Why do alpha particles cause neutrons to be released from beryllium?

[Tamoor]

First of this is not an homework question but just a bit of a theory i am having a bit of difficulty understanding. Secundly, hello!

James Chadwick discovered neutrons by sending alpha-particles from a radioactive source to a beryllium-plate, and that plate then sent out neutrons.

I don't understand, how sending alpha-particles can make the beryllium-plate (or any object) send out neutrons.

So if anyone would be so helpful as to tell me why this happens, i will be grateful

 

[mgb_phys]

An alpha particle (2n 2p) hitting Berylium (5n 4p) gives you carbon (6n 6p) and a spare neutron.

There's a movie of it here http://www-outreach.phy.cam.ac.uk/camphy/neutron/neutron5_1.htm