Why You Should Love Density | Will Grover | TEDxUCR

Summary

In this engaging talk, the speaker shares personal anecdotes about the scientific curiosity instilled by his scientist parents, leading to a fascination with density. He explains how density, a measure of mass per unit volume, can reveal hidden properties of objects, from distinguishing healthy from sick cells to identifying materials. The speaker's work at MIT and UC Riverside explores using density to detect diseases like malaria, assess the effectiveness of cancer drugs, and monitor environmental health. The potential applications of density measurements are vast, from medical diagnostics to environmental safety.

Takeaways

• 👨‍🔬 The speaker, a scientist, shares personal anecdotes about growing up as the child of scientists and how they conducted experiments on him.
• 🔬 The speaker demonstrates the concept of density through an experiment with two cubes that look identical but have vastly different weights, illustrating the importance of density in distinguishing objects.
• 🧠 Density is defined as mass divided by volume, and it provides more information than either mass or volume alone, which is crucial for understanding the properties of objects.
• 🌍 Density varies widely on Earth, from 0 g/mL for gases to 22-23 g/mL for the densest elements like osmium and iridium.
• 🎈 The density of gases like helium and air is used to explain why helium-filled balloons float, demonstrating density's practical applications.
• 🛠️ Density can be used to identify substances, as shown by the difference between aluminum and tungsten blocks, which look similar but have distinct densities.
• 🏺 The historical example of Archimedes using density to determine the composition of the king's crown is recounted, highlighting the age-old utility of density measurements.
• 🏋️‍♀️ Density measurements are relevant to health and biology, such as assessing body fat percentage and distinguishing between healthy and diseased cells.
• 🧬 The speaker's research at MIT involved using density to differentiate between healthy and sick cells, including those affected by malaria or cancer, showcasing density's role in medical science.
• 🐟 Current research at UC Riverside explores the potential of density measurements in zebra fish embryos as an early warning system for environmental toxins, indicating density's broader ecological applications.

Q & A

What is the significance of the two cubes in the speaker's story?

The two cubes, although identical in appearance, differ significantly in weight, with one being almost ten times heavier than the other. This demonstrates the concept of density, which is a key theme in the speaker's narrative about distinguishing between similar-looking objects.

How did the speaker's son react when he was given the two cubes?

The speaker's son was surprised by the difference in weight when he was handed the second cube, which was much heavier despite looking identical to the first one.

What property of the cubes is used to distinguish between a healthy and a sick cell?

The property that distinguishes between the heavy and light cube, as well as between a healthy and sick cell, is density. The speaker discovered that density can be used to identify differences in cells that are not apparent through size and shape alone.

What is the range of densities encountered on Earth according to the speaker?

The range of densities on Earth spans from 0 grams per milliliter for gases like helium to about 22 or 23 grams per milliliter for the densest elements, such as osmium and iridium.

Why does the helium-filled balloon rise when released?

The helium-filled balloon rises because helium is less dense than air. According to the principle of buoyancy, objects with a lower density than the surrounding medium will rise.

How did Archimedes determine if the king's crown was made of pure gold?

Archimedes determined the purity of the king's crown by measuring its density. He compared the measured density of the crown to the known density of pure gold. If the densities matched, it indicated the crown was made of pure gold.

What method did the speaker's team use to measure the mass of single cells?

The speaker's team used a suspended microchannel resonator, a tiny mass sensor similar in principle to a baby bouncer, to measure the mass of single cells. This device allowed them to determine the cell's density by measuring its mass in two different fluids.

How does the density of red blood cells change when infected with malaria?

When red blood cells are infected with the malaria parasite, they become less dense. The parasite consumes hemoglobin, which results in a less dense form, thus reducing the overall density of the infected cells.

What insight can be gained from measuring the density of cancer cells after drug treatment?

Measuring the density of cancer cells after drug treatment can reveal changes that indicate the cells' response to the drug. An increase in density post-treatment suggests the drug is affecting the cells, potentially serving as a screening tool for drug efficacy.

What potential application does the speaker suggest for density measurements in zebrafish embryos?

The speaker suggests that density measurements in zebrafish embryos could serve as an early warning system, akin to a 'canary in a coal mine,' to detect harmful chemicals in water or air by monitoring changes in the density of the embryos.