# What Are All Those Quarks Doing in Your Body?

We're made of flesh and bone and fat, which are in turn made of protons and electrons, which are (mostly) made of quarks. Which, even though they are the most basic form of matter, are a minuscule percentage of your body's mass. Wait, what? Why do we have so much more mass than what we're made of?

# The Staggering Mass of the Craft We've Sent Into Space, Visualized

Ever tried to picture how much one rocket weighs compared to another, or how heavy some of the craft orbiting our planet really are? Well this chart explains all.

# Forget What Your Teacher Said: Mass and Weight Are the Same

At high school, your physics teacher probably drummed it into you that mass and weight are completely different thingsābut actually, they were wrong all along.

# Why does relativity mean that mass changes with speed?

Everyone knows that relativity plays hell with time, and that it can do a number on space, but what about mass? Why do objects get more or less mass depending on their relative speed? We're going to give you a quick explanation of why running can make you gain weight. No, we don't think it's fair either.

# How much does a shadow weigh?

Then again, a better question might be "how much less does an area covered in shadow weigh relative to surrounding areas covered in light?"

# The most sensitive weight scale ever can weigh individual protons

A new subatomic weight scale can measure masses as tiny as one yoctogram. Less than the mass of a proton, a yoctogram is equivalent to a billionth of a billionth of a millionth of a gram.

Mustachioed UC Berkeley computer science professor John Kubiatowicz told the NY Times that your Kindle gets heavier when you add e-books. Don't worry, though, you won't feel it with your hand, or with any scale that we've ever created.

# China Is Using a New Method to Mass Produce Healthier Water

In an effort to produce mass quantities of healthier H2O, Chinese scientists have come up with a new method to change water's chemical composition. It involves making light water.

# iPad Now Magical and Holy Thanks to Digital Missal

iBreviaryāthe daily prayer book for iPhoneāwill become a full Roman missal for iPad, allowing priests to celebrate mass in English, French, Spanish, Italian, and Latin. The Vatican-sanctioned application, created Padre Paolo Padrini, includes:

# Mass Extinctions Rise Among Plant Species

Entire species of plants are dying off in droves, just like mammals. And there's no way to save them all, say scientists. How do you decide which plant species to preserve at all costs, and which ones to consign to oblivion forever? Answering that question may mean the difference between selective extinction for someā¦

# Nanotube Scale Weighs One Atom at a Time

Yesterday we got a peek at the combined power of nanotubes-technology that makes a rope-driven space elevator feasible-but what can just one do on its own? Berkeley researchers have discovered that one nanotube can be used as a tiny platform to determine the mass of a single atom.