Physical- In the state of a physical change, you will get no difference since you started. If you get a lemon it is the same as when you are cutting it. Same as an apple for example. For a lemon, you have three steps,
- Get a lemon
- cut the lemon into pieces
- Have the lemon already freshly cut
As you notice there is no difference in the lemon.
Chemical- But as in a chemical change, when you have for example a lemon, and what if you burn it? As well a chemical change has three steps as well,
- Get a lemon
- Place the lemon into the fire
- Then the result will be; ashes.
That's the difference, how this helps. If not ask me!