities in groups to demonstrate the use of
common levers as simple machines, (a hole punch, pliers,
scissors, a see-saw, wheelbarrow, bottle openers, nail
clippers, a nutcracker, shovel, fishing rod, kitchen tongs and
tweezers.)
•use digital or print media to search for information on how
levers make work easier in day to day life

27. •Project: In groups make and use a beam
balance from locally available materials

28. SLOPES AS SIMPLE MACHINES
•How are slopes used in everyday life?

29. SLOPES AS SIMPLE MACHINES
In pairs discuss the meaning of slope as a simple machine (inclined plane)
types of slopes used as simple machines include:
• Ramps:
• Ramps are sloping surfaces that connect two different heights.
• They are used to move objects or people from a lower level to a higher level with less force.
• Examples include wheelchair ramps, loading ramps for trucks, and ramps in parking garages.
• Slides:
• Slides are sloping surfaces typically found on playgrounds.
• They allow children to slide down from a higher platform to a lower one in a fun and safe way.
• Slides are often made of smooth, slippery materials like plastic or metal

30. • practical examples on where slopes are used to make work easier around the
school environment (ladders, ramps, staircase, road winding up-hill, wedge,
roofs, loading a lorry),

31. HOW SLOPES ARE USED TO MAKE WORK EASIER IN DAY TO
DAY LIFE,
• Wheelchair Ramps: Sloped pathways are crucial for accessibility, allowing
individuals using wheelchairs or other mobility aids to navigate buildings and
public spaces easily.
• Roads and Highways: Roads are often constructed with gradual slopes to
facilitate smoother transportation of vehicles
• Gardening and Landscaping: In landscaping, slopes are strategically used to
control erosion, improve drainage, and create visually appealing terraced
gardens.
• Construction: Slopes are employed in construction for various purposes,
such as grading land for building foundations, creating drainage systems, and
ensuring stability in structures like retaining walls.

32. EXTENDED ACTIVITY
•use digital media to search for information on how
slopes make work easier (elevators/lifts,
escalators/moving stares, staircase, ladders,
cableways, ramps, road

33. •Project: make a simple slope for use in
school or at home using locally available
materials

34. ASSESSMENT
•Demonstrate the movement of light through materials
•Illustrate the formation of shadows and eclipses in
nature
•Identify common levers used in day to day life
•Demonstrate the use of levers to make work easier
•Identify types of slopes used as simple machines