Superior Superconductors
Interpret authentic lab data on material characteristics and make recommendations for future research on superconductors
Background
Perhaps in elementary school, you learned that there are two categories of things when it comes to electricity: things that let electricity through (conductors) and things that don’t (insulators). Each material has a different ability to conduct electricity, with some being amazing at insulating and others amazing at conducting.
Even when we choose a fabulous material to use as a conductor, there are still some problems: the metal heats up or wears out over time. If this happens in an inexpensive product that we don’t need to last very long (e.g. a flashlight) it’s not really that much of an issue. But what about really expensive things that we NEED to last a long time — like things we’re sending into space? When we can’t access or replace circuitry easily, we need them to last as long as possible.
Enter stage left: superconductors! When metals are brought to extremely cold temperatures, their efficiency becomes almost perfect. We no longer have a heating or wearing-out problem in the same way we did before. Additionally, these amazing — “SUPER” — conductors create the most incredible electromagnetic induction, theoretically floating massive weights centimeters above the superconductor just because of how easily the electrons are flowing…incredible. (see a video of this happening!)
So why aren’t superconductors just littering the streets with their power? The issue arises when we have to actually get them down to extremely low temperatures. The amount of energy and engineering to create an environment cold enough (“high temperature” superconductors are considered functional at 30K, or -405 degrees F) is incredibly difficult. But scientists are continuing to investigate different materials, and trying to determine if there is any kind of pattern between critical temperature (when a metal goes from an ordinary conductor to a superconductor) and any other molecular characteristics.
In this activity, you will take a look at some real-world data and determine if there are any correlations between elemental characteristics and the potential to be a quality superconductor.
Dataset
This dataset was gathered from the UCI Machine Learning institute and the data has been simplified for our activity by viewing only the means for variables with replicate observations in the dataset. Students or teachers can view the dataset in its entirety by visiting the website, or view the original research paper here.
Variables
Number of elements - This numeric variable describes how many elements were combined to create the sample metal.
Mean atomic mass (AMU)- This numeric variable describes the mean atomic mass value for each of the combined elements in the sample metal. Measured in atomic mass units (AMU)
Mean density (kg/m^3) - This numeric variable describes the mean density value for each of the combined elements in the sample. Density is calculated by taking mass and dividing by volume. Measured in kilograms per meters cubed (kg/m^3)
Mean electron affinity (kJ/mol) - This numeric variable describes the mean amount of energy change experienced for each element when an electron is added to the atom. (Note: this value is calculated when the atom is in a gaseous state only). Measured in kJ/mol.
Mean fusion heat (kJ/mol) - this numeric variable describes the mean value for the amount of energy needed to change each element from a solid state to a liquid state without a temperature change (also known as heat of fusion). Measured in kJ/mol.
Mean thermal conductivity (W/m*K) - this numeric variable describes how well a material conducts electricity (or heat). This is the mean value for each element. It is measured in Watts / meter*Kelvin (W/m*K).
Mean Valence - this numeric value is the mean of each element’s number of valence electrons, or the number of chemical bonds formed by the element. There are no associated units.
Critical Temp (K) - this numeric value is the value in which the metal becomes a superconductor. It is measured in degrees Kelvin (K).
Activity
As we think about what data will be important to us, consider the goal of what makes an optimal superconductor. Which variables directly relate to how superconductors function? Ideally, do we want the value to be high or low in a good superconductor?
Part I: Evaluate all variables
2a. Begin to explore which graphs seem to show a pattern or relationship between the variables. Make a scatter plot, with critical temp as your y-axis variable, and mean Density on the x-axis. Screenshot your graph and include it below:
2b. Do you see a pattern from this graph?
2c. If you answered “yes” for 2b, list the optimal value for Density in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
3a. Make a new scatter plot, with critical temp as your y-axis variable, and number of Elements on the x-axis. Screenshot your graph and include it below:
3b. Do you see a pattern from this graph?
3c. If you answered “yes” for part B, list the optimal value for Number of Elements in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
4a. Make a new scatter plot, with critical temp as your y-axis variable, and fusion Heat on the x-axis. Screenshot your graph and include it below:
4b. Do you see a pattern from this graph?
4c. If you answered “yes” for part B, list the optimal value for Heat of Fusion in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
5a. - Make a new scatter plot, with critical temp as your y-axis variable, and Electron Affinity on the x-axis. Screenshot your graph and include it below:
5b. Do you see a pattern from this graph?
5c. If you answered “yes” for part B, list the optimal value for Electron Affinity in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
6a. - Make a new scatter plot, with critical temp as your y-axis variable, and Valence on the x-axis. Screenshot your graph and include it below:
6b. Do you see a pattern from this graph?
6c. If you answered “yes” for part B, list the optimal value for Valence in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
7a. Make a new scatter plot, with critical temp as your y-axis variable, and Thermal Conductivity on the x-axis. Screenshot your graph and include it below:
7b. Do you see a pattern from this graph?
7c. If you answered “yes” for part B, list the optimal value for Thermal Conductivity in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
8a. Make a new scatter plot, with critical temp as your y-axis variable, and Atomic Mass on the x-axis. Screenshot your graph and include it below:
8b. Do you see a pattern from this graph?
8c. If you answered “yes” for part B, list the optimal value for Atomic Mass in order to achieve the best critical temp for a superconductor. If you answered “no”, describe your decision using evidence from your graph.
9. Based on your graphs, what recommendations would you make for future study on superconductors? What kinds of elements should scientists look at in order to have the best chance at finding a metal with a high critical temp? Summarize all your findings below: