Movie 8.

Labelled probe pushing different tissues in zebrafish embryos. The probe moves linearly towards a maximum distance driven by the motor (20 V, 0.1 Hz). Fish medium (1st row), animal pole at 50% epiboly (2nd row) and dorsal trunk at ∼15 somite stage (3rd row). Probe front is obscured by tissue after contact and cannot be further tracked. Tracking the trailing dye bead allows comparison of tissue resistance.