14168 Experiment Pack - Additional Optics - info

STE 14168 Experiment Pack

Additional Optics

INTRODUCTION

This Experiment Pack includes an optical bench and apparatus for conducting 32 varied optical experiments, through KS4 to A level. The comprehensive Instructions and Teaching Guide illustrate each experiment and provide guidance on correct operation.

TOPICS COVERED

1.     PROPAGATION OF LIGHT

0 1.3        Light and shadow

0 1.4        Core shadow, half shadow

0 1.5        Lunar phases

0 1.6        Solar and lunar eclipse

0 1.7        Pinhole camera

0 1.8        Photometer

2.     MIRRORS

0 2.5.1      Images on a concave mirror

0 2.8.1      Images on a convex mirror

4.     LENSES

0 4.2.1      Determination of the focal length of convex lenses

0 4.4.1      Images of a convex lens

0 4.4.2      Law of imagery for convex lenses

0 4.5.1      Determination of the focal length of concave lenses

0 4.7.1      Images with a concave lens

0 4.8        Spherical lens aberrations

0 4.9        Chromatic lens aberration

5.     COLOURS

0 5.2        Colour splitting of light by means of a prism and consequent recombination

0 5.3        Additive mixing of colours

0 5.4        Subtractive mixing of colours

0 5.5        Body colours

6.     THE EYE

0 6.1.1      Model of the human eye

0 6.5        Aberrations of the eye and their corrections

7.     OPTICAL INSTRUMENTS

0 7.1        Magnifying glass

0 7.2        Slide projector

0 7.3        Microscope

0 7.4        Telescope

0 7.5        Camera

8.     WAVE OPTICS

0 8.1        Diffraction on a grating material

0 8.2        Determination of the wave length

0 8.3        Polarizing with filters

0 8.4        Rotation of the plane of polarization by inserting solid materials

0 8.5        Model of a saccharimeter

0 8.6        Photoelasticity

EXAMPLE EXPERIMENT

0 6.5     ABERRATIONS OF THE EYE AND THEIR CORRECTIONS

(n.b. all worksheets have relevant setup diagrams)

Material:

1 Optical bench or

2 Stand rails and 1 rail bond

1 Experimental lamp

1 Rod 10 cm

1 Lens in mount f = +100 mm

1 Lens in mount f = +300 mm

1 Lens in holder f = -100 mm

1 Set of single circle slits

1 L-slit

2 Lens and slide holders

1 Slide holder detachable

1 Screen, white

2 Connecting leads

Electric power supply

The correction of aberrations of the eye by means of spectacles is to be explained. Convex lenses as well as concave lenses are used as „spectacles“. This experiment can also be carried out with real spectacles.

Preparation: Arrangement according to the illustration. The experimental lamp with the mounted L-slit is  put ont he left end of the optical bench by means of the sliding saddle. The lens (f = +100 mm) is attached as eye lens at a distance of about 40 cm from the L-slit by means of lens holder and sliding saddle. The single circle slit (d = 8 mm) is put in the slide holder and attached to the lens. The single circle slit represents the pupil. The lens with the single circle slit is turned in such a way that the single circle slit faces the source of light.

The screen is put on the optical bench at a distance of about 11 cm form the lens by means of the sliding saddle for scales. The screen represents the retina. The lens is moved in such a way that the object (L-slit) is clearly pictured.

1.     Experiment: Short sightedness (eyeball is too long):

The distance of the screen to the lens is enlarged by about 5 cm. The image is obscure. The clearness of the image can be corrected by a concave lens (f = -100 mm) at a distance of about 16 cm in front of the lens. The concave lens represents the spectacles.

2.     Experiment: Far-sightedness (eyeball is too short):

The distance between the screen and the lens is reduced by about 2 cm. The convex lens                   (f = +300 mm) which is mounted at a distance of about 13 cm in front of the eye lens makes a clear image possible again. Spectacles for correcting far-sightedness contain convex lenses.

Conclusion: Short-sightedness can be caused by a too long eyeball. Concave lenses are used for correction. Far-sightedness can be caused by a too short eyeball. Convex lenses are used for correction.