Wave simulator reflection

I learned new things whit that site. It was cool looking at waves and sound and light. I saw in the waves pert that some of the waves were bigger and some smaller. It was really interesting looking at the amplitude of the wave and the frequency. It made me understand better what was a frequency and amplitude of the wave. I first started playing around with it to see what could it do whit that. At the end I got the habit of using it and I started looking at the graph, the frequency level and the amplitude of the wave.

http://phet.colorado.edu/en/simulation/wave-interference