Science Buddies: "Ask an Expert"

For my science fair project I really would like to work with thermochromic objects and why they change color in certain temperatures. I am having a hard time coming up with a solid testable question and am looking for some advice.

Hi Soccerstar910

Welcome to Science Buddies! I apologize for the delay in responding to your inquiry.

This is a fascinating topic for a science fair project.

You have an original idea for a project and you know that you need to develop this into an experiment with measurable results. You do have two parameters that are measurable, color and temperature, so all you need is an experiment. Here are some suggestions.

You can develop a new application for thermochromic dyes. I saw some products mentioned (baby bottles and rubber ducks), where avoiding a high temperature is important. Can you think of a unique application that you can test? You will need a dye that changes color at the appropriate temperature. Is there any use for a thermochromic soccer ball or accessory?

Here's an idea for a medium that could be used for testing thermochromic dyes:

http://leftbraincraftbrain.com/2015/04/ ... ing-slime/

Here's a website that shows thermochromic wallpaper, glass, and film. This site also lists suppliers for thermochromic materials.

http://openmaterials.org/materials-101-thermochromic/

Here's a brief report on thermochromic transition metal compounds. Perhaps you could do a basic study on the behavior of a specific thermochromic metal complex. Notice the two students here used a UV visible spectrum to monitor color change, and they show the change in the electron orbitals that corresponds to color change. The synthesis of the compounds is described and there is probably enough information here for you to try to reproduce the study and expand on it. This would be a basic research project.

http://www3.amherst.edu/~thoughts/conte ... omism.html

Here's an abstract for a journal article describing the chemistry of a thermochromic compound, 4-pyridinophenolate. Unfortunately you would have to find a library that has this journal to see all of the details, but you can get an idea of what was done by reading the abstract. The structure of the molecule is included here also.

http://pubs.rsc.org/en/content/articlel ... ivAbstract

Here's another abstract describing an experiment on the thermochromic properties of crystal violet lactone. It might be worthwhile to ask your teacher if there is a copy of this recent article of Journal of Chemical Education available so you can see the details.

http://pubs.acs.org/doi/abs/10.1021/ed400578q

Does this give you any ideas that you would be interested in developing? All you need is one question to answer for your science project. Please let us know what idea you might be interested in pursuing and we can provide additional suggestions.

Donna Hardy

Thank you so much for replying. Your information was a big help! I have come up with a few Ideas:
1. I am interested in trying to apply a thermochromic dye to the bottom of soccer cleats as they get very hot when I play on artificial turf.
2. I have been playing around with these thermochromic spoons I have at my house and have noticed that they change color in cold temperatures. This is unusual because most thermochromic materials change color when heat is applied. I could compare the spoons to for say the slim.
3. Is there something that can be applied to a material to make them change in hot and cold temperatures?

Hi,

I like all of your topics; any could work for a science project.

The soccer shot application is especially relevant, but you would need pigments that work in the range of about 100 to 200 degrees F (37 to 93 degrees C). Here is a recent news article about the problem with artificial turf soccer fields.

https://www.washingtonpost.com/news/ear ... -kick-off/

Thermochromic spoons could have an application also, to check to see if microwaved soup is hot enough or too hot, for example. And these would be useful for testing pigments. You need to know if the pigments are toxic, however, you decide to develop an application that is used for direct human contact. I am not familiar with the availability of thermochromic spoons, but if you have one, then someone has already done this and it would not be a unique project.

Here is a company that offers thermochromic pigments; you will have to check on the temperature range available. Click on the contact us tab to find the e-mail address and phone number. Get all of the information you can the company; check out the technical data sheets to get all of the information available before you contact the company.

You need a pigment that has the right temperature range and that is in a format that will stick to the bottom of a soccer shoe. And you might be able to request free samples for your project, but you need to know exactly what you would be doing before you inquire about this possibility.

http://www.qcrsolutions.com/Site/Home__ ... _Corp.html

Also, you should check with your teacher to make sure this project meets the requirements for your science fair. Developing a thermochromic soccer shoe is more of an engineering project and some science fairs require projects that are experiments. So look at the science fair categories and decide where you can enter this project. Comparing results of two or more pigments and a control would meet the requirements for an experiment, so you could easily do an experiment if you needed to. Or you could spend more effort in developing the product if it's for an engineering project.

Do you have access to a lab with a scanning spectrophotometer? It will be easy to measure temperature, but you need a method for measuring color also. Matching color chips and taking a photograph might work, but you need to explore the possibilities.

Donna

The science fair does require an experiment. Is there a way I could turn the cleat idea into one? Also, I don't have accesss to a scanning spectrophotometer Is it possible to do an experiment involving thermochromism without one?

Hi Soccerstar910,

This project is definitely suitable for an experimental format also; you just need to invent the product and do the experiment. You will need an independent variable and a result that you can measure with a purpose for doing it.

Perhaps you could compare different formats for applying the color to the soccer shoes and measure which one works the best in terms of providing a visible indicator for color and providing durability.

Or perhaps you could use one material to apply the color and compare the use of different thermochromic dyes, or maybe compare using one dye a mixture of dyes. Think of something that would be useful to know about the design of a thermochromic soccer shoe.

What are you going to use for the bottom of a soccer shoe? Do you have access to a collection of identical soccer shoes that you could use? Or, can you get a sheet of soccer shoe sole material to cut into pieces to use? The soccer shoe material is one of your controlled parameters, so should be the same for every sample and control. Plan to run each sample in duplicate or triplicate.

