Transcript Year 9 - Mrs Lilley Science

Year 9
The light of my life.
• Lesson 1; What is light?
Brain teaser.
• What is at the beginning of eternity, the
end of time and space, the beginning of
every end, and the end of every place?
What is light?
• Light is also called radiant energy.
• Light is composed of photons, which are
small pieces of energy.
How does light travel?
• Light travels in straight lines, in a wave
pattern.
Model; slinky
Electromagnetic spectrum
Handout
The electromagnetic spectrum.
• The EMS is a way of showing all of the
different energy waves in the universe.
• They range from very short wavelengths,
such as gamma rays (b), to very long
wavelengths such as radio waves (a).
Gamma rays
• The shortest wavelength ray, thus it has
the highest energy.
• Gamma rays are made when isotopes
break down, releasing energy.
• Can be used to kill cancer cells in some
people.
X rays
• The next longest wave.
• X rays are also high energy, they can pass
through skin and muscle, but are stopped
by bone.
• This is why they are used to look at
peoples bones!
UV rays.
• Ultra-violet rays are the next longest ray.
• They are made in the Sun and travel to
Earth.
• Most are reflected back into space by the
ozone layer, but some travel to Earth’s
surface.
• They cause sunburn, which is why we
should…
Visible light.
• The part of the EMS we can detect.
• It is made of 7 different coloured
wavelengths;
• Red, Orange, Yellow, Green, Blue, Indigo
& Violet.
• Violet has the shortest ʎ and red the
longest ʎ.
IR rays.
• Infra-red rays are longer than visible light,
we can’t see IR but some animals can.
• IR is also called ‘heat waves’ and can be
detected using a thermal camera (or a
speed camera!)
Microwaves.
• Microwaves get water excited! It causes
the molecules to vibrate more and more
quickly and thus heat up.
• That’s how a microwave oven works; it
gets the food to cook itself!
Radio waves.
• Long waves, up to 100km long!
• When received by an antenna, they are
converted to sound.
What can we see?
• We can only see a very small part of the
EMS, the visible light section (400 - 700λ).
• Some insects can see ultraviolet (UV) light
and cats use infrared (IR) to see in the
dark.
• Lesson 2; light and dark.
Luminosity.
• Luminous objects give off their own light;
the Sun, lamps etc.
• Non luminous objects bounce light off their
surfaces, but don’t make their own light;
mirrors, the Moon etc.
Shadows.
• A shadow is formed when a solid object
blocks light rays.
Shadows
3
12 noon
2
1
Mid
afternoon
Mid
morning
4
Sunrise
Sunset
5
1
3
5
Sundials.
Modern
Aztec
• A sundial is a device that measures time
by the position of the Sun. In common
designs such as the horizontal sundial, the
sun casts a shadow from its style (a thin
rod or a sharp, straight edge) onto a flat
surface marked with lines indicating the
hours of the day.
• As the sun moves across the sky, the
shadow-edge lines up with different hourlines on the plate.
Summary; use the words to fill in
the gaps.
Distance lamp medium shadow source straight vacuum
• A desk _______ gives out light.
• Something that gives out light is called a _______ of
light.
• Light travels in _______ lines.
• Light does not need a ______ to travel through.
• Light from the Sun travels through the _____ of space
to reach us.
• A light year is the ______ light travels in one year.
• When an object blocks light there is a
_____________.
• A desk lamp gives out light.
• Something that gives out light is called a
source of light.
• Light travels in straight lines.
• Light does not need a medium to travel
through.
• Light from the Sun travels through the
vacuum of space to reach us.
• A light year is the distance light travels in
one year.
• When an object blocks light there is a
shadow.
• Lesson 3; Reflectors and non reflectors.
Reflector or non reflector?
• Why do some surfaces reflect and others
not?
• Collect a sample from the tray.
• Set up the light boxes and see what will
reflect and what will not.
• What do the reflectors have in common?
• What about the non-reflectors?
Reflectors are…
• Smooth
• Pale in colour
• Shiny
Non reflectors are…
• Rough
• Dark in colour
• Dull
Transparent, translucent or
opaque?
• Transparent: completely see through.
Glad wrap.
• Translucent: somewhat see through.
Wax paper.
• Opaque: not see through.
Tin foil, you 
Law of reflection.
Law of reflection.
