Now, one more effect because of this negative slope is the following Because the slope is negative. If we keep our temperature constant, say, somewhere right here. So if we keep this temperature constant, we see that we can actually make the solid become a liquid by simply increasing our pressure. So at constant temperature, we can make a solid become a liquid by simply compressing it, increasing the pressure. But for this situation, we can't. The only way we get a solid to become a liquid is if we increase temperature.