Friction is the force resisting the relative lateral (tangential) motion of solid surfaces, fluid layers, or material elements in contact. It is usually subdivided into several varieties.

Already I’m like, WHOAH, what does THAT mean? I have no idea! That’s why sometimes I feel stupid, ’cause I read stuff on the internet when I just wanna find out a simple answer to a simple question like, “Why is ice slippery” and I get this sentence about relatives and ladders and tangerines. I don’t get it! But I really wanted to know, ’cause I been tryin’ to look things up like Mr. W says, so I tried the next link down at fearofphysics.com and that definition made WAY more sense:

Friction is the “evil” of all motion. No matter which direction something moves in, friction pulls it the other way. Move something left, friction pulls right. Move something up, friction pulls down.

Already I can tell a little more about Friction! It’s some kinda force that keeps you from moving one way ’cause it’s pushing the other way. That’s not so hard to understand. And when I read the rest of the definition, I could already kind of guess what the answer to my question was! Look, I made a practice question out of it:

Friction is the “evil” of all motion. No matter which direction something moves in, friction pulls it the other way. Move something left, friction pulls right. Move something up, friction pulls down. It appears as if nature has given us friction to stop us from moving anything. Friction is actually a force that appears whenever two things rub against each other. Although two objects might look smooth, microscopically, they’re very rough and jagged… As they slide against each other, their contact is anything BUT smooth. They both kind of grind and drag against each other. This is where friction comes from. — fearofphysics.com

Why can you slide on ice more easily than on concrete?

1. Concrete is evil.

2. Ice has more friction than concrete.

3. Concrete has more friction than ice.

4. Ice has no friction at all.

5. It’s impossible to know from this passage.

Since this is my practice question, I’ll let you guys figure it out! But I wanted to also say that, well, if at first you don’t succeed, try, try again! I mean, when I first tried to look up friction, I just didn’t get it. I think that if I was lookin’ this stuff up before I started studying for the GED, I woulda given up after the first try. I woulda thought I was an idiot! But I’m not! Even if I have to go to a site that’s meant for kids in middle school or something, I’d rather understand something that was explained really simplistically than not get it at all!

So everyone out there, keep trying and searching for answers to your questions! Eventually, you’ll find something that makes sense to you!

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

Check out this practice question I found about the GRAVITRON!

A man stands on a ride at an amusement park that spins around. As the ride spins faster, the man is pushed back against the outer wall and finds it very difficult to pull himself away from it.

Which statement best explains this event?

1. There is glue on the wall holding him on.

2. The ride is creating a magnetic force that pulls the man toward the metal in the walls.

3. The ride is creating a new center of gravity inside the walls.

4. The spinning of the ride creates a centrifugal force that pushes the man outward from the center.

5. The ride creates an optical illusion the makes the man think he is falling backward into the wall.

Haha, well unless he’s a metal man, I don’t think 2 is right! Magnetics only work on metal, and only some kinds of metal. Maybe if he had a lot of metal in his pockets? But the question doesn’t say he does, so I’m gonna guess not. Especially ’cause I don’t think spinning around creates magnetic forces, that has something to do with the north and south pole I think?

Anyway, 1 is always wrong, there’s no glue in theme park rides unless some kind puts it there. That leaves me with 3, which says it’s gravity; 4, which says it’s centrifugal force; and 5, which says it’s all an optical illusion. Well, I guess there are some optical illusions that make you think you might be moving when you’re not. They got this other ride at Universal Studios that has a long tunnel that spins, and when you get out of the tunnel, you realize that everyone on the ride is leaning to their left ’cause of the spinning! I don’t know how that works, but I don’t think it’s true here. When you spin something around, like if you had a cup filled with water and spun it really fast, the water would stick to the sides too! So that’s not it.

