Diffusion

OBJECTIVE: SWBAT compare and contrast diffusion in a liquid and in a gas.


REFERENCE: http://www.biologylessons.sdsu.edu/classes/lab1/lab1.html


MATERIALS: Map of the the classroom. Grid paper. 1 beaker of water for each group. 1 drop of food coloring for each beaker. Strong smelling substance such as perfume.

VOCABULARY: Diffusion:

OPENING:

CHALLENGE: Observe a drop of dye diffuse in a beaker of water. Record your observations usng words and drawings.

MINILESSON:

1. Have students share their observations.
2. Display the Word Diffusion and its Definition.
3. Say: You observed one liquid diffusing through another liquid. You were able to see the dye move through the water. One gas can also diffuse through another gas, but if both gases are transparent, then you can't see it happening. How can we observe and record a process that we cannot see?
4. Say: I am going to open a bottle of perfume. The perfume molecules will slowly move through the room. You won't be able to see them, but you will be able to smell them. We are going to record the movement of the molcules on a map of the class. We will write down the time at which I open the bottle, and then you record the time at which the smell reaches your location.
5. Hand out the map of the classroom with grid lines. Display a large map of the classroom with grid lines. Have students find their place on the map.


WORK PERIOD

Students write the time they smell the perfume on their map. And then come to the front of the class and write on the time they sensed the perfume on the large map at the front of the classroom.

SHARE

Students record the times at which other students sensed the perfume and draw isolines connecting similar times.