Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

What can i do to measure carbohydrates ?

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

Hi,
Sorry you weren't able to do the experiments with Daphnia. That would have been really interesting--maybe next time.

B vitamins and most others would be too difficult to measure, but you can measure vit C using iodine and starch indicator. If you are going to determine the actual concentration of vit C you will need some vit C powder to use as a standard. Don't use vit C tablets as these have fillers and you want pure vit C.

You can use a hydrometer to measure the density of the sports drinks relative to pure water but this only tells you how much dissolved solids are in the drink. To measure the sugar content, you would need to use Benedict's solution.

I don't know what else you can measure accurately. To get an actual concentration, you usually run standard solutions of known concentration along with your unknown. You take the data from running the standard solutions and graph it with the readout (what you measure) on the y-axis and the concentration (g/mL, %, moles/L, etc.) on the x-axis. Here's a video that explains how to make a standard curve in case you need help: https://www.youtube.com/watch?v=0luczWOo0rQ

Good luck!

Sybee

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

Final Important Question (For Now)- Does the benedicts solution work if the liquid is pre coloured and does it affect it ? I am not sure because the research I did showed that it is used for sugar in foods with the foods being dissolved in water and then tested. Since it is a clear liquid that is okay,... but for me all of my beverages are coloured except two - chocolate milk, orange juice and gatorade

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

I have figured out that I have to dilute the liquid if it is too concentrated
One Question:
1) Maybe I have this sort of wrong in my head but if I were to dilute the solution in water I have to make sure that the amount of beverage before dilution is the same as all the other beverages and so when I get the results from the experiment they will be accurate right ?

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

In order to compare several different solutions you need to dilute them all the same.

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

Benedict's solution is clear blue before it is used. In the presence of reducing sugars such as glucose it turns orange after heating. Testing for sugar in chocolate milk will be a problem and orange juice definitely. I'm not sure about Gatorade.

If you can do a dilution of one part drink plus two parts water (1:3 dilution) that might help to make the color change visible.

Remember that Benedict's does not react with sucrose because it is a non-reducing sugar, so if your drinks have sucrose, this test will not register it. You can convert sucrose to its component sugars--fructose and glucose--by heating it with dilute hydrochloric acid or with an enzyme called invertase, which splits sucrose into the two simpler sugars.

Also, unless you test glucose solutions of known concentration (standards), you will not be able to say how much reducing sugar is in your drinks--only that there is some, more or a lot. Comparing the resulting colors you might be able to say that one drink has more sugar than another, but it would be much better for your science project if you could say what the actual sugar concentration was.

Hope this is helpful. Let me know if you have more questions.

Sybee

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

Yes that was what I was planning to so with the HCL.

Thank You that helped me with my question for dilution.

I am sort of confused by your comment about posting on one thread, I have only posted on this one thread after you told me not to ask on other ones so I am not sure what you are referring to.

Thank You !!!!!!

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

My mistake. I thought there was a separate question when there wasn't. Sorry

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

Hello Sybee,

I have one question which i couldn't figure out the answer to online.

When I measured the conductivity of distilled water (because I needed a base) I got a negative number on my multimeter. I don't think this affects the results but one other thing I did was that since my multimeter did not have a microamps function I did the test test with just milliamps. I had assumed that it would just come to 0 regardless but now I am confused why I have a negative number.

Thank You

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

Hi,
Distilled water cannot conduct an electric current because it contains too few ions. That's why your multimeter gives a negative reading. I don't know why it does not read zero which is what i would expect--or maybe just slightly positive.

If you are curious, you could add a tiny, measured amount of sodium chloride, NaCl, to the DW and measure the conductivity again. This time it should be positive because the Na+ and Cl- ions will conduct electrons through the solution and give a reading on the meter. You could keep adding measured amounts of NaCl and measuring the conductivity. Afterwards, you could graph the data and you will have a conductivity chart. Then you could measure the conductivity of an unknown solutions and find it on the graph so that you can read off the salt concentration from a given current reading.

