Archive for the ‘Physics’ Category

GED Practice Question Answer: Lava Lamps

Monday, November 12th, 2007

Did you figure out the answer to this question about lava lamps?

What would happen if Dwayne (that’s me!) made a new kind of lava lamp with a light on the top as well as one on the bottom?

A) When the lamp was on, the lava stuff would move twice as fast.

B) When the lamp was on, the lava stuff wouldn’t move at all.

C) When the lamp was on, the lava stuff would go to the top and stop.

D) The lava stuff would keep moving even when the lamp was off.

E) The lamp would overheat.

The answer is… drumroll please…… C! The lava would go to the top of the lamp, then stop. How come?

Well, as we figured out, the lava rises up because the lamp at the bottom get hotter, kind of like how a hot-air balloon rises because the air is hotter, and hotter stuff is lighter.

So, if there was a lamp on both top and bottom, the stuff would still get hot, and it would rise to the top… but it wouldn’t ever cool down, because the lamp at the top would keep it hot. So it would go up to the top and stay there!

Make sense to you? Ask me if you don’t get it. And I promise, next time I’ll talk about something new! Even though lava lamps are really kewl…

GED Science… Extraterrestrialpolation

Monday, November 5th, 2007

What does extraterrestrialpolation have to do with the GED test? Yeah, I know, the real word is “extrapolation.” But I like really long words. What “extrapolation” really means is taking things you know and seeing what you can figure out from them. So you make your knowledge bigger by like, expanding it into new things. And that helps a lot with GED preparation. Cuz that’s one of the things they want you to do on the GED.

So, last time, I told you how a lava lamp works. Basically, the light at the bottom makes the waxy stuff get hot. When it’s hotter, it’s less dense than the liquid, so it floats up. When it gets to the top, it cools down, gets more dense, and sinks down… makin’ kewl psychedelic lava lamps.

Here’s the extrapolation:

What would happen if Dwayne (that’s me!) made a new kind of lava lamp with a light on the top as well as one on the bottom?

A) When the lamp was on, the lava stuff would move twice as fast.

B) When the lamp was on, the lava stuff wouldn’t move at all.

C) When the lamp was on, the lava stuff would go to the top and stop.

D) The lava stuff would keep moving even when the lamp was off.

E) The lamp would overheat.

Hehehehe… I’m turning lava lamps into GED preparation! Good luck on this one! Let me know what you think…

Psychedelic Science!

Monday, October 29th, 2007

Know what I always thought was totally enlightening? A lava lamp! Yeah, they’re so kewl. I don’t know if you’ve got one, but you turn it on and the stuff all flows all meditative like through the water… and the whole thing glows. Totally trippy!

Seems like, lava lamps is really science! Who knew? Here’s how it works. So, the lava lamp’s got two things in it, right? There’s the liquid, and then there’s the thicker stuff that goes up and down. How’s it move? It looks like magic! But it’s really science, see?

Here’s the physics: Heavy things sink, and light things float. Sounds really non-scientific, right? Cuz like a rock will sink, but a leaf will float. Science guys say, “Dense things sink, and less dense things float.” That’s cuz a really tiny rock and a really gigantic, humongous leaf might weigh the same… but the rock is smaller. It’s got more weight for its size. So it’s dense.

Anyway, heat makes things expand… they get bigger. So when the thick stuff in the lava lamp gets hot, cuz of the bulb at the bottom of the lamp heats it up, it expands. That means it’s less dense. So it goes up…. then it gets to the top, cools off, gets more dense again, and falls down. Up and down, up and down, as it gets hotter and colder. Kewl!

You can even make your own lava lamp at home. That’s one thing I like about science, is you can build things with it. Here’s a link that shows you how: http://www.oozinggoo.com/howto.html

And if you want to know some cool non-science stuff about lava lamps, here some info about the guy who invented them! He sounds like a bit of a wacko…. like me! http://inventors.about.com/library/weekly/aa092297.htm