1. 9/20 Mothball Phase Change Lab
Read through the powerpoint and then fill out the survey on the blog

2. We’ll be observing the physical property of the mothball changing states of matter (phase changes)
You’ll have people
observing what the mothball looks like as it changes
Observe the temp as it changes
Checking the time
Recording data

3. 2. Decide Duties on Friday
scribe/writer/timer: records main points of lab
Has good handwriting
data recorder: records data on data table
data looker: reading the temperature
hands/eyes: observe phase changes & moves apparatus *thermometer
3. In lab notebook  you’ll write down everyone’s name and their duty

4. 4. All discuss & complete pre-lab in class
4. All discuss & complete pre-lab in class. We want to see how a mothball (it looks like a gobbstopper but don’t eat it) can change from being a solid  liquid  gas then back to a liquid  solid

5. This is what you’ll be using
Mothball
Test tube
Thermometer (not for stirring)
Ring stand
Heat stand
Beaker
Water
Stopwatch (on phone or one of mine)
Alcohol burner
goggles

6. Procedures (don’t write)
Set up apparatus
Read initial temp on thermometer
Record temp and
phase on data table
4. Observe Solid,
Liquid,Gas
4. Start timer

7. Scribe: Will call out time/record every 30 sec
Everyone repeats observes/records every 30 sec
Keep heating until the mothball is boiling or temp is more than 130 C
If the temperature (red line on thermometer) gets above PULL IT OUT OF THE TEST TUBE or else you will break it

8. When mothball is completely melted and temp reaches 130 C…
Hands/Eyes –
Move burner away from the test tube
Blow out burner
Move ring stand/test tube up
Place beaker under test tube
Lower test tube into the beaker

9. Keep recording data until mothball is completely frozen
Keep recording data until mothball is completely frozen. Keep taking temperature
**Don’t stir with the thermometer  it’ll break
Record until temperature stays the same for 2 minutes

10. Data Table (on graph paper or notebook) 18 rows
Time
Temperature ( C)
Observations (Solid, Liquid, Gas…)
:30
1 min
1:30 2
2:30 3
3:30 4
4:40 5
5:30 6
6:30 7
7:30 8

11. All graph – line graph T E M P E R A T U R E C 140 130 120 110 100 9080 70 60 50 40 30 20 10 1
1:30 2
2:30 3
3:30 4
4:30 5
5:30 6
6:30 7
7:30 8
Time

12. We’ll discuss, Scribe writes -
Dependent/Responding Variable: ________
Independent/Manipulated Variable:_______

13. All write Conclusion: What did you observe?
Further Questions/what would you change?:
Now go fill out the survey on my blog saying you read through the powerpoint