 Today, we are going to understand some basics about latent heat by performing a small experiment using Dabel's IoT module that locks real-time value of temperature in the data logger in the module. Before we start, let's briefly understand what latent heat is. Latent heat is the thermal energy that is absorbed or released by a substance during its phase change without any change in the temperature. How does the temperature remain constant and where does the heat go? Let's find out. For that, we need a kettle, a DS18V20 waterproof temperature sensor, a vibe, a smartphone with Dabel installed, and some ice. Let's start by making the connections. Connect the 4.7 kilo ohm resistor and connect one of its terminals to the VCC pin. Connect the second terminal to AYS pin number 5. Take the temperature sensor and connect its signal pin to the resistor terminal connected to pin number 5. Connect the VCC and ground pins of the temperature sensor to AYS VCC and ground pins respectively. Connect the HC05 Bluetooth module. Once you are done with the connections, write the code and upload it to a vif. Now let's set up the experiment. Place the ice inside the kettle, then place the temperature sensor. Open Dabel in your smartphone and pair it with a vif. Open the IoT module and select the data logger. The temperature of the kettle with the ice is displayed on the vif's TFT screen. The data logger continues the records to temperature during the experiment. After all the ice melts, the temperature starts to increase. As you can now observe, during the period the water transforms into vapor, the temperature on the screen remains constant. Why do you think there was no change in the temperature during the periods of change of stake despite the fact that the kettle was on? Let's find out. All the readings will be stored in a .csv file format in a smartphone. You can access the data directly from a smartphone or you can send the file to your desktop. Plot the readings on a time versus temperature graph. The graph looks something like this. Observing the graph that the line is straight at 0 degrees and then at 100 degrees, why is the graph like this? When the temperature reaches 0 degrees, the attractive forces that keep the molecules together became very weak and the molecules start moving away from one another till the point the ice completely transformed into liquid water. This energy that is not seen as a temperature change is called latent heat. Latent stands for hidden. The energy that is used to change the phase from solid to liquid is called latent heat of fusion. Once the ice is completely turned into water, the temperature again starts to increase. At 100 degrees, the temperature again becomes constant because the energy is now used to convert water into vapor. This energy is called latent heat of vaporization. That's all for today. Thanks a lot for watching. If you like this video, go ahead and give it a thumbs up. For more such engaging videos, don't forget to subscribe to our channel.