How do Waves Interact in a tub of water with:

1) No barriers
2) One barrier
3) Two barriers

This week in science class we did a lab studying waves, and how they travel through water without barriers, with one barrier and with two barriers. We used a small tub, water, 2 pens, and clay barriers. What we did was fill up the small tub halfway with water. Then, we used 2 pens to make up and down movements in the tub, causing waves. We did this continuously and observed the waves the pens motion made. Our first experiment, with no barriers, went pretty straightforward. We created waves with two pens on opposite/different corners of the tub, and watched the waves the movement of the pens created. Basically, the waves traveled until they met an obstacle, such as the side of the tub or another wave. When the two waves interfered, they only overlapped a small part, and then disappeared. We tried moving the pens faster and faster up and down and they made even more waves, but they still went invisible after they interfered. That is probably because there's a stronger force on the opposite side, like the stuff we studied last year. We did three tests and then sketched them in our notebooks. Then we tried it with one barrier. Just as I had suspected, the waves couldn't travel through the barriers. This also meant that the waves now had three obstacles; the side of the tub, the opposite wave, and the clay barrier. The waves continued traveling, but they were weaker than the first round without barriers. We did three tests putting both the barriers and the pens in a different position. When the waves went around the barriers they caused diffraction, or the bending of waves as it hits a barriers. The waves then split up and caused ripples over the half the tub. Lastly, we added another barrier, so that we had two barriers, the side of the tub and the opposite wave interfering with the movement of the waves. We did several tests, and they were all pretty similar to each other. The waves couldn't pass through the barriers, and they were even less strong than the ones with one barrier. Diffraction split them up even more than with only one barrier. One experiment we tried that was really interesting for me was when we had one pen at a corner of the tub, and then closed it in there with the barriers. All the waves inside the enclosed area started moving really fast, and bouncing off barriers and walls, while the other pen, outside the enclosed area, made large waves covering almost half the tub. The two waves never inter-lapped, it was as if they were made in two different tubs. This really shows how effective barriers are and how well we are able to control waves.

Below are some pictures I took from this experiment.