# Tag: biophysics

## visible light – Why is the sky not purple?

The Question : 69 people think this question is useful I realise the question of why this sky is blue is considered reasonably often here, one way or another. You can take that knowledge as given. What I’m wondering is, given that the spectrum of Rayleigh scattering goes like $\omega^4$, why is the sky not

## biophysics – How can ants carry items much heavier than themselves?

The Question : 71 people think this question is useful This morning I saw an ant and suddenly a question came to my mind: how do ants actually carry items much heavier than themselves? What’s the difference (in physics) between us and them? The Question Comments : But i mentioned ,in physics… I dont want

## biophysics – Does quantum mechanics play a role in the brain?

The Question : 78 people think this question is useful I’m interested in whether the scale of processes that occur in the brain is small enough to be affected by quantum mechanics. For instance, we ignore quantum mechanics when we analyze a game of tennis because a tennis ball is much too large to be

## nuclear physics – Why can Hiroshima be inhabited when Chernobyl cannot?

The Question : 85 people think this question is useful There was an atomic bomb dropped in Hiroshima, but today there are residents in Hiroshima. However, in Chernobyl, where there was a nuclear reactor meltdown, there are no residents living today (or very few). What made the difference? The Question Comments : Actually Chernobyl is

## Why does holding something up cost energy while no work is being done?

The Question : 150 people think this question is useful I read the definition of work as $$W ~=~ \vec{F} \cdot \vec{d}$$ $$\text{ Work = (Force) \cdot (Distance)}.$$ If a book is there on the table, no work is done as no distance is covered. If I hold up a book in my hand and