Sloth Sanctuary

Everyone knows I support the Child's Play charity, but I do contribute to others as well. If you are looking to do some good and help out a group that gets little notice but does fantastic work, check out the Sloth Sanctuary in Costa Rica. A little bit goes a long way there and if you can skip a couple of lattes one week, you might consider sending them the savings. They are having a year-end drive that ends on Jan. 1 that could use some propping up:



and you can send them some scratch through Razoo (very nice online fundraising service) by clicking on the image. If you're like me and prefer to help out those that a trillion people aren't giving to already, consider the Sloth Sanctuary. You can give anytime by visiting their site and making a direct donation to this great group.

Hope the break is going well - see you soon!

And Off We Go...

Today was a day of finishing tests and snatching up some bonus points. What I did is put up to 5 points from your bonus work onto your last test and if you got more than 5, I dropped it onto homework. So, happy holidays from me...

When we return, be ready to launch into new material and don't lose sight of the fact that midterms start not long after we get back from break. You have your notes, tests, review sheets, homework, etc., so do not put off studying for that exam, which goes back to Day 1!

Test Day!

Oh what fun it is... everyone was engaged in their Chapter 9 exams and, hopefully, all loose ends will be securely tied off before we leave tomorrow. When we return, be prepared to hit heat and topics like heat transfer, change of phase, latent heat, specific heat and all sorts of other goodies...

Big Ol' Review Day

Tomorrow is the Chapter 9 exam for everyone and today was set aside to tie up all loose ends. We walked through the chapter page by page and addressed any issues that folks had with the material. Email me tonight (early!) or stop by tomorrow before school if you have any additional questions. When we return from break, we'll be jumping into the topics of heat and thermodynamics and that should take us right to the midterm exam!

A Bunch of Hot Air

Everyone was working on gases today, among other things and that wraps up the new information for the chapter and Wednesday's exam. B and E Blocks discussed the ideal gas law and its derivations (Boyle's, Charles's and Gay-Lussac's laws) and the homework problems tonight focus on working with the ideal gas law. I posted one video over the weekend (9.4 #4) and here's another to help you work through some of the ideas:

9E #3



C Block reviewed their gas law homework, then began a practice test that we will use as part of our exam review tomorrow. F Block went over the same homework, but then moved to the buoyant forces lab that allowed them to see the variation in pressure with depth in a column of fluid and work with the pressure-with-depth formula (which was a special case of Bernoulli's equation for static fluids). We'll go over the lab in class tomorrow and walk through the chapter as part of our review for Wednesday's exam.

For all blocks, when we return from break, the topic of interest will be heat, so prepare for a little bit of a gear change...

Yeah!

Child's Play charity is just poised to break 2 x 10⁶ k! That's 2 million smackeroos for the exponentially challenged. I just put in my contribution of some DS games that were on Boston Children's Hospital wishlist at Amazon. Looks like lots of locals really opened their wallets this year. I looked at the wishlist early in the season and what remains is only a fraction of what was there. Glad to see that local gamers did their part to help with the cause and make some sick kids a little happier this year...

Gas Law Problems

Here's a worked out example to help with the work we'll go over tomorrow...

9.4 #4

Center of Mass

When an object's center of mass is positioned beyond the object's base of support, the object will tip. Glad to know people are out there making practical use of this principle for the benefit of mankind...

Problem-Solving Help

Here are a couple of videos for tonight's homework (for C, E and F at least)

9D #1




9D #2




9.3 #3

Good old' Bernoulli

Folks were working with Bernoulli's Principle or equation in class.  B Block springboarded from their pressure with depth lab into the ideas associated with fluids in motion.  We. looked at types of fluid flow, the ideal fluid model and then looked at how conservation of mass in moving fluids is this field by the relationship outlined by the continuity equation.  We'll go into conservation if energy in fluid systems tomorrow. with was the ground trod by C, E and F Blocks.  Those classes reviewed Bernoulli's  Principle and the continuity equation and pressed forward with Bernoulli's equation.  Bernoulli's equation is a mathematical statement that energy in a fluid system is conserved.  Energy can be bound In kinetic energy, gravitational potential energy and pressure.  The energy can be converted from one form to another any number of times and not all forms may be present at different points in the system.  We'll review all of this and the associated homework tomorrow, so do your best working with the ideas and formulas. Then, it is on to properties and behaviors of gases.

