Épisode 4

Sid is sending his toy panda Ignatz on yet another adventure! He places him on top of a skateboard, then rolls him across his patio. The skateboard comes to an abrupt stop when it bumps into a wooden bench, but Ignatz keeps moving forward, flying into the air! Sid is curious why Ignatz didn't stop moving too, so he and his friends investigate and discover that things in motion stay in motion until they are stopped-and that's inertia!