I don’t think it’s 3 either, ’cause gravity is something that big things do. The sun, the Earth, the moon, they all have gravity, but they’re big masses… I mean HUGE masses of rock and stuff, and they only create a little bit of gravity. I mean, we can still jump and fly in planes. But when you’re on the Gravitron, you couldn’t jump. It says that in the question too. “The man finds it very difficult to pull himself away.” So if the Earth creates a little bit of gravity, I really doubt the Gravitron could creation even MORE gravity (as much as its name wants it to).

I think the answer’s number 4. I’m not even entirely sure what centrifugal force is, but it sounds about right. Like isn’t a centrifuge something the put blood in and spin REALLY fast? Even if you don’t know about that, all the other answers just don’t make as much sense. Like 3 says it’s making gravity IN the walls, which doesn’t work, but 4 says that it’s creating a force that just pushes the man out from the center. That makes more sense.

Hope everyone has a good new year! 2010!! Keep studying for the GED! Make a resolution to pass! You can totally do it!

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

However, if it weren’t for the greenhouse effect, we’d all be ice statues! Check it out!!

Much of the Sun’s energy is absorbed by the Earth’s surface. When the ground heats up, it sends energy back into the atmosphere. The atmosphere absorbs the energy as well and some of it escapes up into space while some falls back down to Earth. This is called the greenhouse effect. This system of rising and falling energy is what keeps Earth warm enough for human life to exist.

Which of the following gives the best reason for calling this system “the greenhouse effect?”

1. Greenhouses have an atmosphere that is similar to Earth.

2. Both greenhouses and Earth have many plants.

3. There are tiny particles of glass in Earth’s atmosphere that trap the warm air.

4. There is no relation to the greenhouse effect and actual greenhouses.

5. The glass in greenhouses behave similarly to that of the Earth’s atmosphere.

The greenhouse effect is pretty kewl! I wish I lived in a greenhouse. Then I could lay out and get a sweet tan in January.

So, number one is totally bogus. Greenhouses are tiny little houses made out of glass. They don’t have an atmosphere!

Number two is totally true because Earth DOES have a lot of plants. And so do greenhouses. I mean, that’s what greenhouses exist for, right? But since the passage doesn’t say anything about plants, then that’s probably not the best answer. And it doesn’t say anything about there being glass in the atmosphere either. It just says that the atmosphere lets some of the sun’s energy escape, and bounces the rest back. Maybe it acts like glass, but there isn’t any actual glass in the air! Otherwise we’d all have some serious breathing problems!

Number four is bogus too. Come on, it’s called the GREENHOUSE effect. I mean, it COULD be just a coincidence that the two have the same name, but it’s unlikely. And check it out, number four doesn’t even ANSWER the question! “What is the reason they call it the greenhouse effect?” “There’s no relation between greenhouses and the greenhouse effect.” That doesn’t make sense! So, there’s no way that’s right.

Five is the best answer. Even if I’d never seen or been to a greenhouse before, everyone knows what it’s like to get in a car on a really hot day. The air inside is like 100 degrees hotter, dude! All because of the windows, right? That sounds a lot like how the atmosphere bounces back warm energy, so the glass in a greenhouse has got to do the same thing!

Stay warm while you’re studying, everyone. Maybe you should try to find a greenhouse to study in! Sweet!!

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

Kewl, right? I mean, if I could totally surf while taking the GED, I bet I’d do lots better. Only my answers’d be all wet.

Here’s what the article has to say:

The glorious sunshine and the Pacific Ocean provide the perfect conditions for Robert Liu and colleagues’ photochemical reactions, which use the sun’s rays to make variants of vitamin A.

The excess heat from the reaction is then effortlessly dissipated by the sea, presumably as the highly skilled chemist completes the reaction by riding a huge wave back to the beach.

Pop GED Practice Question!!!

A photochemical reaction creates a chemical reaction using….

A)  heat

B)  surfboards

C)  light

D)  water

E)  wind

Did you get the answer? You gotta look in the first paragraph of text up there… “photochemical reactions, which use the sun’s rays…” What are the sun’s rays? Wind? Water? Surfboards? Highly dubious, dude! You might think it’s heat, cuz the sun heats us up. But the sun’s rays are really light. Think about the word “photo…” like, a photograph uses light to make a picture, right? Well, a photochemical reaction uses light to make a chemical reaction. You might get a clue where it says “glorious SUNSHINE.” Dude, that’s definitely light.

