| Behaviours that observationally look very similar have different meanings for different children. |
| Any two consecutive cards will be observationally indistinguishable in color. |
| Of this group, the Cepheid variables have been studied in greatest detail, both theoretically and observationally. |
| I don't feel particularly suited for it, my mind doesn't work that observationally. |
| Those results are observationally equivalent to a non-linear hysteresis that appears only at low levels of combined inflation and labour productivity growth. |
| This result confirms observationally for the first time previous theoretical results, by a team of Geneva, about the effect of metallicity on stellar rotation. |
