Physical change 1 is the answer
        
                    
             
        
        
        
The evidence that the universe is expanding comes with something called the red shift<span> of light. Light travels to Earth from other galaxies. As the light from that galaxy gets closer to Earth, the distance between Earth and the galaxy increases, which causes the wavelength of that light to get longer.</span>
        
                    
             
        
        
        
Answer:
it can be calculated by measuring the final distance away from a point, and then subtracting the initial distance 
 
        
             
        
        
        
When atoms lose electrons they become positively charged ! When atoms gain electrons they become negatively charged !