The first model is divided into two equal parts, and one part is shaded.
So, the first model shows $\frac{1}{2}$.

The second model is divided into three equal parts, and two parts are shaded.
So, the second model shows $\frac{2}{3}$.

To compare the fractions, it helps to divide the models into the same number of equal pieces. This is called finding a common denominator.

The least common denominator is the least common multiple of 2 and 3, which is 6. Divide both models into six equal parts.

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The model with more parts shaded represents the greater fraction.
So, $\frac{1}{2}<\frac{2}{3}$.