Category Archives: Q & A

eraser gif

How does an eraser work?

What happens when you write?

Although we call the black stuff in pencils “lead,” it’s not the real metal known as lead. It’s actually a mineral called “graphite,” which is made up of carbon. When you write with a pencil, graphite particles from the pencil rub off and stick to the fibers of the paper you’re writing on.

What do erasers do?

When you rub an eraser across a pencil mark, the abrasives in the eraser gently scratch the surface fibers of the paper to loosen the graphite particles. The softeners in the eraser help to prevent the paper from tearing. The sticky rubber in the eraser grabs and holds on to the graphite particles.

The physics

Erasers work because of friction.

As the abrasives in your eraser are rubbed against paper, friction produces heat, which helps the rubber become sticky enough to hold onto the graphite particles. As the rubber grabs the graphite particles, small pieces of combined rubber and graphite get left behind. That’s the “stuff” you brush off of your paper when you’re finished erasing.

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Questions and Answers: The Higgs Boson

As I told you shortly before, we’ll be answering all questions we receive from you guys on the site here, so everybody can benefit; again, if you have any scientific questions, to throw them our way and we’ll get them as soon as possible

Question: What the heck is a Higgs Boson, and why should we care?

This one’s tricky. First of all, we don’t know if the Higgs boson is real; if it were real, it would be an elementary particle, meaning that it has no other substructure – it isn’t built of anything else, it is one of the building blocks of the Universe.

We don’t know a lot of things about the Universe we live in, but we’re trying to figure them out. That’s why physicists postulated the Standard Model: a theory concerning electromagnetic, weak, and strong nuclear interactions, which, if proven true, would solve a lot of questions about regarding the particle world. So far, the Higgs boson is the only particle predicted in the Standard Model which hasn’t been found yet, so confirming or disproving its existence would be very important for our understanding of particles; it would be a huge step forward in the world of physics, and although there are no practical direct benefits, in the long run, we will greatly benefit from this discovery.

Answering our readers: The Earth’s core

I’ve been receiving questions from you people for years now – and really, this made me happy, because it says that people want to learn and understand more. But I’ve been answering them individually, and now, I’m thinking it would be better to post the answers on the website, so more people can read them. So, starting today, we have a new category, in which we’ll be doing just this; also, I’d like to take advantage of this to encourage you to send any scientific questions you might have, regardless of how silly you might feel they are – we’ll do our best to answer them. I’ll post a shorter version of the question.

Question: Why is the core so hot, and is it connected in any way to fossil fuels?

No, it’s not connected in any way to fossil fuels; fossil fuels are located in the crust at (generally speaking) several kilometers blow surface, and the core is at 5150 kilometers beneath surface. Let’s detail.

For starters, we’ll be discussing about Earth’s core. The Earth’s core is made of two parts: a solid inner core and a liquid outer core. The outer core has a temperature of 4400 °C – 6100 °C, while the inner core has an average of 5505 °C – which is about as big as the temperature on the surface of the Sun – and there are a number of reasons why this temperature is so high.

Generally speaking, the temperature rises as you’re going towards the inner core, growing with pressure. Earth has a significant amount of heat left over from when it fist condensed as a planet; sure, we’re walking around here find and dandy, but the depths of the Earth haven’t had enough time to cool down. This amounts for about 5-10 percent of the heat. Gravitational heat matters about just as much. What is gravitational heat? Well imagine our planet, in its initial stages, as a huge mass of lava (or honey, if that works better for you). If you put, say, a rock in a jar of honey, it will go down. The same thing happened with the Earth: the denser elements went down towards the core, and this movement continues today, causing friction which generates heat.

Then you have latent heat, which arises as the Earth cools from inside out; liquid metal solidifies, releasing heat in the process. But by far, the most important source of heat our planet has comes from radioactivity (mostly in the mantle). Radioactive decay causes up to 90 percent of all the heat inside our planet! There’s a good chance sometime in the future our planet will cool enough to fully solidify, and will become ‘dead’, much like the Moon. However, before this happens, the Sun will grow into a red supernova so large that it will also engulf Earth – so any heat in the mantle will hardly matter.