About this video

• Video Title: The Blender Question Everyone Gets Wrong
• Channel: Veritasium
• Speakers: Derek Muller
• Duration: 20:13

Overview

This video explores the famous Google interview question about being shrunk to the size of a nickel and placed in a blender. It examines various proposed solutions, discusses the physics and biology involved in surviving such a scenario, and ultimately reveals what interviewers were truly looking for when asking this type of question.

Key takeaways

• The Blender Question: A common Google interview question asks what you would do if shrunk to nickel size and placed in a blender with blades set to spin in 60 seconds.
• Initial Attempts: Common answers include hiding, breaking the blades, or trying to tip the blender over. These are generally considered incorrect or insufficient.
• Physics Principles: The video delves into concepts like Van der Waals forces (gecko effect), friction, and the square-cube law. It explains why smaller creatures are relatively stronger due to their higher strength-to-weight ratio.
• The "Jumping" Solution: Based on the square-cube law, a shrunk human would be proportionally much stronger and could potentially jump out of the blender. This requires the person to be around 2 cm tall and need to jump 30 cm.
• Complicating Factors: Air resistance, lack of coordination during the jump, and the biological limitations (heart, lungs, brain size) of a shrunken human are discussed, suggesting that survival might still be unlikely despite the increased strength.
• Interviewer's Intent: The true purpose of such brain teasers was not to find a correct answer, but to assess a candidate's ability to handle ambiguity, break down a problem, be creative, demonstrate intelligence, and communicate effectively.
• Evolution of Hiring: Google eventually realized that brain teasers were a waste of time and did not predict job performance, leading them to abandon such questions.
• Value of Thought Experiments: Despite their ineffectiveness in hiring, these types of questions can stimulate critical thinking, encourage new perspectives, and lead to scientific discoveries, as seen with historical examples like Einstein and Schrödinger.

The video explores several potential solutions to the blender problem, but ultimately highlights that the most scientifically plausible (though still debated) solution involves jumping out of the blender.

Here's a breakdown of why this is presented as a strong possibility:

• The Square-Cube Law: When a person is shrunk, their volume (and thus weight) decreases with the cube of their size, while their muscle strength, which depends on cross-sectional area, decreases with the square of their size. This means a significantly smaller person would have a much higher strength-to-weight ratio.
• Jumping Ability: Due to this increased strength-to-weight ratio, a person shrunk to the size of a nickel would have the proportional strength to jump much higher than their own body size would suggest.
• Calculations: Simulations discussed in the video suggest that a person shrunk to about 2 cm tall could potentially jump around 30-40 cm high, which would be sufficient to clear the walls of a blender.

However, the video also adds crucial caveats:

• Air Resistance: While drag is less significant than strength at this scale, it can still reduce the jump height.
• Coordination and Aerodynamics: Flipping or attempting a complex jump (like a backflip) would greatly increase air resistance and likely cause the person to fail. A simple, direct jump is key.
• Biological Realities: More critically, the video discusses how biological systems like the heart, lungs, and brain might not function correctly at such a small scale, potentially leading to death before a jump could even be attempted.

So, while the "jump out" answer is presented as the most likely physical solution based on scaling laws, the video ultimately questions whether a shrunken human could even survive long enough to attempt it.