Brain Stuff video explains three reasons why dogs tilt their heads.
Be a Dog Detective is an article and video that illustrates what a dog's body language can tell you. The visuals show examples of happy dogs, scared dogs, territorial dogs, and dogs that want to play. Further, Be a Dog Detective shows you when it might be safe to pet a dog and when to leave a dog alone. The video is embedded below.
How Do Dogs "See" With Their Noses? is a TED-Ed lesson that provides a great explanation of how a dog's nose works. The most interesting part of the video is the explanation of how dogs' senses of smell allow them to identify friends, foes, and potential threats. The video is embedded below. You can find the full lesson here.