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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

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
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
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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