• The angle of incidence is always equal to
the angle of reflection
Key
I= incident ray
R= reflected ray
N= normal line
Øi = angle of
incidence
Ør = angle of
reflection
• Lesson 4; drawing ray diagrams.
Drawing ray diagrams
1. Draw the outline of ray box and mirror.
2. Draw a dot where the light leaves the ray
box, another dot further along the light ray,
and join the two using a ruler.
3. Draw a normal where the light ray hits the
mirror surface with a ruler.
4. Put a dot where the light ray leaves the
mirror and another further along the ray.
Connect the dots with a ruled line.
5. Label lines/apparatus and draw arrows
showing the direction of the light.
Light Box
Mirror
Activity
•
1.
2.
3.
4.
5.
Complete a ray diagram for;
Plane mirror (measure angles)
Deeply convex mirror
Shallow convex mirror
Deeply concave mirror
Shallow concave mirror
Plane mirror
Shallow convex mirror
Deeply convex mirror
Shallow concave mirror
Deeply concave mirror
• Lesson 5; fun with mirrors.
Making shapes with light.
Mirror drawing
• Fold a piece of paper in half and rule a line
down the middle.
• Draw a simple picture on one side of the
line, place the mirror along the line.
Now..
• Draw the other half of the picture, using
the mirror.
• Have a go with the mirror maze as well.
Up periscope.
• Lesson 6; Lasers.
Alarm
clock
Safe
Laser burglar alarm
• Use the handout to complete the alarm
task.
• Lesson 7; Laws of refraction.
Law of refraction
• When light enters an optically denser
medium it slows down and bends towards
the normal.
Activity
•
1.
2.
3.
4.
Complete a ray diagram for;
Oblong block
Triangle block
Convex lens block
Half circle block
‘Magic’ tricks
• Pencil and beaker.
• Coins and beaker.
• Prism.
• KW 714
• How do we see?
The eye.
http://www.kscience.co.uk/animations/eye_drag.htm
How do we see?
• Incoming light must pass through the
cornea and pupil.
• The lens then focussing the light on to the
retina.
• The retina then sends electrical signals to
the brain, telling you what can see.
Video.
• Let’s watch the Discovery Channel video
on sight!
Make the model eye.
• Make the model eye, glue it into your
notes and label the parts.
• Follow the colour code.
• Don’t forget the clear layers.
• Colour the iris in the same colour as your
own eye.
• Lesson 9; the pinhole camera.
The pinhole camera.
• Follow the instruction to make a ‘pringles’
pinhole camera.
Neat!
The image is upside down!
• The image transferred to your retina is
upside down and must be flipped by your
brain.
Today;
• Lesson 10; eye dissection.
Eye dissection
• Follow me as we complete the eye
dissection.
• Remember this came from a living animal,
so respect the materials provided for you.
Lenses.
• Concave
• Convex
• Diverging lens
• Converging lens
The lens
• The light enters the
eye and is focussed
on the retina.
• Set your ray box with
a convex lens.
• Draw a ray diagram
showing the focal
point.
Optical illusions.
• Take a look at the optical illusion cards,
• What’s happening?
• Your eye tricks your brain!
•
http://www.youtube.com/watch?v=SvNjsOl1Ag0
Today;
• Lessons 11 13 project work.
Today;
• Lesson 14; The colour of light.
The colour of light.
• Set up a prism inside the rainbow box and
observe the light which leaves the prism.
White light is actually…
• Made up of
• Red
• Orange
• Yellow
• Green
• Blue
• Indigo
• Violet
ROYGBIV
It’s about waves!
• Each colour has a different wave length,
when they combine they create white light.
Newton’s colour wheel.
•
•
•
•
•
•
•
•
Make a colour wheel.
900 Red
450 Orange
450 Yellow
450 Green
450 Blue
450 Indigo
450 Violet
• Primary colour lights.
Primary colour lights.
Magenta
Yellow
White
Cyan
Activity
• Read Pg 65, in Science book Y9.
• Copy the notes about primary colour
lights.
• Then answer Q5 on Pg 67.
Reflection of colour.
Blue
Green
Filters.
• Through a red filter; red colours look
brighter, light colours look pink and all
other colours look dark.
• Through a blue filter; blue colours look
brighter, light colours look blue and all
other colours look black.
• Through a green filter; green colours look
brighter, light colours look green and all
other colours look black.
Colour blindness
• Lesson 16; revision.
• Complete the revision sheet, then play the
millionaire game.
Today;
• Lesson 17; Final test today.