and now we're going to combine that with a teaspoon a teaspoon of ayuday
thermal kinetics the speed at which reactions happen that's what we're playing with today here
on tcore and we're playing with iodine clocks i am excited about this experiment because
it's not something i've done before and i think it's going to be really unique so we're going to
try two different versions along with a couple mini experiments we're going to do one that
comes from a science kit and we're going to do one that you can do at home from stuff that's
underneath your sink or in your kitchen cabinets before we get into these experiments we need to
talk about what's happening in this iodine clock reaction it's really unique these clock reactions
usually involve a series of different chemicals and basically we're going to mix them back and
forth and as these chemicals mix once a chemical is completely used up it turns a color so this all
has to do with reaction times and how the process is happening so to make this happen we're going to
be using for our at-home version some hydrogen peroxide vitamin c tablets some pearl starch
any kind of starch really then you're going to use some of this iodine and a set of plastic cups so
to run this iodine clock experiment and to test out the time the reactions are happening
we're going to do a series of three experiments so we're going to do the experiment where we're
going to have 1 000 milligrams and we're going to crush it up and we're going to put
it in two ounces of water solution then we're going to take 500 which is lower so i believe
the reaction should happen faster and then we're going to try 2 000 and we're going to
test all those times and see how we can get the best reaction out of our homemade ingredients
all right so now that we have our vitamin c and our different cups we have to put cups in front
of those and now we're going to make our solution a so we're going to take one teaspoon of vitamin c
and now we're going to combine that with a teaspoon of iodine oh that's really cool so
this is color and when it goes into the 1000 the iodine is completely absorbed by the vitamin c
but in the 500 milligrams it's not oh the 2000 completely absorbs it look at it
that's awesome so our 500 is not clear our 1000 is and our 2000 is so now we are going to add two
more ounces of water and we're going to label that solution a still colorless and here's our 2000
still colorless now remember the 1000 is our control in this experiment so that is what we are
basing all of our conclusions off of which is why we have one that is colorless as well and one that
is colored for solution a we have one teaspoon of vitamin c one teaspoon of iodine and then we have
two ounces of water and that's what makes up our solution a so this one has 2 000 of the vitamin c
this has 1 000 of the vitamin c and this has 500 milligrams of the vitamin c so for our solution b
you're going to use two ounces of water three tablespoons of hydrogen peroxide and half a
tablespoon of liquid starch we're gonna make that three different times in our disposable cups and
now we're going to make some liquid starch and now we're going to very gently stir now we're going to
add half a teaspoon of liquidy starch water sweet all right there you have it three solution b's
okay before we do these reactions over here and test out our results i wanted to test something
that hasn't been done before a potato is a whole starch and so i was really curious if we could
take a potato and make the iodine clock reaction happen on a potato so we don't even need solution
b we're just going to use solution a actually take that back there's one thing we need from solution
b and that's a hydrogen peroxide and it's going to play a critical part in this reaction later
so let's go ahead and get our potato chopped up and if you like potatoes as much as i do
we talked about a potato on the podcast so you can watch it on two core dug the potato sweet
okay so we have three slices of our potato here we're going to test one that's going to have
solution a on it just solution a so we're going to combine solution a with our starch
that is the potato okay before we add the solution a onto our potato i'm going to go
ahead and chop it up so we can release some of those starch juices and water i'm going to
go ahead and add the rest of the solution a to this potato and it looks clear because it has
1000 milligrams on it okay so there's our potato nothing over here is happening and it shouldn't
happen because there's nothing to separate the bond between the vitamin c and the iodine so over
here we just have starch and iodine combining together if i take the iodine i drop it on this
piece of paper towel you get this orange color now if i take iodine and i combine it with a starch
you get this really cool black color almost instantaneously and it does not happen over
here on the paper towel now to make this reaction happen something has to separate the bond here
between the vitamin c and the iodine so to make that happen we have to use hydrogen peroxide
what this hydrogen peroxide is going to do is it's going to combine with the vitamin c stripping
the iodine away from the vitamin c and then that vitamin c is then going to react with the starch
so this reaction does take time so we're going to take it we're going to put it on this paper
towel and that's what makes this reaction so special is that it is a iodine clock it does not
happen instantaneously it has to be assisted to a certain degree all right so let's use
some hydrogen peroxide here so we see the hydrogen peroxide reacting it's turning white in our cracks
which means it is reacting with the vitamin c which is really promising and good and now we
start to see some black and in those cracks is where the iodine is basically reacting with the
starch in the potato itself and this makes science so cool and exciting because this is so cool
so now we can see that because we introduce the hydrogen peroxide it basically takes this reaction
and destroys it and tears it apart and that's how you get the color and if i introduce more starch
by stabbing the potato the reaction just continues to escalate and so i'm going to scrape this away
