Kate the Chemist on Cosmic Chemistry and Earthly Experiments

Kate Biberdorf explained that she wrote her book, 'The Awesome Book of Edible Experiments for Kids,' during the COVID-19 pandemic to maintain her sanity. She found inspiration by examining her pantry, considering how everyday items could be transformed into science experiments.

The experiments primarily focused on baking, a pastime Biberdorf enjoys more than general cooking. She noted the extensive chemistry involved in baking, making it a natural fit for her goal of making science accessible and fun using household ingredients.

Kate Biberdorf discussed the evolving scope of her podcast, 'Seeking a Scientist,' which initially had a strong sci-fi focus but has transitioned to exploring a wider array of scientific inquiries. One notable episode featured an interview with Kate Rubins, the first person to sequence DNA in space.

The podcast also delves into complex topics like plant intelligence, prompting a discussion about what it means to be intelligent. Biberdorf's team examined how plants communicate through underground mycelium networks. While co-host Neil deGrasse Tyson expressed initial skepticism, Biberdorf indicated that defining intelligence opened her mind to the possibility of plant communication systems.

Kate Biberdorf clarified the scientific impossibility of 'liquid diamond,' explaining that a diamond is a solid structure of carbon. She stated that referring to 'liquid diamond' is a contradiction, similar to saying 'liquid solid,' because they represent distinct phases.

The carbon phase diagram illustrates four different states: gas, liquid, and two solid phases, diamond and graphite. While liquid carbon is a real state, swimming in it would be impossible due to extreme conditions, including temperatures and pressures around 10,000 atmospheres. Under such conditions, a person would instantly vaporize.

Biberdorf emphasized that if diamond were to melt, it would undergo a phase change and no longer be classified as diamond.

Biberdorf explained that melting a diamond involves a phase change from a solid to a liquid state, meaning it is no longer defined as diamond. Diamond is a network solid composed of carbon atoms covalently bonded to other carbon atoms. When it transitions to a liquid, the spacing between these carbon atoms changes.

She noted the complexity of the question but affirmed that the transformation alters the fundamental properties of the substance.

Biberdorf suggested that the term 'liquid crystal' often involves a loose use of language in a scientific context. She explained that it likely refers to a substance that retains a crystal structure but has an increased distance between its atoms or molecules, possibly due to thermal or electrical components affecting its molecular arrangement.

She drew a parallel between the term 'liquid crystal' and 'liquid diamond,' indicating both combine terms that refer to different states of matter or properties. She highlighted that chemical stability is distinct from appearance, and phenomena like temperature-dependent molecular rearrangements could explain the visual changes in liquid crystal displays.

Biberdorf debunked the idea of 'crystal energy' for healing, explaining that a crystal represents the lowest energy state of its constituent atoms or molecules. Therefore, crystals cannot release energy to cure ailments.

She affirmed that from a scientific standpoint, a crystal is the least effective substance one could choose to claim healing properties due to its inherent stability and minimal energy. Comparatively, a gas would possess more energy than a crystal structure.

Biberdorf clarified that while crystals are generally stable, their stability varies depending on their bonding. Sugar crystals, for instance, rely on weaker intermolecular forces like hydrogen bonding and dispersion forces. In contrast, salt, an ionic solid, consists of repeating sodium and chloride ions that form stronger bonds.

Diamond, a network solid, uses entirely covalent bonds, which are generally stronger than ionic bonds, while both are stronger than dispersion forces. This general trend indicates that covalent and ionic solids are more robust than substances bonded by weaker intermolecular forces, though exceptions exist.

Kate Biberdorf posited that if extraterrestrial life exists within this universe, it would likely be based on the same fundamental building blocks and utilize the same elements as life on Earth. She emphasized that carbon is the primary candidate for a biological base due to its exceptional ability to form stable molecules.

Biberdorf acknowledged silicon as a potential alternative, given its position in group four of the periodic table, making it a 'cousin' to carbon in terms of chemical behavior. However, she expressed surprise if life were not carbon-based.

She also noted that water would likely be a universal solvent, with the caveat that life on planets with extreme temperatures or pressures might necessitate alternative solvents if water is constantly in a solid form. While the elemental building blocks may be consistent, she suggested that the specific details, such as DNA, RNA, or amino acids, could differ in extraterrestrial life forms.

Neil deGrasse Tyson, however, was less convinced by the silicon argument, pointing out that carbon is at least five times more abundant than silicon in the universe, making it a more statistically probable foundation for life.

