What are some examples of periodic waves?

What material do you need to make a tornado? How is energy transformed in a coal burning power plant? Why is the thermometer used today insted of the thormoscope? How many value of amplitude are there in one wavelength of a wave and how is the amplitude related to the energy of a wave? How long does it take for a 100 watt light bulb to cobsume 100 units of energy? What happens if you freeze air? What does the wrong side of the fabrics mean? What acceleration occurs if thefriction force is 4 N? The could shoot farther than other similar weapons? What is 4.4kilo in pounds? Why does hot oil splutter when droplets of water is dripped into it? How do you pick a lock with a hairclip? What are materials that allow light to pass through them? A campfire emits what 2 ranges of electromagnetic radiation? There are three collisions that make up every collision What happens during the third collision? 5000 pounds in kilograms? What are materials that move heat easily and quickly are called? Why use a sensor to capture physical data? What are 2 different types of wind? The change in position of one object compared to the position of another?

What are some examples of periodic waves?