Aerodynamics are rich in knowledge of physics, single cylinder combustion engine.  Engine principle is intuitive, educational toys, teaching experimental equipment can effectively cultivate children's interest in learning can also be used for classroom teaching, more intuitive and easy to understand.    Description: Name:Double Cylinder Engine Model;  Material:Aluminum alloy,glass;  Color:Silver gold;  Size:160x87x110mm;    Instructions: -The engine model on the horizontal position by hand toggle the flywheel to see if smooth, check the connection rod is normal, whether the cylinder oil and dust, and if so, please use toilet paper to erase Not smooth. Toggle the flywheel feel pressure rebound within the cylinder body is a normal phenomenon, the cylinder is sealed.  -The packing bag of alcohol lamp cotton wear into the metal cap lamp.  -Please go to the pharmacy to buy 95% purity alcohol, anhydrous industrial alcohol better. Fill the alcohol lamp to less than two-thirds.  -Alcohol lamp to the alcohol lamp, at the premise of ensuring safety, ignite the alcohol lamp about 2 minutes after the flywheel, until the flywheel automatic operation so far, the whole process of heating, hands may not touch.  -Led lights can be directly into the generator output interface, if not inserted, the exchange can be positive and negative, led a long foot for the cathode.    Note: -This engine is perfectly for kids over 12 years old.  -There will be the operation of steam,when the steam too much, the engine will stop working,  inside and outside the needle often set aside to reduce friction.  -Do not rotate the nut too tightly, otherwise the glass is broken, if the piston is cracked, can be bonded with glue.  -The alcohol lamp wick do not touch the glass, do not get too tight ring.  -Pulling the piston connecting rod can not force the front end, because the front end is easy to break.  -Because the production batches are different, the appearance of the product is different, please make sure you don’t mind.  -The color of the bulb is shipped randomly.    Package included: 1  Set of Stirling Engine model