## Thursday, March 31, 2011

### Solutions to Packet 9 posted

I just posted the solutions to Packet 9 here:

"Physics - Packet 09 - Solids-Liquids-Gases - Answers.pdf"

Remember, quiz on this tomorrow, Friday, April 1st.

## Wednesday, March 30, 2011

### Buoyancy Lab

Buoyancy Lab

1. Go to:
Click “Run Now!”

Learning Goals:

• Determine what factors make a hot air balloon or a helium balloon float.

Student Instructions: Follow the instructions and  ANSWER THESE QUESTIONS IN A WORD DOCUMENT AND EMAIL IT TO ME. dandrade@bridgeportedu.net

1. Why does a hot air balloon float even though it is so heavy?

2. What makes balloons float when they are full of air but not float when they are
deflated?

3. Starting with a hot air balloon, figure out how to make the balloon float. What
factors affect the balloon floating or sinking? Explain three of these factors and your
understanding of why this works as it does.

4. Move to the rigid hollow sphere. What does it mean that the sphere is “rigid?”

5. Play with the parameters of the simulation and get the sphere to float. How is the
sphere floating similar to and different from the floating hot air balloon?

6. How will you get the helium balloon to float? Explain how you plan to set all the
parameters to get the balloon floating.

7. Set the parameters as you predicted above. Did it work? If so explain why this worked.
If not explain why your predictions didn’t work and what you did to change it.

8. Summarize your findings, how does a hot air balloon that is so heavy float in air?

### Fluids and Heat Labs for class today

Fluids & Heat
Experiment 20 Density
Experiment 23 Pressure in Liquids
Experiment 24 Buoyant Force
Experiment 25 Ideal Gas Law

Instructions and what to hand in - put it all in a Word document with names and email to me. dandrade@bridgeportedu.net

Lab 20 Density
three objects on bottom (blue triangle, red/black square, red oval) - calculate density for each
list which object(s) floated (try all of the objects)

Lab 23 Pressure in Liquids
raise and lower manometer (red box with tube) and record depth and hydrostatic pressure
do for all five liquids (water, ethanol, benzol, tetrochloromethane, and mecury)
write down your observations of differences or similarities of the pressures at different depths

Lab 24 Buoyant Force
lower the mass into the liquid and note the buoyant force as it is lowered into the liquid. Note how it changes until fully submerged.
change the preselected values of base area, height and densities (do at least 6 trials)
write down your observations of the different buoyant forces vs. the area, height and density

Lab 25 Ideal Gas Law
try it out and explore concepts

Go to: http://www.physicslessons.com/qphysics.htm#qpf and answer the three questions

## Tuesday, March 29, 2011

### QUIZ FRIDAY!

On Friday, April 1st, all physics classes (periods 2,3,5,6,7) will take a quiz on Packet 9 - Density, Solids, Liquids, Gases.

There are 5 problems on the quiz. You should review the packet and your notes.

Reminder: the class notes are here:
"Physics - Density-Solids-Liquids-Gasses - part one.pdf"
"Physics - Liquids lecture notes.pdf"
"Physics - Gases lecture notes.pdf"

There is also a copy of the packet on the same site.

I will post all of the solutions to the problems on Thursday evening in case you missed any.

## Monday, March 28, 2011

### Schedule update and homework

Monday, March 28th 2011

Periods 3, 5, 6 and 7 - we did the gases lecture (notes are here: https://sites.google.com/site/dandradeedusite/Home/physics-class-files ) "Physics - Gases lecture notes.pdf"

Homework is to finish packet 9 (#18-21) - copy of packet is available here:

Period 2 - we will do the gases lecture on Tuesday and you will have the same homework listed a

## Thursday, March 24, 2011

### Schedule update and homework

Thursday, March 24th
Period 3, 5 and 7 - Liquids lecture.
Homework is Packet 9, #10-17

Lecture notes (Physics - Liquids lecture notes.pdf) and Homework packet (Physics - Packet 09 - Solids-Liquids-Gases.pdf) are posted here:

Friday, March 25th
Periods 2 and 6 will do the liquids lecture and have the same homework as noted above.

Go to this site: