P2-Heat transfers Flashcards
What do you measure specific heat capacity in?
J/kg*C
What is theta?
The change in temperature
When a substance is heated, it’s temp rise depends on…
-The amount of energy supplied to it
-the mass of the substance
-what the substance is.
What colour will reflect radiation
White or shiny surfaces
What is the def of conduction
A form of heat transfer , where thermal energy is transferred from one place to another.
Give and example of a substance with a high thermal conductivity.
Copper
Give and example of a substance with a low thermal conductivity
Plastic, rubber, wood, wool
What is specific heat capacity
The specific heat capacity of the substance is the energy needs to raise the temperature of 1 kg of the substance by 1°.
how does insulation work?
- it traps air particles and limits convection
-air pockets with gas particles-> no conduction
- material itself has a low thermal conductivity
what equipment do you need to work out the specific heat capacity of aluminium?
power pack, joule meter, wires, thermometer, heater, insulating sleeve, aluminium.
what safety steps should you take when doing the method for specific heat capacity?
SAFETY
- hold heater by wires so as not to burn yourself.
- place heater on heat proof mat once finished, to increase the speed of cooling.
which of these needs matter to travel:
-infrared radiation
-conduction
-convection
conduction and convention
what are dark surfaces like with infrared radiation?
they are good emitters and absorbers
what are shiny surfaces like with infrared radiation?
they are bad emmitters and reflect
do a risk assessment for the insulation practical.
boiling water| could cut |handle boiling water
carefully + stand up
————————————————————————
Glass |break and cut| handle glass carefully
and keep in middle of
table
what equipment do you need for the insulation practical?
-kettle
-water 400ml
-beaker x4
-insulators x6
-timer x4
-thermometer x4
-cardboard lid x4
-elastic band x3
what is the method for the insulation practical?
1) collect the equipment listed in the equipment list and set up as shown in the diagram.
2) boil 400ml of water in the kettle
3) carefuly pour 100ml of boiling water into one of the beakers and using a thermometer measure the temperature
4) when the water becomes 85 degrees start the timer and put the lid on the beaker.
5) note the temperature of the water in the beaker every 30 secs.
6) repeat for the other three beakers.
what is a conclusion?
A conclusion is a statement based on the experiment and your observations. It includes a summary of the results, whether or not the hypothesis was supported and the significance of the experiment.
what is an evaluation?
Evaluating involves assessing how you feel it went and what could have been improved if it was to be carried out again.
evaluate the insulation practical?
To evaluate, we could have repeated the experiment multiple times to acquire more accurate results. Also, some of the cardboard lids were inconsistent in size therefore there were gaps in some, allowing convection to occur. Furthermore, another thing we could have improved was that we did not use insulation on the bottom of the beaker meaning that heat could disperse out the bottom through conduction.
write a conclusion for the insulation practical.
To conclude, it is evident that the more inslation used the higher the temperature and average and the slower the temperature decrease. This is because insulation has a low thermal conductivity. we can see this as the beaker with no insulation’s temperature dropped faster than the other ones with it.
