July 2021

First Law of Thermodynamics: Interesting Everyday Examples

July 21, 2021

H2 Physics Tuition

Thermodynamics is a fascinating physics topic that students can learn in junior college. It is a branch of physics that focuses on the relationships between heat and other forms of energy. There are four known laws of thermodynamics, with the first law being one of the most fundamental principles of physics. It states that energy can neither be created nor destroyed; it can only be transferred or changed from one form to another.

This principle can be easily observed in your day-to-day life. From something as mundane as an ice cube melting to taking a bath, this phenomenon can occur so often that most of us overlook it or simply don’t even recognise it. As such, let us share four everyday examples so you can learn more about the first law of thermodynamics.

1. Taking a bath

Although you may not realise it, the first law of thermodynamics occurs every time you take a nice, long bath. Upon submerging your body into the bathtub full of water, you will initially feel the comfortable warmth of the water because its temperature is higher than your body temperature.

However, after some time, the heat from the water will be transferred to you, causing your body’s and the water’s temperature to correspond. When a bit more time has passed, you will notice that the water will begin to feel cool as the heat is lost to the atmosphere. Likewise, the heat in your body will dissipate, but not as much because your internal homeostatic mechanisms will help to keep your body temperature at a suitable level.

2. Photosynthesis

We know plants sustained themselves through photosynthesis when we were in primary school. However, do you know that this process is also an application of the first law of thermodynamic? The plants absorb the solar energy from the sun, before converting the solar energy into chemical energy. Not only does this process nourish the plants, but it also produces oxygen which is essential for our survival.

3. Melting of ice cubes

The melting of the ice cube is a classic example of the first law of thermodynamics occurring in our daily lives. When you leave an ice cube out in the open, you will notice it melting and converting to water in just a few minutes. This phenomenon happens because the ice absorbs the heat from the surrounding air, thereby cooling the air and changing the ice to water. In this example, the absorption of heat causes a change in the state of the ice.

4. Turning on a heater

We often like to turn on our heater to bathe in the warm water when it is cold outside. It is as simple as flipping a switch, but have you ever wondered how it works?

Our heaters are usually installed with a heating coil, which requires electrical energy to function. When the heater is turned on, the electrical energy travels through the heating coil and is converted into heat energy. Coldwater is brought in through a separate dip tube where it is heated by the heat energy generated, producing the warm water for your cosy bath.


As you can see, thermodynamics is a naturally occurring phenomenon. It is fascinating to see how physics impact our daily lives. You will get to learn more about this exciting topic when you begin your physics classes in junior college.

If you are interested in gaining a deeper understanding of thermodynamics and how it applies to your daily activities, you can consider enrolling in our JC physics tuition classes. At Best Physics TuitionTM Centre, we offer supplementary H2 physics tuition lessons to enhance your knowledge and help you score well on your physics exams!

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