The graph shows how the temperature and state of water change as the water is heated up - Leaving Cert Physics - Question 8 - 2022

At part Y, the graph indicates a change of state. The temperature remains constant as heat is added, signifying that the water is undergoing a phase change from liquid to gas (vaporization).

Energy can be supplied to the water through various methods:

• Using a joule meter to measure electrical energy supplied.
• Using elemental heating such as placing the water container on a hot plate or heating element to transfer thermal energy directly.
• Electricity could flow through a coil submerged in the water to heat it.
• Another method is to place the water container under a high-temperature source where heat radiates towards it.

To calculate the energy required, we use the formula: $Q = m imes L$ where:

• $Q$ is the energy required,
• $m$ is the mass (0.2 kg), and
• $L$ is the latent heat of fusion (330000 J/kg). Thus, substituting the values: $Q = 0.2 imes 330000 = 66000 ext{ J}$

A steam burn is more dangerous because steam contains more energy than boiling water at the same temperature. When steam condenses on skin, it releases this additional heat energy, causing more severe burns compared to boiling water which primarily involves the transfer of thermal energy.

A thermometric property is a physical property that changes predictably with temperature. It allows for temperature measurement, typically one that changes measurably with heat or temperature variation.

1. Volume of liquid in a thermometer (e.g., mercury) expands with increased temperature.
2. Resistance of a metal wire changes with temperature in a thermistor.

To calibrate a thermometer, the following steps can be followed:

1. Prepare a calibrating bath containing ice and water at 0 °C.
2. Immerse the thermometer in the mixture until stable readings are achieved.
3. Note the reading on the thermometer and mark it as the zero point.
4. For higher temperatures, employ a boiling water bath at 100 °C and follow similar steps to calibrate the upper range.
5. A labelled diagram should illustrate the setup including a thermometer, ice-water bath, and boiling water bath.