Iodine Clock Reaction
Reach into your kit and pull out the bag with the four bottles in it. Take everything out of the bag and place it around the white mat. Then, place the empty bag back in your box.
These liquids are color-coded for easy matching. One has green on the edges of the label and the other has blue. Start by matching the colored bottles together. The two blue bottles go together and the two green bottles go together.
First, let’s mix the green bottles together. Carefully unscrew the tops and squeeze the liquid from the smaller green bottle into the bigger green bottle. Make sure the cap goes back on tight and give it a light shake to mix.
Next, we need to mix the blue bottles together. Carefully unscrew the tops and squeeze the liquid from the smaller blue bottle into the bigger blue bottle. Make sure the white cap goes back on tight and give it a 3-second shake to mix.
Next, gently twist to open the top of the green bottle so that you can easily squeeze out the liquid. Then, fill the measuring cup with 12.5ml.
Next, let’s do the same thing with the other bottle. Gently twist to open the top of the blue bottle so that you can easily squeeze out the liquid. Then, fill the measuring cup with 12.5ml
Finally, go ahead and pour this liquid from the measuring cup into the petri dish slowly, and then watch… keep watching for something to happen.
It turned blue! And each time we do this reaction, it makes a different pattern when changing. Let’s do it again.
Pour the blue liquid from your petri dish into one of the empty cups provided and repeat the steps above to watch this reaction make a new pattern.
Now, clear your workspace and place the two empty cups in the center. Let’s see what happens when we do this same experiment in cups.
Start by filling the measuring cup all the way up with the liquid from the green bottle. Then pour all the liquid in your measuring up into the large empty cup.
Repeat the same steps with the blue bottle. Fill the measuring cup all the way up with the liquid from the blue bottle. Then pour all the liquid in your measuring cup into the last large empty cup.
Mix the liquids together by pouring one cup into the other. Do this back-and-forth three times.
Now, let’s count down from 10 to see the reaction! 10… 9… 8… 7… 6… 5… 4… 3… 2… 1… Blue! That was like magic!
Finally, let’s try it again but this time with different amounts. This time, only fill ½ of the measuring cup with the liquid from the green bottle and pour it into one of the empty cups. Tip: it should be approx. 10ml
Next, fill the entire measuring cup with the liquid from the blue bottle and pour it into the other empty cup.
After mixing three times like before, do you notice changes in the timing? This time it happened much faster!
Now let’s try it once more. This time fill the entire measuring cup with the liquid from the green bottle and pour it into an empty cup.
Then, fill only half of the measuring cup with the liquid from the blue bottle and pour it into the other empty cup.
How It Works
Two of the chemicals want to make it clear and the other two want to make it blue. They compete like a game of tug-of-war. At first, the clear team is winning, but it gets tired out and all used up, so eventually, the blue team wins. This means that the amount of chemicals we mix in can change how long the countdown takes.
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