Human being and energy
Temperature in the room at the beginning of the lesson was 20°C. Pupils learned in the classroom 45 minutes meanwhile they increased a temperature in the room by two degrees, up to 22°C. Solar energy, which warm the room thanks to windows, helped children with the increasing the temperature.
Human being maintains the temperature of 37°C. Human body is chilled by ambient environment with the lower temperature. Warmth, which radiates from the human body, is conducted to the ambient surroundings. It heats the environment by some degrees.
Children from higher year calculated, how much energy was needed for warm the room up.
They used the formula: Q = m · c (t2 – t1)
m = V · ϱ; V = 12 x 6 x 4 – volume of the room
ϱ = 1, 29 kg/ m3 – air density; c = 1, 01 KJ/kg°C
Q = m · c (t2 – t1) Q = 371,5 · 1, 01 · 2 Q = 750, 5 KJ
For the warm the room up from 20°C to 22°C was necessary to produce 750,5 KJ energy.