If you don't have a scanning spectrophotometer, look for a cell phone app that could be used, or practice taking photographs that clearly show the color changes. Perhaps you could find paint chips from the paint section of a hardware store to match the colors. You need something to establish the color standard.

Does this help?

Donna

I have lots of pairs of old cleats that all have a plastic bottom that I will use for the experiment. What if I tested two different thermochromic dyes with different reaction temperatures to see which one is more effective?

What temperature range are you looking at? Have you found a thermochromic dye or dyes that changes color at about the right temperature? Do you know what you will use to mix with the dye to apply it to the shoes? The medium could be the independent variable. Or, do you want to use different dyes, or a combination of dyes?

Do a little more research of the thermochromic dyes are available for you to use and that will help you decide what to use. You want an experiment with just one independent variable, and ideally you will want to test 4-5 variable conditions, keeping all other parameters constant. You want to have a question that you can answer with your experiment,.

It would be a good experiment if you could find 4-5 different dyes to test, or at least 3. Or use one dye and test different concentrations of the dye.

Donna

I have found three different types of pigments:
1. changes at 86 degrees F or above
2. changes at 72 degrees of below (it is cold activated)
3. changes at 65 degrees F or above
I was thinking of mixing each one with lacquer and I found the appropriate ratio of pigment to base. Then I would apply the mixture to the bottom of the cleats and see which one works the best for a thermochromic shoe.

The news article we read indicated that 122 degrees F (50 degrees Celsius) or higher would be too hot for playing soccer. In you background reading, did you find any additional information? What temperature do you need to use for a threshold?

Do you think the 86 degree F thermochromic pigment would provide any useful information for a soccer shoe application? If not, then contact the company tomorrow and ask if there is anything available for a higher temperature cut off or if it would be possible to develop a custom product, The phone number is 772-237-3544 and they are in Florida (EST). You could send an e-mail inquiry today.

For a science project you will have to report results in degrees Celsius in your report and on your display board.

Your idea about applying the pigment with lacquer sounds reasonable. How are you going to tell which option works best? In a science project, you need something measurable.

Donna

In my background reading I have found that the artificial turf is roughly 50 degrees hotter than the surrounding air temperature. The average temperature of a field during the afternoon is 48 degrees celcius. In the shade being around 30 degrees celsius. I found four pigments with different activation temperatures.
1. 15 degrees celcius
2. 31 degrees
3. 47 degrees
4. 69 degrees
Will these activation temperatures be more suitable for the experiment?
I will tell which option works best by having all the pigments in contact with the turf for the same amount of time. This will ensure that they all absorb the same amount of heat energy. Which every pigment changes the fastest and has the most drastic change in the short amount of time will be the best option. Is this measurable??

Hi Soccerstar910.

47 degrees Celsius is 116 degrees Fahrenheit, so this seems like this would be a good choice. It will be helpful if you could have something that will warm up the turf in a controlled setting so you can measure the termperature and observe the color change. Otherwise, you will have to wait for a sunny day and wait for the turf to warm up.

You will be measuring the temperature and documenting the color so these are two measurable parameters, exactly what you need for a science project. . When you get the thermochromic pigment, see if you can match the colors to a color standard so you can compare the colors on the soccer shoes to a defined color. Or, better, investigate the possibility of using a cell phone color matching app to document the color.

https://www.sherwin-williams.com/homeow ... ap-mobile/

Donna

I got the cell phone app and it will work perfectly for the experiment. What temperature should the turf be if I were to warm it up in a controlled setting? Should I use the average temperature the artificial turf would be on a sunny day?

Hi,

Great! I'm glad the cell phone seems to work well. When you get to the science fair, tell the judges that you would have preferred to use a scanning spectrophotometer, but one was not available. Do some background research on the cell phone app and see if you can find any data on speed and accuracy, and in your discussion section, do include a paragraph comparing the two methods.

You will want to measure the color of the thermochromic pigment both below and above 47 degrees C. I recommend using the range of temperatures normally found at soccer games and record both the temperature and the color throughout the entire range. . Your graph will have temperature on the x axis and color on the y axis. You should make a note of the weather, if it is sunny, cloudy, raining, windy, or any other possible conditions that might affect your results. You should measure the air temperature and the turf temperature. ''https://www.sciencebuddies.org/science- ... tml#sample

What is the accuracy of the thermometer you will be using?

Donna

So am I testing all four pigments or just the one with the activation temperature of 47 degrees? Do I test all four pigments on a few temperatures below and a few above 47 degrees and make a separate graph for each one? I will be using a space heater to heat the turf and an infrared thermometer to measure the temperature.

Hi,

A space heater to heat the turf and an infrared thermometer should work very well.

You need to do an experiment with one independent variable, so you have a choice on what to do. .

You could get all four pigments and test them over the entire temperature range to verify they would work. This would yield a rainbow soccer shoe should that would be useful for any temperature range.

You could test four different concentrations of the 69 degree C pigment (or all of the pigments) to optimize the amount of pigment needed per shoe.

You could test one concentration of dye and use four different lacquer/glue/etc to apply the dye.

For each experiment, you would include one shoe or section of shoe with no dye as a negative control.

You can probably think of another possible experiment. Before you decide, think of a good question to ask that would be answered by your experiment.

Since you are new to working with thermochromic dyes, I recommend doing a small trial run to practice the experiment. This will facilitate the final experiment.


Donna