Question

how can you verify newtons second and third law?

Answer 1

I'm assuming you're talking about the 2nd and 3rd laws of motion:
2: F = MA
3: Every action -> equal and opposite reaction

The 2nd one is easy, you can either try a mathematical proof, or by experiment. For experiment I would try hanging a mass from a spring and resting the mass on a scale. You can then accelerate the scale or mass and record how it effects the weight the scale reports. A larger acceleration implies a larger force

For the third law you could look into newtons equation for the gravitational force. The 3rd law implies with objects 1 and 2
F(1 on 2) = -F(2 on 1)
You can compute how much the sun is pulling on the earth in order for it to maintain a steady orbit, then you can turn around and use that to compute (through the 2nd law) how hard the earth is pulling the sun! It's an exercise in futility but is fun none the less :D

Answer 2

FOR SECOND LAW OF MOTION
You can show this by using a pair of roller skates of equal mass. Keep them lined up together at a line. Then, at the same time, push both of them, giving one of them a harder push than the other. You will find that the one that has been pushed harder moves faster and travels more distance. Since the mass is equal for both skates, the greater acceleration is in the skate that you exerted greater force on.

FOR THIRD LAW OF MOTION
You can take two similar spring balances. Hand one to your friend and take one in your hand. How interlink the hooks of the two balances and pull them away from each other. You will find that the pointers of both show the same reading. This shows action and reaction are equal and opposite.