I'd hypothesize that that's a different effect. Orange juice is denser than water, so if you pour water into orange juice, a lot of it will float on top. If you

I'd hypothesize that that's a different effect. Orange juice is denser than water, so if you pour water into orange juice, a lot of it will float on top. If you pour orange juice into water, on the other hand, the orange juice will sink through the water, mixing relatively evenly. By the same reasoning, tea should actually mix better if you add the tea first, since milk has about the same density as orange juice and tea has about the same density as water. But in the case of tea and milk, you just have to bite the bullet and stir it manually if you want to avoid scalding.