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 This  kinesthetic-  activity is designed to help students visualize complex time dependence of the Spin 1/2 system.
 
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 In pairs, students use their arms to represent the different time dependencies of eigenstates and superposition states of the Spin 1/2 system.
 
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 The whole class discussion focuses on how different states vary with time.
 
This activity provides a concrete and physical way of representing spin-1/2 states which have complex coefficients. By providing a geometric representation of states at particular times as well as time evolved states, students may begin to understand the importance of relative phases in quantum mechanics.