Last Wednesday, April 3, was National Find a Rainbow Day, and children’s librarian Amanda Hairston gave her Science Club kids a lesson on light and refraction to help celebrate it.
She started her lesson off with an explanation of how rainbows are formed.
“You have to have rain,” she said, “and when the sun comes out and hits the water, it refracts into the droplet and comes back out, separated into all the different colors of the rainbow.”
She then drew a diagram on her white board showing the refraction process as she defined refraction, saying it is the change in the direction of the light wave, caused by a change in the wave’s speed.
The diagram showed the light wave splitting and changing direction as it hit a droplet of water, helping the nine gathered children’s understanding of the process.
Hairston also explained that, “White light is visible light,” and gave them the classic ROYGBIV acronym to help them remember the different colors of the rainbow, or “All the visible colors of light,” and explained a little about light that is not visible to the naked eye, such as infrared and ultraviolet light.
There was one more small experiment before the afternoon’s hands-on activity.
Hairston took a clear glass container of water and had children look through it at a card with two arrows pointing in different directions. Looking at the arrows through the glass, the arrows appeared to be pointing one way; when they looked at the card again without the glass, they noticed that the arrows had switched places. The experiment again demonstrated refraction.
After the lesson on light, it was time for the children to begin the afternoon’s activity, making a magnifying glass out of only a few simple materials: a small yogurt container, plastic wrap, a rubber band, and some small beads.
“Light travels really fast, but it has to slow down,” Hairston said. “We’re going to use that to make our magnifying glass.”
She showed them one that she had already assembled, drawing attention to the fact that she had let the plastic wrap that covered the container sag a bit in the middle.
She added water to the top of the plastic wrap —“That’s what will create out lens,” Hairston told them — and when the children looked through that makeshift lens, the beads that Hairston had placed at the bottom of the cup looked larger.
Then the children got to construct their own magnifiers.
They placed one or two small beads at the bottom of their yogurt cups, then placed a piece of plastic wrap loosely over the cup.
“It’s got to curve to magnify,” Hairston reminded them. “The bigger the dip, the bigger the magnification.”
The plastic wrap was secured by the rubber band, and a small bit of water was poured into the dip in the plastic wrap, creating the lens and which created the magnification.
“Wow! The little butterfly looks really big now!” exclaimed 8-year-old Sarah Martin as she looked through her lens.
“This was really cool, and my science kids are too smart to just talk about rainbows,” Hairston said at the end of the session. “This was fun.”