"Wisdom begins in wonder" – Socrates
Category: Physics
Leachates
02/01/26
“What happens when liquid picks up dissolved/suspended solids as it moves through a permeable layer?”
Liquids can move through permeable layers. Sometimes, the layer may have soluble or suspended solids along its journey and form what’s called a Leachate. Leachate properties are dependent on the liquid and its solvent. Leachates from stormwater landing on landfills can pollute nearby surface and groundwater.
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Fluid Pressure Diagrams
01/31/26
“How can we visualize how fluid pressure changes with depth?”
Fluids increase in pressure as you get deeper. If the fluid has a non-uniform density with depth, then the pressure will increase differently at different heights. We can visualize this information with a Fluid Pressure Diagram, which graphs depth on the negative y-axis and pressure on the x-axis. Fluid pressure diagrams are a great way to find out what the force on an area of the fluid container is because you can integrate the fluid pressure diagram and multiply by surface area.
Noise Dose
01/24/26
“How can we quantify the level of noise someone is exposed to over time?”
Listening to too much loud noise is a well-known safety risk. The constant vibration in your ears can lead to long-term damage if not managed properly. The Noise Dose quantifies how much noise a person has been exposed to for the day, regarding safety levels. We can quantify noise dose by taking the hours someone listened to a certain decibel of noise and dividing it by the maximum number of hours it’s safe to listen to that noise level per day. We can sum this ratio for every noise decibel level heard throughout the day, multiplied by 100% to arrive at the total noise dose. If a noise dose exceeds 100 percent, then the person has breached the healthy recommended daily noise levels.
Saturation Pressure
01/08/26
“What is the pressure at which a substance’s liquid and vapor phases are balanced with each other?”
Vapors form when molecules from a liquid bounce into the air as gases. At some pressures, more molecules escape, and at others, more return. The pressure where the molecular exchange between each phase is equal is known as the Saturation Pressure. The saturation pressure is dependent on temperature, since higher temperatures mean more molecules escape, necessitating a higher pressure to keep them contained. Saturation pressure dictates what the vapor makeup of a mixture will appear according to Raoult’s law.
Electrodialysis
10/17/25
“How can we use electric potential to desalinate water?”
Saltwater is much more common than freshwater in the world. Consequently, we could greatly increase our water supplies by converting saltwater to freshwater. But traditional reverse osmosis techniques are incredibly energy-intensive. Is there an easier way to desalinate water? Well, we know that salts have an electrostatic charge. So what if we were to place the water stream between a cathode and an anode and insert an alternating series of membranes that only allow cations or anions to pass? Well, this will create streams of purified water, separated from saltwater. This process, called Electrodialysis, is a smart way to desalinate water and make it useful for people.
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Mass Transfer
10/12/25
“How does mass move from one phase/substance to another?”
Substances in different phases or substances may come into contact with each other. This can cause the mass of a certain substance in one phase or concentration to move to another, such as through diffusion (one substance moving from a single concentration in another to uniform distribution), convection (mass transport by bulk motion of a surrounding fluid), absorption (chemical penetration of one substance into another), or distillation (separation of different components by different boiling points). This Mass Transfer is foundational to understanding how chemical engineering systems operate.
Osmotic Pressure
09/30/25
“What’s the pressure needed to stop osmosis?”
Imagine a semi-permeable layer dividing a container of freshwater from a container of saltwater, each with equal volumes. Now imagine that the semi-permeable layer is small enough for water particles to pass through, but not for salt particles. Since there are more water particles on the saltwater side than on the freshwater side, there will be a water particle migration until there’s an equal amount on both sides. This will lead to a pressure differential in the direction of the salt water. The pressure necessary to overcome this imbalance and begin the reverse osmosis process is called the Osmotic Pressure, given by the equation pi = phi * (n/V)RT, where pi is the osmotic pressure, phi is the osmotic coefficient, n is the number of moles in the solute (in this case, salt), V the volume of the solvent, R the universal gas constant, and T the absolute temperature.
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Distillation
09/29/25
“How can we use boiling to separate two substances mixed together?”
Substances mixed together in a liquid can be difficult to separate. But applying a bit of chemical knowledge can help us. If the two mixtures have significantly different boiling points, then one will vaporize before the other. So what if we were to capture this vapor and condense it into another reservoir to separate the substances? Well, this is the idea behind Distillation. Water treatment systems can apply distillation to separate water from contaminants. If the boiling points between the different substances are less than 100 degrees ˚C apart, then operators must use a special fractional distillation technique.
Henry’s Law
09/28/25
“What describes the relationship between the amount of gas dissolved in a liquid and the partial pressure above the liquid?”
Pressure forces gas to move. If gas is in a container with a liquid and high pressure is acting on the gas, there is more force to move more of the gas into the liquid. If there is low pressure acting on the liquid, then more of the gas will escape from the liquid. This behavior is described by Henry’s Law, which is described by the formula C = k_H*P, with C being the concentration of the gas dissolved in the liquid (mol/L or mg/L), k_H the Henry’s Law constant (mol/liter-atm or dimensionless), and P the partial pressure of the gas in the air above the liquid (atm). Henry’s Law is a vital part of mass transfer analysis for many applications.
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