Applying the Old to the New

Hopefully many of you (students and parents) are visiting the site for the first time today, if so great! Welcome to My Science Space, take a good look around and leave me a comment.

Speaking of comments, I just read a new comment left tonight on an old post from April. When you post a comment it is emailed to my home email account and I read and approve it before it actually shows up on the site (called moderation). In fact I read more than just your comment I go back and read the original post and all the other comments. This post was about grades but in the comments a student asked about independent and dependent variables in a lab we were doing.

Can you determine the independent and dependent variables in the interactions between spheres we've discussed in class? Here's the comment and my response in the post from April, see if it helps.

Comments:

Anonymous said...

Mr. Grant i was working on the mentos lab and i ran into a problem. I think the dependent variable is the types of soda in liters. And i thing the Independent variable is the mentos in meters due to the information my partner gave me.
4/26/2007 6:05 PM
Mr. Grant said...

Let's go back to some basics:

Question: What's a variable?

Answer: A variable is an object, event, idea, feeling, time period, or any other type of category you are trying to measure. There are two types of variables-independent and dependent.

Question: What's an independent variable?

Answer: An independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure. For example, someone's age might be an independent variable. Other factors (such as what they eat, how much they go to school, how much television they watch) aren't going to change a person's age. In fact, when you are looking for some kind of relationship between variables you are trying to see if the independent variable causes some kind of change in the other variables, or dependent variables.

Question: What's a dependent variable?

Answer: Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it. Usually when you are looking for a relationship between two things you are trying to find out what makes the dependent variable change the way it does.

Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in they way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:

(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).

For example:

(Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying).

We see that "Time Spent Studying" must be the independent variable and "Test Score" must be the dependent variable because the sentence doesn't make sense the other way around.

Now try this with your independent and dependent variables.
4/26/2007 7:46 PM

More About Earth's Spheres

Earth's Spheres
Everything in Earth's system can be placed into one of four major subsystems: land, water, living things, or air. These four subsystems are called “spheres.” Specifically, they are the geosphere (land), hydrosphere (water), biosphere (living things), and atmosphere (air). Each of these four spheres can be further divided into sub-spheres. To keep things simple in this course, there will be no distinction among the sub-spheres of any of the four major spheres.

Goeosphere
The geosphere (also often referred to as the lithosphere*) contains all of the cold, hard solid land of the planet's crust (surface), the semi-solid land underneath the crust, and the liquid land near the center of the planet. The surface of the geosphere is very uneven (see image on right). There are high mountain ranges like the Rockies and Andes (shown in red), huge plains or flat areas like those in Texas, Iowa, and Brazil (shown in green), and deep valleys along the ocean floor (shown in blue).

The solid, semi-solid, and liquid land of the geosphere form layers that are physically and chemically different. If someone were to cut through Earth to its center, these layers would be revealed like the layers of an onion (see right image above). The outermost layer of the geosphere consists of loose soil rich in nutrients, oxygen, and silicon. Beneath that layer lies a very thin, solid crust of oxygen and silicon. Next is a thick, semi-solid mantle of oxygen, silicon, iron, and magnesium. Below that is a liquid outer core of nickel and iron. At the center of Earth is a solid inner core of nickel and iron.

* Note: The word "lithosphere" can take on different meanings depending on the speaker and the audience. For example, many geologists--scientists who study the geologic formations of Earth--reserve the word "lithosphere" to mean only the cold, hard surface of Earth, and the upper portion of the mantle, not the entire inside of the planet. I will try to be consistent and use the more inclusive term "geosphere". However, there will be times when I use other sites or information from other authors who will use the term "lithosphere" as I do geosphere.

Hydrosphere
The hydrosphere contains all the solid, liquid, and gaseous water of the planet.** It ranges from 10 to 20 kilometers in thickness. The hydrosphere extends from Earth's surface downward several kilometers into the geosphere and upward about 12 kilometers into the atmosphere.

A small portion of the water in the hydrosphere is fresh (non-salty). This water flows as precipitation from the atmosphere down to Earth's surface, as rivers and streams along Earth's surface, and as groundwater beneath Earth's surface. Most of Earth's fresh water, however, is frozen.

Ninety-seven percent of Earth's water is salty. The salty water collects in deep valleys along Earth's surface. These large collections of salty water are referred to as oceans. The image above depicts the different temperatures one would find on oceans' surfaces. Water near the poles is very cold (shown in dark purple), while water near the equator is very warm (shown in light blue). The differences in temperature cause water to change physical states. Extremely low temperatures like those found at the poles cause water to freeze into a solid such as a polar icecap, a glacier, or an iceberg. Extremely high temperatures like those found at the equator cause water to evaporate into a gas.

** Note: Some scientists place frozen water--snow, glaciers, icecaps, and icebergs--in its own sphere called the "cryosphere." In our class, however, frozen water will be included as part of the hydrosphere. The word "hydrosphere" will be used in reference to all water in Earth's system.

Biosphere
The biosphere contains all the planet's living things. This sphere includes all of the microorganisms, plants, and animals of Earth.***

Within the biosphere, living things form ecological communities based on the physical surroundings of an area. These communities are referred to as biomes. Deserts, grasslands, and tropical rainforests are three of the many types of biomes that exist within the biosphere.

It is impossible to detect from space each individual organism within the biosphere. However, biomes can be seen from space. For example, the image above distinguishes between lands covered with plants (shown in shades of green) and those that are not (shown in brown).

***Note: Some scientists place humans in their own sphere called the "anthrosphere". In our class, however, humans will be included as part of the biosphere. The word "biosphere" will be used in reference to all living things in Earth's system.

Atmosphere
The atmosphere contains all the air in Earth's system.**** It extends from less than 1 m below the planet's surface to more than 10,000 km above the planet's surface. The upper portion of the atmosphere protects the organisms of the biosphere from the sun's ultraviolet radiation. It also traps heat. When air temperature in the lower portion of this sphere changes, weather occurs. As air in the lower atmosphere is heated or cooled, it moves around the planet. The result can be as simple as a breeze or as complex as a tornado.

****Note: The atmosphere is made up of many layers that differ in chemical composition and temperature. The word "atmosphere" will be used in reference to all of the layers.

Earth's Spheres

I just love this illustration we used in class today. To me it captures both the simplicity of Earth's spheres (land, water, air and life) and the complexity of their make-up and interactions. I hope you view your Earth with a bit of amazement, wonder and curiosity.

Enjoy your year of discovery.

El Nino

I was looking around for more information about El Nino and I found this clip on a NASA site. Click on the image to see the movie (requires QuickTime and speakers).

Here's the site I found it on. It provides some good basic information about El Nino. Follow this link : http://kids.earth.nasa.gov/archive/nino/intro.html or click on the image below.

Welcome to a New Year of Science

Hey, I'm glad you stopped by the site. I'm still making some changes to it, but by the end of the week, I should have it all done. Take some time and look around.

This year we'll be studying Earth and Space Science and in fact although today is just the second day of class, we already started by viewing the video on tropical storms. Now even though I didn't require you to take notes on the video, it contained some important information.

What can you tell me about the formation of hurricanes? How does El Nino affect hurricanes? What should you do to prepare for hurricanes? If you find it difficult to answer these questions then consider it a gentle suggestion to pay a little more attention in class. Perhaps, even when it's not required, you might still take notes.

One of the things I like to do on the site is give you additional sources for information and study. Remember I said learning is your responsibility and every night you should be at least reviewing what we did in class or going a little deeper. Well click on this link and check out some of the sources from WFTV.