1. Refraction: This occurs when a wave passes from one medium to another, causing it to bend. Think of a straw in a glass of water - it appears to bend at the water's surface because light waves travel at different speeds in air and water. Ocean waves also refract as they approach the shore, causing them to bend and align with the coastline.

2. Reflection: This happens when a wave bounces off a surface. Imagine a ball bouncing off a wall. Sound waves also reflect, which is why you can hear echoes. Light waves reflect off mirrors, allowing us to see ourselves.

3. Diffraction: This is the bending of waves as they pass through an opening or around an obstacle. Think of water waves spreading out as they pass through a narrow gap in a breakwater. Diffraction also explains why we can hear sounds even when we're around a corner – the sound waves diffract around the corner and reach our ears.