Keep watching the science news for kewl stuff, and good luck on your GED studyin’!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.

Don’t believe me? Here’s a link to the science article:

http://news.bbc.co.uk/2/hi/science/nature/7553061.stm

See, here’s what it says:

Scientists in the US say they are a step closer to developing materials that could render people invisible.

Researchers at the University of California in Berkeley have developed a material that can bend light around 3D objects making them “disappear”.

Dude! It’s stuff that bends light. Weird. Wait, it’s kinda like a mirror, right? See, light hits the mirror and bounces off at the same angle… so looking in a mirror is like looking out of the mirror at yourself… weird.

So, you know that light can be  bent, right? It can hit a mirror and bounce off… cuz it bounces off at just the right angle, all the light rays stay together and you can see what’s behind you.

Same thing with this invisibility stuff… light rays hit you and usually they bounce off of you in different directions. But this stuff reflects the light rays AROUND you… not back where they came from, but back on track the same direction they were already going… so that no one sees you. Kinda like the Predator, right? You’re invisible because the light rays are the same when they leave you as when they hit you. Weird.

Light off a mirror is REFLECTED…bounced off. Light that’s moved around you like that invisiblity cloak stuff is REFRACTED… it passes through something… and it gets bent while it’s going through. Like, light gets refracted when it goes through water or stained glass or a prism. The trick is to refract the light just right so it ends up going out the same direction it goes in. Then, it’d be just like you were a piece of glass…invisible!

So, here’s your GED  science practice question…

Which of the following kinds of technology uses REFRACTED light?

1) A telescopic gun sight

2) A camera

3) Contact lenses

4) A microscope

5) All of the above

Do you know the answer… think about it…

I bet you got it… the answer is 5… all these things use refracted light, and soon the INVISIBILITY CLOAK will be on the list, too! Refracted light passes through something and gets bent as it goes on through…, so a telescopic gun sight bends the light so things look closer, just like a regular telescope or binoculars. And, a camera bends the light so that it gets on the film in the right size, so you can take a picture. And your contact lenses bend light so it puts everything in focus for your eyes, even tho your eyes are messed up, like mine. And, a microscope bends light to make little, tiny stuff look big so you can see it! So, bending light changes the way you see things.

And an invisibility cloak could bend light so you don’t see something at all!!! Kewl.

So, now you learned some GED science! Keep studyin’… that GED is pretty close, I bet!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.

Which one’s gonna be easier? Cuz, that’s the important thing. No one wants to work too hard, right? So, work smarter! Pick the easiest lever! Do it!

Answers:

A)    Lever A

B)    Lever B

C)    Both are the same.

You got your answer? Choose one now! Cuz I’m gonna explain it in a minute….

I’m waiting. You answered the question yet?

Oh, okay. Here’s the answer… it’s…  Lever B!!! Yes, answer B is correct. Did you get it right? Here’s why… and it’s pretty important to know for the test…

The amount of work you’re doin’ is equal to the amount of force you put on the lever (how hard you push down) times the distance from the fulcrum (that’s the triangle in the center!). So, the further away you are from the fulcrum, the more you’re adding to your force to do more work! Cuz you multiply it by the distance, the farther away you get from the fulcrum, the more distance you got, and the more work you do.

Same thing with the other side. You want to put your happy face as close to the fulcrum as possible, because it’s like you multiply how heavy it is by the distance from the fulcrum to figure out how much you gotta lift. It’s pushing down on the lever, right? You gotta push down harder to lift it. So you want its “pushing down”ness to be as small as possible (as close as you can get it to the fulcrum.) And, you want your “pushing down”ness to be as big as possible (as far as you can get  from the fulcrum). Get it?

