I did this recently with a fourth grade class as part of a "Magic Tricks with Science Day" related to the unit they were in - Light, Magnets, and Electricity (big shout out to Mrs. Lauricella who is always game to have me come in and teach her class!).
The day went something like this....
- Reviewed three things light can do when it hits an object (refract, reflect, and absorb)
- Discussed how when light refracts it can make an object appear bent in water. Students then got to pour water in a clear plastic cup and put a pencil in to observe this.
- I then told students that it can appear to bend other things as well and I did the trick above in the video. The teacher and I staged this elaborate senario where we were arguing about who was the best teacher and we decided to let the "magic arrow" decide. The kids LOVED it (we said they could try it at home with their siblings...as in who did mom like the most :)
- Students then got to draw arrows and try it themselves on each other
- After that we did the jello secret message activity (relating it to light absorption and refraction). See early post here. We used the coloring sheet from the Gems Color Analyzer Book.
It was a pretty fast paced activity filled day with the kids (which is always a good thing!)