Streetlight Shadows

I love impromptu science lessons. Today's experience came from J's observations on Grandpa's shadow cast by the streetlights as we were walking to their favorite frozen yogurt store at night. Unfortunately, I didn't have my camera with me to capture the original excitement, so I tried to recreate at home under our streetlight.

We were walking down a well-lighted pathway at night, behind Grandpa. We were originally stepping on Grandpa's shadow, but as we walked, Grandpa's shadow jumped ahead of him. What caused this?

As Grandpa (modeled by J) was approaching the light, the shadow was behind him. The further away from the light he was, the longer the shadow was.

As Grandpa reached the light, his shadow became smaller and smaller and was basically straight out from his body, not at an angle.

As Grandpa walked away from the light, his shadow went in front of him and became larger (until the light from the next streetlight took over, not pictured, but imagine the series repeated).

Note: Nighttime shadows are hard to capture on camera since you don't want to use a flash. My camera had a "Handheld Night Scene" mode, which is what I used.

Luckily, the pathway was long enough to continue with our forward progression and explain what was happening to J while in real time. We definitely saw his light bulb moment.

Related Posts:

• Experiments you can do with shadows in the daylight.