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Natural sciences

Grade 8

Energy: electricity, heat and light

Module 11

Reflection and refraction of light

  • LIGHT is another common type of energy.
  • You parents or educators would like to have "eyes at the back of their heads" or would like you to believe that they see everything. We know that this is impossible, though, and for a simple reason.

Activity:

To determine the terms and concepts that relate to light

[lo 2.1, lo 2.3, lo 2.4]

Light travels along a straight line.

Light can change direction, though, and this happens in two ways:

  • Refraction
  • Reflection

REFLECTION: We are going to look at reflection as it occurs with mirrors.

When a beam of light arrives at a certain angle, it will be reflected at the same angle.

ANGLE OF INCIDENCE = ANGLE OF REFLECTION

Activity:

To establish concepts relating to reflection [lo 2.4]

Assignment 1:

1. Draw a sketch of a mirror, showing the angle of incidence and the angle of reflection. Use a protractor.

Assessment of the Sketch

Has the sketch been drawn correctly?

[LO 2.4]

Curved mirrors

Curved mirrors have many applications. They enlarge or diminish and distort the image. A curved mirror can be CONCAVE. This will CONVERGE light beams towards a fixed point, the FOCUS.

Other mirrors may be CONVEX . They will cause light beams to DIVERGE (spread apart). This scales down the image. An application of this is evident in the rear view mirror of a motor car or in wing mirrors.

The same effect can be achieved with polished metals.

Assignment 2:

1. Try the following:

Polish the surface of a large serving spoon to get it to shine.

Look at your own image in the concave and on the convex side of the spoon and compare the shape of the reflections.

Draw the differences in the spaces that are provided:

Concave Convex

Draw convergent and divergent beams from the right to add to the following sketches. Get your educator to help you.

Assessment of Sketches

Were you able to complete the sketches correctly?

[LO 2.4]

Assessment

LO 2: Constructing Science Knowledge:

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

This is evident when the learner:

  • recalls meaningful information;
  • interprets information;

2.4 applies knowledge.

Memorandum

Assignment 1:

LIGHT

  • LIGHT is another common type of energy.
  • You parents or teachers would like to have "eyes at the back of their heads" or would like you to believe that they see everything. We know that this is impossible, though, and for a simple reason
  • Light travels along a straight line. Light can change direction, though. This can be achieved in two ways:

REFLECTION:

  • We see this happening in the case of mirrors.

When a beam of light arrives at a certain angle, it will be reflected at the same angle.

Angle of incidence = angle of reflection

CURVED MIRRORS

  • Curved mirrors have many applications.
  • They enlarge and distort images.
  • A mirror could be C ONCAVE
  • It will CONVERGE light beams towards a fixed point, the FOCUS.
  • Other mirrors may be CONVEX .
  • They will cause light beams to DIVERGE (spread apart)
  • This scales down the image.
  • An application of this is evident in the rear view mirror of a motor car or in winged mirrors.

  • Try the following:
  • Polish the surface of a large serving spoon to get it to shine.
  • Look at your own image in the concave and in the convex side of the spoon and compare the effect of the shape on the reflections.

Draw the differences in the spaces that are provided:

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Natural sciences grade 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11050/1.1
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