1. • An introduction
to light for my
fourth grade
science
students by Mrs.
McColgan

2. What Is Light?
What is visible light
How do light
and what are some
of its sources? waves act?

3. What is visible light and
what are some of its sources?
• Visible light is a
form of energy,
that can be seen.
• Sources are the
sun, stars, electric
lights, fire…

4. How does
light
act?
Light moves Light can move
Light moves in a straight line through
in waves. away empty space.
from its source.

5. How does light act?
• Light moves in waves.
• Different colors of light have different
wavelengths.
• Other forms of energy have waves, but
they can’t be seen.

6. • VISIBLE SPECTRUM= Light energy that can be seen
• White light can be broken into the colors of the rainbow.
• R ed, O range, Y ellow, G reen, B lue, I ndigo, V iolet
• ROY G BIV helps us remember the colors of the visible spectrum
from longest to shortest wavelength.

7. Measuring Wavelengths

8. Light moves in straight lines
away from its source.
• Light does not
go around
corners
• Therefore, we
cannot see
around corners.

9. How Does
Light Help Us See
Objects?
• Light travels to an object and then travels
from the object to our eyes.
• In order for us to see an object there needs
to be a straight path of light from the
object to our eyes.

10. Review
• What is light?
• What are its sources?
• How does light travel?
• How are light waves measured?
• What is the visible spectrum?
• What are the colors of white
light?

11. What Happens When Light
Hits Objects??

12. What Happens When
Light Hits an Object??
• That depends on the material
the object is made of.

13. What happens when
light hits an object?
• Some objects reflect,
or bounce light back

14. When light hits smooth,
shiny surfaces….
• It reflects off at the
same angle it hits
them, like a ball
bouncing off a wall.
• So.. we see a clear
image in a flat mirror,
or other smooth, shiny
surface.

15. When light hits
smooth, shiny
surfaces…
• The surface
reflects more light
than it absorbs.
• Therefore, we see
a clear image.

16. What happens when
light hits other
surfaces?

17. Opaque Materials
• Don’t allow light to pass through
• Cannot see through opaque materials
• Objects behind them cannot be seen
• Name some opaque materials.

18. What happens when light
hits opaque objects?

19. What happens when
light hits black or
white objects?
• Black objects
absorb light, and
don’t reflect any
colors of light.
• White objects
reflect all the
colors of the
spectrum.

20. What Happens When
Light Hits Transparent
or Translucent Objects?
• Some materials transmit light, or
allow light to pass through them, and
us to see through them as well
• Trans– a prefix meaning through,
over, or across

21. Transparent Materials
• Allow light to pass
through so
whatever is behind
can be seen clearly
• Name some
examples of
transparent
materials

22. Translucent Materials
• Allow light to pass through, but
scatter it so that whatever is behind
them can be seen, but not clearly
• What are some materials that
scatter light, and blur the image??

23. Seeing the Color of
Transparent
or Translucent Objects
• Transparent or translucent objects
are the color of the light they
transmit, or let through.
• They absorb all of the other colors.
• Blue glass lets blue light pass
through it.

24. What Happens When
Light Moves from One
Material to Another?
• Light bends
when it moves
from one
material to
another
• This is called
refraction

25. Just as you slow
down when you run
into water, light
slows down.
•

26. Refraction
• The water bends
the light, so the
fork appears to
be in a different
place.

27. What Happens When
Light Hits a Lens?
• When light hits a lens, a transparent object
with a curved surface, it bends the light.
• Depending on the lens, objects can be
made to appear larger or smaller.

28. Concave Lenses
• Concave lenses
are thinner in
the middle, and
make the object
look smaller.

29. Convex Lenses
• Convex lenses
are thicker in
the middle and
make objects
appear larger.

30. Special thanks to…
•Phil Collins, Dance into the Light
Dedicated to
• www.google.com/images my 4th
grade
•Madonna, Ray of Light
science
students.