September 29, 2010 - Experiment 2C

Today we did our first experiment of the year.  Yay ^_^.  It was about chemical and physical changes.

What we did was we would mix 2 out of the 4 different solutions together to create 6 different combinations.  We did this on a glass square with a 3 by 4 grid which aided in the creation of the 6 combinations.  We then recorded all the data that we had observed and then cleaned up.

	A	B	C	D
A
B
C
D

Table looked like this ^^

a video on an experiment about chemical and physical changes (click here)
                              

September, 28 2010 - Matter

On September, 28 2010 we reviewed on the things that we had learned in the past about matter. We took some notes on what matter is to help use remember the specific definition of matter.  




 Here is a link to check out this video.

http://www.youtube.com/watch?v=-Ypwtjp0FSE




Matter is divided into two categories. One is pure substances and the other is mixtures.

Pure substances 

• have one set of properties
• have only one kind of particle

Pure substances are spit into two parts. Pure substances are either Elements or Compounds.

Elements:

• are the simplest form (It cannot be decompose)
• are made of atoms

Compounds:

• are made of elements
• are chemically combined
• are the smallest particles
• are molecules (either inonic or covalent)

Mixtures

• have more than one set of properties and substances
• are physically combined

Mixtures are split into two categories as Homogeneous and Hetrogeneous.

Homogeneous:

• are uniformed throughout
• appears to have only one compound. Ex. solution.

Hetrogeneous:

• not uniform
• appears to have mroe than one component. Ex. Water and oil. Salade dressing.

         The properties of matter have physical and chemical changes as the environment around the matter changes. Physical changes are changes that you can see with the naked eye while chemical changes may not necessarily be visible. In physical changes, no new substance is formed. The chemical composition does not change. Matters that undergoes physical changes can be reversible. For example, melting point and boiling point. On the other hand during a chemical change, new substances are produced. Unlike physical changes, the changes that occur in chemcial changes are irreversible. For example, you cannot uncook a food that was already cooked.

September, 23 2010 - Unit Conversion

On September, 23 2010 we reviewed and went further on unit conversion.
We did a lot of review sheets and went over them.

Converting units might be confusing and hard to deal with. There is one way how I remember it.
starting from small it goes k<M<G<T<P. KMGTP.
There's the da, deca for decades.

Say you have to convert 20km to dm.

The equation would be 20km*(10, 000dm/1km) .
The km will get canceled and u will be left with dm.
I always put the unit ur converting from which is km on the bottom first  and then think how many dm there is in a km.  1km = 1000m 1dm = 0.1m which is 10dm = 1m then 1km = 10, 000dm and then just times that by 20.
Here's a chart for you to look at.

And here's a video for you to look at as well.

http://www.youtube.com/watch?v=w0nqd_HXHPQ

Sept 21 2010 - Scientific Notation

Scientific Notation is used to express very large or very small numbers using powers of 10.  Scientific notation is very useful and is often favored by scientists, mathematicians and engineers, who work with large numbers.
  

a ×  10^b

b is the exponent
a is the coefficient






<sup>Ex.
Change the following number into 
scientific notation : 642 000


Step one : put a decimal point into the number so that there is one digit left of the decimal point.

                  6.42000


Step two: count the number of spaces needed to get back to the origonal
                  number. Since you have to move the decimal point 5 spaces to
                  the right, the exponent is 5.


                  6.42000
                     ------> 5 spaces 
                                       
                  6.42000 X 10^5

**When moving the decimal to the right to get back to the original number, the exponent will always be 
positive.  When moving the decimal to the left to get back to the original number, the exponent will always be
negative**</sup>