The Comparison between Pentium Processing Devices and Celeron Processing Devices

My name is Donald; a 12 year old boy. I would wish to know the differences between Pentium Processing Devices and Celeron Processing Devices. What are some of the significant physical features they share in common? I would also like to know why the name Pentium and Celeron with respect to the different brands since they are all produce or made by Intel. Thank you.