and you're left with a starch that's reacted with iodine and given us this
really awesome color change so now that we've done that and we've tested out our theory here
let's go ahead and see how our reactions are going to do with the 500 our control the 1000
and our solution a the 2000 so you're going to take solution a and you're
going to pour it into b and then you're going to pour it back and forth ready go
this was just really slow
and each time you pour it it gets darker and darker
okay so our iodine clock solution took way longer look it keeps getting darker and darker and darker
as the reaction time goes on so our reaction took way longer this took like three minutes
um which i don't know if it's because they were sitting out or whatnot but that took a while
so let's go ahead and try the 500 milligram one um i think this one will be much faster because
you can already see that the iodine is here i think as soon as we pour this one it'll react
there it is there was no clock because there was not enough
vitamin c to hold on to all of the iodine ions so basically as soon as it hit this it reacted
because there were free iodine molecules that were able to grab the starches that were in here
so that's pretty cool okay let's try this one this one i feel like is going to take a minute
and the one thing that i found so when i was doing solution a i poured in extra hydrogen peroxide to
speed up the reaction because i was worried i didn't have enough um so what's really cool is
that you can add more hydrogen peroxide and the reaction will happen faster or the less hydrogen
peroxide you have the reaction will happen slower so this one is going to take forever because
it has the most vitamin c and it has 2 000 milligrams and i did not up the hydrogen
peroxide amount so this reaction might not ever happen so to make it happen we're going
to add in even more hydrogen peroxide just to help it out and get it going
so we have slowed the reaction time down significantly in this one
by not having enough hydrogen peroxide to strip away and having way too much vitamin c
what i really like about the potato demonstration is it's a oh did you see it happen in my hand
it's so cool that it just instantly changes the color like it literally just goes like blue all
of a sudden and then slowly turns its darker shade but what i love about the potato reaction
is that it's something that you can have in your house and all you need is a potato
and some iodine and some hydrogen peroxide and vitamin c so you don't even have to have
the liquid starch if you don't have it because i mean we all got potatoes laying around right
there it is this one took way longer and had to have some help from the extra hydrogen peroxide
but there it is so yeah the 1000 and gives you the best amount of time the 500 reacts way too
quickly like we talked about before because the iodine is present with the starch and so it reacts
instantaneously because you don't have the vitamin c and hydrogen peroxide reaction to happen first
and then with the thousand it also happened a little slower i would have added maybe a
little bit more hydrogen peroxide just to assist in the speeding up of the reaction
this was great and our potatoes worked really well so i am super stoked oh it's white now okay
so i poured in 3 500 milligrams of vitamin c and if i pour it in it reverses it so then if
i take the hydrogen peroxide can i like redo it that should be how it works right we'll
give this guy a minute to do its thing okay let's try this one see if we can reverse it
gone reversed it's like all right on clock experiments never happened
okay so our kit is all unpacked and it is from carolina.com we're just gonna do one experiment
out of this book there's like four or five different iodine clock experiments that you can do
this book has really cool catalyst in it and we're going to experiment with one of them but it is
copper sulfate so this guy is going to be critical in our reaction time all right so we're going to
use 10 milliliters of ki now we're adding sodium disulfate we're adding 10 milliliters of this
so this is an actual real iodine clock reaction that we are putting it together currently
so we have sodium theosulfate and we have potassium iodine currently in these two
containers all right now we're going to add three milliliters of hcl so that is hydrochloric acid
three milliliters and then we are going to add in our starch so we're gonna use five milliliters and
now in these two cups we're going to put hydrogen peroxide and now for one of them we're going
to add two milliliters of this copper sulfate so we're gonna add it to our b cup right here
all right we're gonna swirl these now we're going to pour them into here and now we're
gonna see which one reacts faster remember this one has our catalyst this one does not
oh there it is look at that beautiful blue color instead of that green color that we were getting
that looks awesome and all that catalyst did was increase the activation energy of our reaction
to give us this really deep beautiful blue color i love it how blue and deep that is
oh it's just like magic man it just like you see it go and it goes and then it turns um so this
one over here took about 14 seconds this one over here took about 23 and so it's really really cool
because at the end you still get the same reaction you still get the same components you still get
the same color so the copper sulfate just really helped boost this reaction and you know there's
a bunch of other really cool reactions that you can do in this book but i must say i appreciate
that home version i think that home version is fantastic and it's a great way to get your
hands on things that you can do at home but in a laboratory setting there's nothing better than a
true set of equations and reactions and chemicals that really break down to give you the true
components of an equation guys if there's anything else you guys want to see us do with iodine clocks
or any other science experiments on the channel let us know in the comments below or check out
one of these other videos that's on the side over here we'll see you guys in the next one