edHelper.com Matter

Diffusion

---

Diffusion
Reading Level

	edHelper's suggested reading level:	grades 5 to 7
	Flesch-Kincaid grade level:	7.39

Vocabulary

	challenging words:		happening, passive, nitrogen, excess, membrane, dioxide, colored, diffuse, carbon, conserve, substance, homeland, uphill, throughout, dissolve, downhill
	content words:		Kinetic Theory

---

Print Diffusion
edHelper.com subscriber options:

	Print Diffusion  (font options, pick words for additional puzzles, and more)
	Quickly print reading comprehension
	Print a proofreading activity

---

Feedback on Diffusion

Leave your feedback on Diffusion  (use this link if you found an error in the story)

---

Diffusion By Cindy Grigg

---

¹     Why do we smell bread baking throughout the house? The answer is diffusion. A good way to describe diffusion is the moving of molecules from a place where they are concentrated close together to a place where they are less concentrated or farther apart. When molecules are spread out evenly, diffusion seems to stop.
 
²     Smells travel in the air by diffusion. Because molecules are always moving, some molecules leave the bread as it is baking. They are vented with the excess heat from the oven. These tiny molecules of bread travel through the air throughout the house to our noses.
 
³     Have you ever passed by a bakery and noticed the delicious smells down the street from it? If the wind is blowing, there will be more mixing of the molecules in the air. That can either make the smell reach you sooner, or it can spread the molecules out so that you don't notice the smell as much. Since our brains are used to the smell of air, we don't smell the oxygen, nitrogen, or carbon dioxide. Instead, we smell the other molecules mixed with our air. This is why we smell the bread baking, smoke, perfume, or other smells.

Paragraphs 4 to 9:
For the complete story with questions: click here for printable


Copyright © 2008 edHelper