Physics 11 Advanced Mr. Jean April 25 th, 2012. The plan: Video clip of the day Rube Goldberg Reminder Grade 10 Science Review Investigation 6A Kinetic.

Physics 11 Advanced

Mr. Jean

April 25th, 2012

The plan:

• Video clip of the day

• Rube Goldberg Reminder

• Grade 10 Science Review

• Investigation 6A

• Kinetic Energy Review sheet

Do not forget!

• Rube Goldberg Project – Approximately 10% of grade.

• Science Fair Project– Approximately 10% of grade.

RGB: Real meets digital.

Review from Grade 10:

Thermal Energy Formula:

• Q = mc∆T

• Q = Amount of thermal energy (J)• m = mass in grams (g)• c = Specific heat capacity (J / g)• T = Temperature change (ºC)

James Joule, 1818-1889

Image credit: Wikipedia

Temperature Scales:

• What is a thermometer?

• Thermometers measure temperature. The first known accurate thermometer was invented about 350 years ago.

Triple Boiling Point of water

• The point of thermal dynamics (Study of “heat” energy) is really to do work. We know that heat is really a form of motion in particles and this motion can be used to produce energy.

Heat Engine Concept

• Any time a temperature difference exists between two bodies, there is a potential for heat flow

• Examples:– heat flows out of a hot pot of soup– heat flows into a cold drink– heat flows from the hot sand into your feet

• Rate of heat flow depends on nature of contact and thermal conductivity of materials

• If we’re clever, we can channel some of this flow of energy into mechanical work

Heat Work

• We can see examples of heat energy producing other types of energy– Air over a hot car roof is lofted, gaining kinetic energy– That same air also gains gravitational potential energy– All of our wind is driven by temperature differences– We already know about radiative heat energy transfer– Our electricity generation thrives on temperature

differences: no steam would circulate if everything was at the same temperature

How much work can be extracted from heat?

Th

Qh

Qc

W = Qh – Qc

Tc

Hot source of energy

Cold sink of energy

heat energy delivered from source

heat energy delivered to sink

externally delivered work:

efficiency = =W work doneQh heat supplied

conservation of energy

Q

Let’s crank up the efficiency

Th

Qh

Qc

W = Qh – Qc

Tc

efficiency = =W work doneQh heat supplied

Let’s extract a lot ofwork, and deliver very little heat to the sink

In fact, let’s demand 100%efficiency by sending no heatto the sink: all convertedto useful work

Heat Energy:

• Julius Sumner Miller– Part #1 & #2

Investigation 6A

• Complete the tables

• Complete the graphs

• Groups who did not finish all observations you must complete them in the next 30 minutes.

What to do:

• 1) Complete Spring constant lab

• 2) Complete Kinetic Review Sheet

• 3) Complete Work & energy Problem

• 4) Work on Rube Goldberg

• 5) Work on Science Fair

What is to be passed in:

• 1) Completed tables for three different springs

• 2) Analyze and Conclude questions 1 and 2 for each spring– Be sure to have:

• All labels• Accurate measurements, units and labelling • Very readable graphs!

To do:

• 1) Complete Spring Lab – Pass in quality for Tomorrow period #2. – No title page required.

• 2) Questions on Kinetic Energy worksheet – Due Thursday morning.