Have the 13-year-old take two empty 2-liter plastic soda bottles and fill one of them with water, then use duct tape to adhere the two mouths of the bottles together so that the empty bottle is on top. Once secure, flip the bottles and swirl your arm in a clockwise or counterclockwise motion as the water pours from the top bottle to the bottom bottle. Swirl until the water itself begins to swirl, and watch the vortex type of motion that causes liquid and gases to travel in spirals around a center line. In the center of the vortex, which resembles a tornado, a small hole will appear that allows the air to rise inside the bottle.
Have 13-year-olds plant two radish seeds in separate containers. Place both radish containers in a well-lit window, but keep them at least 20 feet apart from each other. Have them take a magnet and place it next to one of the two containers, then water the containers as directed on the seed package. The radish plant near the magnet will grow shorter and lean toward the magnet. The other plant will grow taller and straight.
Ask 13-year-olds to design a container that will allow an egg to be dropped from a height of 8 feet without breaking the egg. Give them parameters as to what types of materials they can and can't use. Allow them to practice drops from a ladder to test their inventions.
Conduct this experiment outdoors in an open area. Use a 35mm plastic film canister with the lid. Instruct all participants to wear safety goggles. Place half of a fizzing antacid tablet inside the canister and quickly add a teaspoon of water. Snap on the cap and place the canister on the ground with the cap side down. Ensure that all participants are standing at least 2 meters away. In approximately 10 seconds, you will hear a loud pop, and the film canister will launch into the air.