Hang mass on the spring, read the stretch, and pin each reading to the graph. The slope of the force–extension line is the spring constant — k = F ÷ x, exactly as the classroom experiment measures it.
This reading
Weight F = m·g1.96 N
Extension x3.92 cm
k = F ÷ x50 N/m
Graph — pinned points
Slope (measured k)—
Points plotted0
Hanging mass200 g
Spring stiffness k50 N/m
Weight uses g = 9.81 m/s². Extension is x = F ÷ k, shown from the unloaded level — not the spring's full length.
Method: pick a mass, press Plot point, change the mass, plot again. Five or six pins and the slope settles on k.