P2-Heat transfers

Question 1

What do you measure specific heat capacity in?

Answer 1

J/kg*C

Question 2

What is theta?

Answer 2

The change in temperature

Question 3

When a substance is heated, it’s temp rise depends on…

Answer 3

-The amount of energy supplied to it
-the mass of the substance
-what the substance is.

Question 4

What colour will reflect radiation

Answer 4

White or shiny surfaces

Question 5

What is the def of conduction

Answer 5

A form of heat transfer , where thermal energy is transferred from one place to another.

Question 6

Give and example of a substance with a high thermal conductivity.

Answer 6

Copper

Question 7

Give and example of a substance with a low thermal conductivity

Answer 7

Plastic, rubber, wood, wool

Question 8

What is specific heat capacity

Answer 8

The specific heat capacity of the substance is the energy needs to raise the temperature of 1 kg of the substance by 1°.

Question 9

how does insulation work?

Answer 9

• it traps air particles and limits convection

-air pockets with gas particles-> no conduction

• material itself has a low thermal conductivity

Question 10

what equipment do you need to work out the specific heat capacity of aluminium?

Answer 10

power pack, joule meter, wires, thermometer, heater, insulating sleeve, aluminium.

Question 11

what safety steps should you take when doing the method for specific heat capacity?

Answer 11

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.

Question 12

which of these needs matter to travel:
-infrared radiation
-conduction
-convection

Answer 12

conduction and convention

Question 13

what are dark surfaces like with infrared radiation?

Answer 13

they are good emitters and absorbers

Question 14

what are shiny surfaces like with infrared radiation?

Answer 14

they are bad emmitters and reflect

Question 15

do a risk assessment for the insulation practical.

Answer 15

boiling water| could cut |handle boiling water
carefully + stand up
————————————————————————
Glass |break and cut| handle glass carefully
and keep in middle of
table

Question 16

what equipment do you need for the insulation practical?

Answer 16

-kettle
-water 400ml
-beaker x4
-insulators x6
-timer x4
-thermometer x4
-cardboard lid x4
-elastic band x3

Question 17

what is the method for the insulation practical?

Answer 17

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.

Question 18

what is a conclusion?

Answer 18

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.

Question 19

what is an evaluation?

Answer 19

Evaluating involves assessing how you feel it went and what could have been improved if it was to be carried out again.

Question 20

evaluate the insulation practical?

Answer 20

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.

Question 21

write a conclusion for the insulation practical.

Answer 21

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.