Try this at home. Like, you can make a scale by tying a string in the center of a stick and hanging it from the ceiling. It’s just like a lever, but the fulcrum’s holding it up instead of on the bottom. Get it? Now, you can tie different things to each side to see which one’s heaviest. Try tying two identical things (like matching earrings) to the scale. If they’re the same distance from the center (fulcrum) the scale should balance.

If one’s farther away than the other, it pulls its side down. It’s like it’s heavier! That’s cuz the distance, not just the weight, is part of how it affects the lever. Kewl. Play around with it… that’s the best way to understand it, I think.

Happy GED learning!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passged.com or call 1-888-880-2164.

Here’s a link with a bunch of info on Van de Graaff Generators… http://hyperphysics.phy-astr.gsu.edu/hbase/electric/vandeg.html …

Well, it’s, like, a machine for taking electrons out of a metal ball at the top… and since electrons are NEGATIVELY charged, the ball at the top gets POSITIVELY charged. And if you touch that Van de Graaff generator thing… you can make your hair stand on end. Because the ball is positively charged, it wants some ELECTRONS! It gotta have them!!! So, when you touch it… it’ll take ELECTRONS from you. An’ what happens? You give up a bunch of electrons… an’ your hair is all POSITIVELY CHARGED now. So…

You know all about static electricity an’ all that. Here’s your question… why’s your hair stand on end?

1) the positively charged hairs are repelled from each other and your head

2) the positively charged hairs are attracted to the ceiling

3) the ball now has no charge because of the extra electrons, and pushes your positively charged hair away

4) the positively charged hair is lighter because it has fewer electrons and so it floats upward

Okay. Now, I’ll give you some time to answer. Dum, da…dum, da….dum, da, dum. Dum-da-dum-dum-dahhh–dadadadada… Times up!!! Did you get it? What did you think was the answer?

Drumroll please…. The correct answer… is… answer 1!!! Remember… OPPOSITES ATTRACT. And that means, SAMES PUSH EACH OTHER AWAY. If all your hair is positively charged, it all wants to get away from each other! So your pieces of hair push each other as far away as possible…and they stand up on end!!! Kewl.

Now for the fun part. You can build a  Van de Graaff Generator at home! Yes, you can! And weird out all your friends. Here’s instructions…. http://web.singnet.com.sg/~sengam/construction.htm

Have some kewl GED science fun!!!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.

Hahahaha!!! Did I SHOCK you? Because that’s what you probably got doin’ my experiment…an electric SHOCK. Yeah, it’s called static electricity. And don’t get mad…cuz it really is SCIENCE. That’s right…same kinda science that’s on the GED test.

So, what is static electricity? What’s the science behind the electric shock you get?

Here’s the deal: it’s all about attraction!!!

You’ve heard the saying, “Opposites attract.” Well, that comes from science. See, things like doorknobs and carpet and shoes and you are made up of atoms, and atoms are made up of electrons, protons, and neutrons.

Electrons are negative… they’ve got a “negative” charge.

Protons are positive… they’ve got a “positive” charge.

Neutrons are neutral. They stay out of it! They’ve got a “neutral” charge.

Well, the electrons are on the outside of atoms, and they’re movin’ around, all fast-like, goin’ here and there… and guess what? When you rub two things together, like your shoes and carpet, the electrons from one rub off on another! So, one ends up with too many electrons, and gets negatively charged. The other one ends up with two few electrons and gets positively charged. (Electrons are what puts the ‘electricity’ in static electricity.)

The extra electrons on something want to ‘jump’ over to something with fewer electrons, to sort of balance out all the electrons. So…when your hand gets near the doorknob…electrons start ‘jumping’ over the gap…and it makes a spark! Kewl, right?!? There’s a lot more to learn about static electricity, and it’s all kewl GED science….so read up at these websites:

http://www.school-for-champions.com/science/static.htm 

http://www.sciencemadesimple.com/static.html 

Next time, I’ll have a GED practice question about static electricity!! So study hard, GED-people!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.