About
http://weelookang.blogspot.sg/2014/11/ejss-cube-block-cooling-model.html
image of
copper shiny https://c1.staticflickr.com/1/164/362133253_77585f5429_z.jpg?zz=1
copper dull https://www.colourbox.com/preview/10760507-196481-golden-copper-shiny-abstract-vertical-background.jpg
al shiny http://preview.cutcaster.com/cutcaster-photo-100709683-metal-texture.jpg
al dull http://pixabay.com/p-432524/?no_redirect
fe shiny http://www.burningwell.org/gallery2/d/11247-6/img_0571.jpg
fe dull http://upload.wikimedia.org/wikipedia/commons/1/1d/Old_dirty_dusty_rusty_scratched_metal_iron.jpg
Translations
Code | Language | Translator | Run | |
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Credits
This email address is being protected from spambots. You need JavaScript enabled to view it.; christian wolfgang
Sample Learning Goals
SLS Lesson by Kong Su Sze
Good conductors of heat
steel, copper
Poor conductors of heat
plastic, wood
Answer Key
For Teachers
Newton's Law of Cooling
The Newton's Law of Cooling model computes the temperature of an object of mass M as it is heated or cooled by the surrounding medium.
Assumption:
Validity:
Convection-cooling "Newton's law of cooling" Model:
\( T_{background} \) is the temperature of the surrounding background environment; i.e. the temperature suitably far from the surface is the time-dependent thermal gradient between environment and object.
Definition Specific Heat Capacity:
The specific heat capacity of a material on a per mass basis is\( m \) is the mass of the body
\( c \) specific heat capacity of a material
\( T_{final} \) is the \(T_{background}\)
\( T_{initial}\) is the \( T(t) \)
\( \frac{mc ( T_{background}- T(t) ) }{\delta t} = h A( T(t) - T_{background} )\)
assuming mc is constant'
\( mc \frac{ \delta ( T_{background}- T(t) ) }{\delta t} = h A( T(t) - T_{background} )\)
\( \frac{ ( T_{background}) }{\delta t} = 0 \)
negative sign can be taken out of the differential equation.
\( \frac{ ( T(t) ) }{\delta t} = -\kappa ( T(t) - T_{background} )\)
If heating is added on,
the final ODE equation looks like
Definition Equation Used:
\( V \) is volume of object
\( \rho \) is density of object
\( A \) surface area of object
assumption of increased surface are
Materials added:
copper shiny \( c_{Cu} \) = 385 \( \frac{J}{kg K}\)\( \rho_{Cu} \) = 8933 \( \frac{kg}{m^{3}}\)
heat transfer coefficient \(h_{Cu}\) = 400 \( \frac{W}{(K m^{2})} \)
copper dull \( c_{Cu} \) = 385 \( \frac{J}{kg K}\)
\( \rho_{Cu} \) = 8933 \( \frac{kg}{m^{3}}\)
heat transfer coefficient \(h_{Cu}\) = 200 \( \frac{W}{(K m^{2})} \)
aluminium shiny \( c_{Al} \) = 903 \( \frac{J}{kg K}\)
\( \rho_{Al} \) = 2702 \( \frac{kg}{m^{3}}\)
heat transfer coefficient \(h_{Al}\) = 400 \( \frac{W}{(K m^{2})} \)
aluminium dull \( c_{Al} \) = 903 \( \frac{J}{kg K}\)
\( \rho_{Al} \) = 2702 \( \frac{kg}{m^{3}}\)
heat transfer coefficient \(h_{Al}\) = 200 \( \frac{W}{(K m^{2})} \)
iron shiny \( c_{Al} \) = 447 \( \frac{J}{kg K}\)
\( \rho_{Al} \) = 7870 \( \frac{kg}{m^{3}}\)
heat transfer coefficient \(h_{Al}\) = 400 \( \frac{W}{(K m^{2})} \)
iron dull \( c_{Al} \) = 447 \( \frac{J}{kg K}\)
\( \rho_{Al} \) = 7870 \( \frac{kg}{m^{3}}\)
heat transfer coefficient \(h_{Al}\) = 200 \( \frac{W}{(K m^{2})} \)
Users can select the mass of the object and the material and the model computes the surface area assuming a cubic shape. The model plots the object's temperature as a function of time as the user heats and cools the object. A data-tool button on the temperature graph allows users fit the data to analytic functions.
Note: A typical (rough) heat transfer coefficient h for still air and iron is 6 W/(K m^2) and 400 W/(K m^2) . The Newton's Law of Cooling model assumes h=400 for all shiny and h=200 for dull materials. The actual value of h depends on many parameters including the material, the fluid velocity, the fluid viscosity and the condition of the object's surface.
References:
- "Measuring the Specific Heat of Metals by Cooling," William Dittrich, The Physics Teacher, (in press).
Credits:
- The Newton's Law of Cooling model was created by Wolfgang Christian using the Easy Java Simulations (EJS) version 4.2 authoring and modeling tool.
- EJSS Cube Block Cooling Model was created by Wolfgang Christian and recreated by lookang using the Easy Java Simulations (EJS) version 5.1 authoring and modeling tool
Research
[text]
Video
https://www.youtube.com/watch?v=8a8nTQIdLOM
Version:
- http://weelookang.blogspot.sg/2014/11/ejss-cube-block-cooling-model.html
- https://vle.learning.moe.edu.sg/community-gallery/lesson/view/5d907c47-4ae6-47e7-8cce-04199b1cd386
Hands-On Kits
- http://www.addest.com/products/category/Science_Kits by Addest Station Cooling Curve Kit
Other Resources
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- Details
- Parent Category: 13 Thermodynamic Systems
- Category: 04 Thermal Properties of Matter
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