ice on a windscreen would dissapear as you drive along even without the heater on.Explain why this happens

The ice on a windscreen tends to disappear as you drive along, even without the heater on, due to a combination of different factors:

1. Friction: As you start driving, the movement of the car generates friction between the windscreen and the air. This friction produces heat, which can help to raise the temperature of the windscreen.

2. Ambient temperature: When you drive, particularly at higher speeds, the wind hitting the windscreen can increase the temperature of the ice. Even if the outside temperature is below freezing, the contact with the slightly warmer air can cause the ice to slowly melt.

3. Sunlight: If there is sunlight, it can have a significant impact in assisting the ice to melt. Sun rays carry heat, which can increase the temperature of the windscreen and accelerate the melting process.

4. Car interior temperature: When you are driving, the temperature inside the car tends to rise due to the engine generating heat. This warmer air circulating inside the car can indirectly contribute to melting the ice on the windscreen.

Combined, these factors can lead to the gradual disappearance of ice on the windscreen as you drive along, even without the heater on. However, it's important to note that using the heater or defrost setting will considerably accelerate the ice melting process, as it blows warm air directly onto the windscreen.