If you've been paying attention to the summer Olympics currently being held in Rio de Janeiro, Brazil, you know there has been some recent hoopla over the water in two swimming pools turning green. We have an answer now as to what caused it!

According to a Time article published a few days ago, "a contractor poured hydrogen peroxide into the diving well and the large pool in the center last week. The chemical reacted with the chlorine and turned the water an emerald green and increasingly murky." 

As you may already know, chlorine is added to water to kill germs, but adding hydrogen peroxide offsets what chlorine does. Mixing the two apparently caused the color change and murkiness of the two pools. So now we know!

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