I Made a Video!

Finished watching the new Fright Night film (not bad - David Tennant rules, as usual) and tried out a new app on the iPad. Click the Play button to see what I cobbled together in an unedited round for the continuity equation. Maybe I'll try and keep up with doing some videos, especially if they actually let me make the background dark. I hate white backgrounds...

Fluids are Moving and Grooving

C, E and F Blocks began a discussion on fluids in motion. We took time to contrast laminar and turbulent flow, described the ideal fluid model, discussed conservation of mass (as satisfied by the continuity equation) and dabbled in Bernoulli's Principle. Bernoulli's Principle explains a number of phenomena in real life that we outlined in class and a few more examples will be added tomorrow. Bernoulli also provides us with Bernoulli's equation, which will demonstrate how fluid systems satisfy the Law of Conservation of Energy.

B Block conducted a lab investigation on variations in fluid pressure with depth. The linear relationship derived from the experimental data nicely corroborated the basic pressure with depth formula: P = P_o + ρgh. We took time to examine the parts of that equation as demonstrated in the investigation and will take time tomorrow to see if you were able to successfully transfer that experience into problem-solving techniques for your homework problems. Then, it's onto fluids in motion!

Catching Up

Me... not you...

With my absence yesterday, today was a day to take up the slack, tie up loose ends and cover some new ground while we were at it. B and E Blocks reviewed and spot-checked understanding for buoyancy and began a walk through the topic of pressure. We took time to define pressure, contrast it from force, discuss Pascal's Principle and its application to hydraulic devices and explain how and why pressure varies with position in a column of fluid. Tomorrow, we'll put the icing on pressure and begin to take a look a fluids in motion. Well, E Block will do this - B Block will be investigating pressure with depth and the absolute pressure formula: P = P_o + ρgh - and using that to further their discussion of fluid pressure.

C and F Blocks tidied up their work with fluid pressure. C Block conducted a lab investigation that verified the linear relationship between pressure and position in a fluid column and saw that the equation of the line for that experiment was simply the formula for absolute pressure that we worked with in class. Some additional pressure-depth practice problems were assigned for practice and all of this will be reviewed tomorrow before we move on to fluids in motion. F Block discussed the idea of pressure with depth and how that could be extended to the effects on living creatures that we observed when they are exposed to significant variations in environmental pressure. Tomorrow, we move from stationary fluids to fluids in motion and see how that motion affects fluid pressure and direction of motion.

Hipsters...

...they're everywhere...

Friday is Happy Day!

B block reviewed their rotational dynamics exams and then moved onto their buoyancy homework problems. That took a bit more time than expected and we took the safe course of working on a few more before moving on to new material. On Monday, we'll start off by looking at these additional buoyancy problems before moving onto fluid pressure.

C Block checked over their pressure problems and then took a look of how fluid pressure varied with depth in the fluid column. Atmospheric pressure is highest at ground level since all the layers of the atmosphere pushing down on your head. As you rise, there is less mass, therefore weight on you, so the pressure diminishes. The same is true when you descend in the ocean. And because objects are 3-dimensional, the pressure on the bottom of the object is larger than the pressure on top of the object, ensuring a net upwards force. There is the origin of the fluid's buoyant force... we'll go over your homework problems on Monday and then tackle the topic of fluids in motion.

E Block investigated Archimedes Principle. For a completely submerged object, the buoyant force is basically constant. But, as you progressively submerged the object, the buoyant force increased as the volume of the displaced fluid increased. Have your write-up ready for Monday, as well as your buoyancy problems to review before we move on to fluid pressure.

F Block reviewed their buoyant forces lab and the associated lab questions and then, after reviewing the buoyancy homework, moved onto fluid pressure. Fluids exert pressure on objects in them and on their containers. For a closed system, if additional pressure is added to the system, it is transmitted equally in all directions in the fluid - Pascal's Principle. We discussed how this applied to hydraulic devices and worked a few problems in class with a hydraulics device. You have a few more to work for homework and we'll go over these on Monday before moving on to looking at how fluid pressure varies with position in a fluid column.

Have a great weekend!