A set of compatible items which will enable diffraction to be investigated with slits gratings pinhole spots and other obstacles.The set comprises:1 Set of six lenses: focal lengths -100 -50 +50 +100 +200 and +1000mm3 Lens holders1 Slide holder for 50mm square slides1 Pinhole slide 50mm square with holes of 0.2 0.1 and 0.05mm1 Slide with single and double slitsSet of six slides with 1 2 3 4 5 and 6 slits respectively1 Set of three diffraction grating slides: 2 x 150 and 300 lines/mm1 Air cell for refractive index of gases. Path length 75mm approx.2 Microscope slides: 76 x 25mm1 Glass scale: 200 x 25 x 6mm scale 0 to 150 mm x 1mm1 Support stand for glass scale1 Slide 50mm square with circular obstacles for Fresnel diffraction6 Bead headed mapping pins and needle for Fresnel diffraction1 Hologram (ready prepared)1 Copy of Manual of School Laser DemonstrationsLasers can be purchased separately:B8A46139 - Philip Harris Semi-Conductor LaserB8H83651 - Unilab Solid State Laser