The Bronze Age began about 5000 years ago - Leaving Cert Physics - Question 11 - 2022

Specific heat capacity refers to the amount of energy needed to raise the temperature of 1 kilogram of a material by 1 Kelvin (K). It is a property that varies between different materials.

To calculate the highest temperature reached by the water, we use the formula:

$Q = mc heta$

Where:

• $m = 750$ kg (since 1 litre of water = 1 kg)
• $c = 8.5$ kJ K⁻¹ (for one stone) and $50$ stones contribute $50 imes 8.5$ kJ K⁻¹ total.
• $heta$ is the change in temperature, calculated as: $heta = T_{final} - T_{initial}$

Let $T_{final}$ be the final temperature. Substituting in values:

$750 imes 4 = 50 imes 8.5 imes (T_{final} - 280)$

Solving for $T_{final}$, we find: $T_{final} = 36.95 °C$.

One way to improve the design of the fulacht fiadh for greater efficiency is to place a lid over the water. This would reduce heat loss through evaporation and maintain a higher water temperature, allowing for more effective heating.