At what point does a comet have the highest velocity?

Anything in orbit around the sun has the greatest speed when it's closest to the sun. That goes for the Earth too. We're closest to the sun and moving fastest during the first few days of January.

The radiation of the fire causes the saucepan to heat up. the conduction of the saucepan then to distribute the heat over the saucepan and to give heat to the water. the convection of the water distributing the heat within the water, till all the water is boiling