L9 Diffraction & Diffraction Gratings (Unit 1 Physics BTEC Applied Science)

This Pearson BTEC Applied Science Unit 1 Physics PowerPoint covers diffraction and diffraction gratings, including wavefronts, interference patterns and light spectra.

Designed for the Waves in Communication topic, this comprehensive lesson develops students’ understanding of how waves spread when passing through gaps or around obstacles. Diffraction is defined as the spreading of waves around obstacles or through openings, with the amount of spreading depending on the wavelength and the size of the gap or obstacle.

The PowerPoint includes a starter activity with answers, key scientific terminology, detailed explanations and examples. Students investigate diffraction through gaps and around obstacles, exploring how changing the gap size or wavelength affects wave spreading. The lesson also introduces wavefronts, explaining their relationship with wavelength and the direction of wave propagation.

Students then explore diffraction gratings, learning how regularly spaced slits produce overlapping coherent waves and interference patterns. The lesson explains constructive and destructive interference, bright and dark regions, and the formation of zero-order, first-order and higher-order maxima.

Practical demonstrations using a ripple tank, laser and diffraction grating allow students to investigate diffraction and observe interference patterns. The lesson also examines monochromatic and white light, including how diffraction gratings separate white light into its component wavelengths to produce a continuous spectrum.

The resource concludes with 12 Check Your Understanding questions and answers, providing opportunities for assessment, consolidation and exam preparation.

This resource is suitable for classroom teaching, practical demonstrations, independent learning and revision for students studying Pearson BTEC Applied Science Unit 1 Physics.

File format: Editable PowerPoint (.pptx), allowing teachers to adapt the content to their teaching requirements.

Resource date: September 2026.