0.5 tablespoons of instant yeast is a small amount that is about the size of a cherry. When poured into a loose pile, it measures 1.6 in (4.07 cm) wide and 0.672 in (1.71 cm) tall.

In kitchen measures
1.5 teaspoons
1.5 tsp · 0.5 tbsp · 0.031 cups
about the size of a cherry
Instant yeast typically ranges 0.5–0.62 g/mL depending on how it's packed. A firmly packed scoop weighs more.