Sybee

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

Hello Sybee
I am really confused because I spent a lot of time researching this topic but i could't find the answer to my question.
While I was doing the electrolytes challenge I noticed that only on one side where the copper is connected to the straw and the alligator clip (which is connected to the battery clip) it changed into a black colour. The thing is that this only happened when the beverage was high in electrolytes. I am not sure what happened and I did not notice any fizzing or anything else.

Thank You

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

Do you understand now why distilled water does not carry an electric current? There's a lot of chemistry involved with electrolytes and you probably haven't had most of it in school yet.

Passing an electric current through a solution of electrolytes can result in electro-plating of a metal onto the electrodes [the copper wire in your case] and I think that's what caused the darkening of the copper.

Eventually, you should also notice bubbles of gas forming at the wires because the electric current will cause the water [H2O] to break down into hydrogen and oxygen gas, which will appear at the electrode.

I don't want you to feel confused, so please keep asking questions until you understand what is happening in the solution.

Sybee

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

Hello Sybee, Thank you for your explanation.

Yes ( I knew that distilled water did not carry an electric current because they covered that at school), I figured out why there was a negative number, it was because I had connected the wires the wrong way to the battery and so it gave a negative reading. All I had to do was switch the negative to a postitve and I had the right reading which was like you said slightly positive.

As for the electroplating, the research I did showed that it is done between to different metals. So I don't understand why copper and copper would make a difference. Also I don't understand why it does so only on one electrode.

Sorry I don't understand would really appreciate if you could explain it to me.

Thank You

SciB
Expert
Posts: 2042
Joined: Fri Feb 01, 2013 7:00 am
Occupation: Retired molecular biologist, university researcher and teacher

Re: Electrolytes - Endurance Athletes

Excellent question! You saw the flaw in the explanation. Yes, electroplating does take place between two different metals, but what I think might have happened was an electrolytic reaction in which hydroxyl ions were produced at the electrode by breakdown of some compound in the drink. The hydroxyl ions will increase the pH next to the positive electrode and this could cause a reaction with the copper wire.

The one problem with this hypothesis is that copper compounds are nearly always some shade of green or blue, not black. That's why I was thinking more of electroplating. Maybe the drink has some other metal ions like iron that could be attaching to the copper and causing it to appear dark. Which electrode does the color change at, positive or negative? Iron ions are positive, Fe3+ or Fe2+, and thus would be attracted to the negative electrode.

Here's a reference for electrolysis of a water solution: http://www1.lsbu.ac.uk/water/electrolysis.html
Here's some information on the copper compound, copper hydroxide: https://en.wikipedia.org/wiki/Copper(II)_hydroxide

As a control, you could try measuring the conductivity of a salt solution, NaCl, because this would have no iron in it. Clean off the copper, or use new wire, and attach it to the battery and see what happens. You should see bubbles of gas forming at the electrodes as the water is electrolyzed into oxygen and hydrogen, but I think the copper should not turn black.

Let me know what happens. Electroplating is a lot of fun and I used to try various metal salts and metal items to see what i could do. Copper is a good one to try because you can usually buy copper sulfate in a hardware store and use it to plate copper onto tools or other metal items.

This is kind of off the subject of your sports drink conductivity measurements, but it is good that you questioned the discoloration of the copper. Lots of things in science were picked up by accident that way.

Let me know what happens.

Sybee

Dan56789
Posts: 22
Joined: Tue Dec 11, 2018 2:50 pm
Occupation: Student

Re: Electrolytes - Endurance Athletes

Hello Sybee
When I said that the copper is black i meant like a dark brown.
The copper wire piece that I said was turning that colour was the one that is connected by a alligator clip to the negative terminal of the battery.

https://www.sciencebuddies.org/science- ... #procedure

the right side wire in the 4th picture down form above

Thank You