How could you heat 1 liter of cold water?

To heat 1 liter of cold water, you can use a stovetop by placing the water in a pot and boiling it over medium to high heat. Alternatively, you could use an electric kettle, which is often faster and more energy-efficient. A microwave is another option; simply place the water in a microwave-safe container and heat it in short intervals, stirring in between. Lastly, you could also use a hot plate or immersion heater for quick heating.