Thermal energy

Energy for mobility ... explore

...explore: On the "open seas" with a pop-pop boat

A pop-pop boat is a boat with a pulsating water engine. The simple motor operates without any moving parts. The only source of energy is a tea candle. At the rear of the boat underwater are two drinking straws side by side. Water is sucked in and out by these two drinking straws. Though the same amount of water will be sucked in as is pushed out, the boat moves forward in bursts and fits. The reason is that the water comes in from all directions but exits in only one direction.

	Build your own pop-pop boat
	Materias Long and short pieces of hard foam Ring of brass tube 2 drinking straws 2 Pins und 2 Staples Tea candle double sided and single sided tape, knife und pencil A water basin or a baking mould (water depth at least 5mm)
	Cut off 2 pieces from the long foam stick The foam pieces must be the same length as the short foam piece.
	Place the two cut pieces one on each side of the short foam board and push them halfway back Attach them with some tape on top and underneath.  Cut the boat's shape before assembling the pieces.
	Cut 2 cm from the long foam stick Stand this block up and attach two pieces of double sided tape on the smaller surface
	Attach the block exactly in the middle at the back of the boat form.
	Long brass tube (Materials from 15.2.2011) If your brass tube is about 13.5 cm long, you dont have to change it. Short brass tube (Materials until 14.2.2011) If your brass tube is about 7.5 cm long, you have to add two pieces of drinking straws.
	Short brass tube Cut off portions both of the drinking straws at 3cm under the bend, and cut 2 cm lengthwise. The mouthpiece of the drinking straws points towards the back. Push the drinking straws onto the brass tubes up until the bends and attach them to the brass with tape.
	Short brass tube Seal the bond between the straws and brass tube using tape in order for it to be airproof.
	Fix the tealight candle with two pins on the front of the upright foam block.
	Short and long brass tube Attach the brass ring over the candle with two staples on each side of the upright foam block.
	Commissioning the pop-pop boat Fill the brass tube with water under the tap. Fill until water comes out of the second drinking straw. On the way to the water basin, the drinking straws must be held upright.  No air may get into the openings.
	Close both openings with your fingers before putting the boat in the water.
	Take your fingers away only when the drinking straws are completely in the water. Video
Safety consideration: The water in the spiral reaches boiling temperature - ca. 100°C. Temperatures as of 65° C can burn you. Never take the boat out of the water before letting the spiral cool down. Filling a hot brass spiral can lead to steam escaping the spiral, which can burn you.
	Have fun and patience with the boat's slow advance.