The black line above node 1 crosses through zero. To the right of node 1 the arrows point to the left and get longer away from the node. The arrows showing displacement are turned through 90 degrees and plotted on the line graph above. The line shows the displacement of air in the tube. Notice the other nodes, they alternate from high density to low density.
Arrows point toward high density nodes and away from low density ones.
In the second frame, an eighth of a cycle later, the dense regions of air are expanding into the less dense regions. The displacement in the second frame is less at every point than in the first. The colors are more muted showing less density contrast. The line graph has lower amplitude. The ends of the tube should still be yellow.