So my friend and I were having a discussion at the bar and he mentioned he didnt believe in Newtonian mechanics completely. I asked why and he said:

Well i don't quite understand the conservation of energy, if a car is travelling around 50 mph and hits a massive block of sponge, then in what way is the energy dissipated in the sponge? It will bounce off of it but what happens to the rest of the energy? It doesnt make much sound or heat?

My argument was that the sponge has many pockets of air within and the energy of the car pushes the air out of them and compresses them. Also, that the sponges molecular structure may have lots of room to absorb energy...

PLEASE ENLIGHTEN ME!

At 50 mph it will make a sound all right. The gas escaping the sponge will feel hot. There will also be tearing in the fabric of the sponge.
So the energy is converted to sound, air velocity, heat, chemical energy (broken bonds) and rebound kinetic energy (the bounce).

Mmm spongecake..

no really serious now

Thank you hopefully he will regain his trust in good old Isaac.