Monday, November 3, 2008
You gotta be brave to do this one! (Matches in a Classroom?) But it's worth it!
The best way I know how to do this lab: Demonstrate the activity.
But how do you demonstreate without spoiling the fun?
The main principle of this activity: Everyone does this together .
(1) Pass out the equipment to each small group. Warn them NOT to do anything without your direction! (If anyone does, tell them you're sorry they jumped the gun and to step out in the hall.)
(2) Ask each small group to pick the most responsible person in the group who can light the matches. Have them raise their hands. If you don't approve, reassign in any group that needs it.
(3) Talk about open flame safety for a minute. Impress on them that it's important to be safe, etc.
(4) Put a dash of cold water in the water bottle. This can be done with a beaker for each group in the tray of equipment you handed out. (You might have popped an ice cube in each one.)
(5) Watch while everyone does this.
(6) Have every group have one group member shake the bottle vigorously for about 5 seconds.
(7) Then someone squeezes the bottle in each group. What happens? (Nothing) Why? (They won't have a clue but ask them to try to put something down.)
(8) Now the fun stuff: The responsible person lights the match. Some one else unscrews the cap. The lighter drops the match in the bottle. The other person quickly recaps the bottle.
(9) The bottle gets shaken again.
(10) The bottle gets squeezed again. Squeeze. Release. Squeeze. Release. They should see it get foggy when it's squeezed. If not demonstrate with your bottle. They are looking for little cumulus clouds floating in the bottle. They are actually only going to see fog in the bottle.
(11) Have them read the explanation. Talk about CONDENSATION NUCLEI.
(12) You can have them do the hot water if you want. Not really necessary.
(13) Not hardly worth taking points for this activity. Might be a good time to roll into a Clouds PPT with FollowSheet (coming soon).
(14) Give them time to redo the experiment a couple times. It's FUN!!
NOTE: Always a good idea to do this activity yourself several times so you know what to expect. That way you'll know how much water to tell them to put in the bottle. It's different for different-sized bottles. Also the match can burn a hole in the bottom of the bottle.)
CONSIDER THIS: Make Clouds in your Classroom!
FUN LINK: Click here for the Cloud in a Bottle Activity.
Click here for Cloud Types Word Search.