I need to come up with an idea for a good Physics experiment for my IB Physics class. Any ideas on what I can do?

OK.  During my exhaustive 5-seconds of online research, I found
one place that says that 1 BTU is about 0.293071 watt-hour.  That
should be enough to get me going.

(12 x 10^6 BTU / 30 days) x (day/24 hour) x (0.293071 watt-hour/BTU) =

(12 x 10^6) x (0.293071)  /  (30 x 24)  watts  =  4,884.5 watts .


As a check, I grabbed another conversion off the web, and I'll do
the whole thing again with that one.  Let's see if I come anywhere
close to my first answer this time:

This one says that  12,000 BTU = 3.51685 kWh .
So ...

(12 x10^6 BTU) x (3.51685 kW-hr / 12,000BTU) x (day/24 hr) / (30 day) =
 
 (12 x 10^6) x (3.51685)  /  (12,000 x 24 x 30)  kW   = 4.8845 kW

Couldn't ask for any nicer agreement !
That's my answer and I'm sticking to it.