Lab deomonstration for interactions of human systems

The purpose of this lab demonstration is to show the cell membrane function.
The materials used in this lab are dialysis tubing, cornstarch solution, iodine solution, and a beaker.
The preparation for the lab is... cut a strip of dialysis tubing (about 4 inches long).  It needs to be soaked in water for approximately one minute.  One end of the tubing needs to be tied shut.  The cornstarch solution should be added into the tubing and then tied off, so that the tubing has a fleeting resemblance to a water balloon.
The procedure demonstrates how iodine reacts with starch.  The dialysis tubing/cornstarch solution should be placed into the beaker of iodine solution.  The minimum amount of time to wait for results is 5 minutes.
If the dialysis tubing is sealed on both ends, so that none of the cornstarch solution leaks into the iodine solution, the tube of white starch solution will change to a dark purple color.
During the procedure, iodine passes through the dialysis membrane and reacts with the cornstarch.  This is called diffusion.  The cornstarch is not able to diffuse through dialysis membrane because the size of the cornstarch molecules are relatively big. This demonstrates that the cell membrane is selectively permeable because Iodine molecules can pass through the dialysis membrane, when the starch molecules cannot.

Exploratory computers

I would like you to create a formal business letter during class today.  There are certain ways you should write letters.  Each way is dependent on to whom the letter is being addressed to.  Here are directions, that I would like you to follow, on how to write a business letter. 

Here is an example of a business letter that you can also use to help you through the letter writing process.

8th grade Punnett Square practice examples

Here are 2 different places to practice Punnett Squares

Website #1
This uses Adobe Shockwave player. It has nice information that you can use to follow and use to work on the examples. The last example is pretty challenging. Can you figure it out?

Math Practice
This quiz was created by the makers of our science book. This is not as helpful as the first example, but you should already be familiar with all the information asked within the 10 problems.

Here are some practice questions for sections 1-3 along with a practice quiz and test for chapter 2.
Section 1 Quiz
Section 2 Quiz
Section 3 Quiz
Crossword Puzzle
DNA Information
Chapter Review Quiz
Ch 2 Test Practice

7th grade Chapter 2 Minerals

Minerals are the building blocks of rocks. They are non-living, solid, and, like all matter, are made of atoms of elements. There are many different types of minerals and each type is made of particular groups of atoms. The atoms are arranged in a network called a crystal lattice. The lattice of atoms is what gives a mineral its crystal shape.

Different types of minerals have different crystal shapes. Most minerals can grow into crystal shapes if they have enough space as they grow. But there are often so many different crystals growing in the same little area that they all compete for space and none of the crystals is able to grow very large.

There are two main ways that new crystals of minerals grow. Some minerals form when molten rock, called magma below a planet’s surface and lava above, cools and atoms bond together into mineral crystals. Other minerals form when water that has atoms of dissolved elements in it, evaporates away. The atoms get very close to each other and may bond together to form solid minerals.

The special shapes of minerals are not the only difference between them. Minerals can be identified by other physical properties (appearance, hardness, luster, specific gravity, streak, cleavage and fracture) as well. Each type of mineral has its own special characteristics.

Here is a nice time lapse video of crystal formation.


Here is a nice website that has a number of examples of minerals which are probably found in your home.

Here are some practice questions for sections 1-3 along with a practice quiz and test.
Section 1
Section 2
Section 3
Crossword Puzzle
Practice Quiz
Test practice

The Baking Soda/Vinegar experiment