To sign sunrise, take your non-dominant hand and hold it down flat in front of you, so that your non-dominant forearm represents the horizon. Then take your dominant forearm, lay it in front of the other arm so that they are parallel and side by side, and form the ASL letter C sign with your dominant hand. Then slowly raise your 'C' hand by pivoting from the elbow, representing the sun slowly rising on the horizon.
Teach your toddler the sunrise sign when they start asking you about how or why day shifts into night, and vice versa. If you have the chance to go on a camping trip with the whole family, teaching your toddler the sunrise sign while actually witnessing the real deal would be a most memorable experience.
Teach this sign along with the other flash cards pertaining to nature and times of day.