Biberdorf explained that while numerous alternative periodic table organizations exist, the current one, based on Mendeleev's design, is widely adopted because of its practical utility. It effectively highlights crucial information, such as valence electrons, which is essential for understanding chemical behavior.

Mendeleev's original design was validated by its ability to predict the properties of then-undiscovered elements like gallium and germanium, leaving spaces for them in the table. Although other organizational principles, such as atomic mass, nuclear stability, conductivity, or cosmic abundance, could be used, the current periodic table remains the easiest to interpret and most informative for chemists.

Biberdorf explored whether life might not depend exclusively on liquid water, but on any liquid able to carry nutrients and overcome solubility problems. In that context, she raised methane as a possible solvent for life on moons such as Titan, speculating that life there could evolve to use its reactivity. Her suggestion was an open idea rather than a settled claim.

She indicated that for life to use methane, it would need to contend with the 'fire triangle' components: fuel, oxygen, and an energy spark. Biberdorf also highlighted that Earth's life, with its liquid water and 'melted rocks,' might appear just as alien to life forms accustomed to environments where rocks themselves are liquid.

The key, she noted, lies in finding a solvent with suitable polar and non-polar properties that could facilitate the circulation of molecules essential for life in extreme temperature regimes.

Biberdorf explained the concept of the 'fire triangle,' which illustrates the three essential components required for a fire: fuel, oxygen, and an ignition source (like a spark or heat source). She emphasized that removing any one of these components will prevent a fire from occurring.

A physicist clarified that while a spark is a common ignition source, any sufficient energy source can trigger the bond rearrangement necessary for combustion. Biberdorf concurred, noting that from a chemistry perspective, energy is needed to break existing bonds and form new ones, which is what happens during a fire.

Biberdorf expanded on the 'fire triangle' by introducing the 'fire pentagon' for dust explosions, which adds two more critical components: a confined area and fuel in particulate matter form. This phenomenon is often observed in environments like sugar factories, where fine dust particles can accumulate.

She explained that a small initial spark can trigger a minor explosion, which then disturbs more dust, leading to a much larger and more dangerous secondary explosion. The combination of fuel, oxygen, an energy source, confinement, and particulate fuel creates conditions for devastating blasts.

Biberdorf explained the classic experiment of boiling water in a paper cup without burning the cup. The paper cup remains intact because the paper itself maintains the same temperature as the water it contains. The water absorbs the heat energy from the flame, preventing the paper from reaching its ignition temperature.

She clarified that the paper cup would only begin to burn if the water evaporated down to the level of the flame, at which point the paper would no longer be cooled by the water and could then reach the flame's temperature. This experiment effectively demonstrates principles of heat transfer and temperature limits.

Biberdorf detailed the 'exploding paint can' experiment, which involves placing about an inch of baking soda at the bottom of an empty paint can. A plastic cup containing approximately a cup of vinegar is then nested into the baking soda.

The can is sealed tightly with its lid, ensuring no gas can escape. When shaken and slammed onto a table, the chemical reaction between the baking soda and vinegar generates gas pressure, forcefully launching the lid into the air. The height the lid reaches can vary from about a foot for smaller containers to 5-10 feet for a typical gallon-sized paint can, depending on the scale of the reaction and the size of the can.

Biberdorf stressed the importance of safety gear for chemical demonstrations, particularly those involving dry ice. She mandated the use of cryogenic gloves, goggles, and a lab coat for such experiments. For those without specialized cryogenic gloves, she recommended using thick work gloves, such as those found at hardware stores.

These safety precautions are crucial even for seemingly simple demonstration setups. For an experiment involving dry ice and a kiddie pool to create a 'white tornado,' she advised setting up four to six box fans around the pool at a 75-degree angle to create a vortex. However, she reiterated that safety equipment must always be worn when handling dry ice.

Biberdorf addressed a common misconception that exhaled human breath is 100% carbon dioxide, clarifying that this is false. She revealed that the actual concentration of carbon dioxide in exhaled air is only 4%.

Biberdorf also corrected a common misconception: most people think exhaled breath is nearly pure carbon dioxide, but it actually contains only about 4% carbon dioxide. She explained that this matters for CPR, since if exhaled air were 100% carbon dioxide, rescue breathing would not work; the breath still carries enough oxygen, along with a large share of nitrogen. She added that carbon dioxide is nonetheless everywhere in the atmosphere and is a major driver of climate change.