minor rewording

src/lecture_5.md

@@ -107,7 +107,7 @@ If a crystal is symmetric under $90^\circ$ rotations, then $(100)$, $(010)$ and
     After this lecture you will be able to:
 
     - Define the reciprocal space, and explain its relevance
-    - Construct a reciprocal lattice from a given lattice
+    - Construct a reciprocal lattice from a given real space lattice
     - Compute the intensity of X-ray diffraction of a given crystal
 
 ### Reciprocal lattice