Vehicle battery as a power source

[Drummo1995]

If I use a vehicle battery connected to jumper cables, which is then connected to the heating element of a kettle, which is then placed in play sand, in a metal container, will the sand then heat up?

 

[James]

yes.
assuming it is a normal uk kettle it is normally 2 to 3kw at 230v
assuming it is 3kw
3000 / 230 x 12 =150watts

so it would warm the sand but not very quickly as it will only give out 1/20th of its normal power output as it is being run at 1/20th of its normal voltage.

 

[Avo Mk8]

yes.
assuming it is a normal uk kettle it is normally 2 to 3kw at 230v
assuming it is 3kw
3000 / 230 x 12 =150watts

so it would warm the sand but not very quickly as it will only give out 1/20th of its normal power output as it is being run at 1/20th of its normal voltage.

I was thinking 150W is still a lump of power
Using online calculator Watts to Heat Calculator - https://www.omnicalculator.com/physics/watts-to-heat

To heat 1Kg of sand by 10 DegC with 150W will take just under 1 minute (still sounds unlikely - mistake?)
I suspect the thermal conductivity of sand is not great, so it might ultimately get quite hot.
Whereas 1Kg (1L) of water with the same 150W would take nearly 5 minutes to rise 10 DegC!

I hope the mention of 'play sand' doesn't suggest it might be played with, as I suspect this could ultimately get dangerously hot in the vicinity of the element?

 

[James]

I was thinking 150W is still a lump of power
Using online calculator Watts to Heat Calculator - https://www.omnicalculator.com/physics/watts-to-heat

To heat 1Kg of sand by 10 DegC with 150W will take just under 1 minute (still sounds unlikely - mistake?)
I suspect the thermal conductivity of sand is not great, so it might ultimately get quite hot.
Whereas 1Kg (1L) of water with the same 150W would take nearly 5 minutes to rise 10 DegC!

I hope the mention of 'play sand' doesn't suggest it might be played with, as I suspect this could ultimately get dangerously hot in the vicinity of the element?

I don't think it is a mistake, would not be surprised if sand has a specific heat capacity of 0.2 x that of water.

 

[littlespark]

I don’t think the cup of tea is going to taste very nice….. and maybe a bit cold