Ideas of normal and abnormal are largely shaped by social standards and can have profound social ramifications. Learning Objective. Analyze the challenges inherent in trying to define normal and abnormal. What is considered normal changes with changing societal standards. Despite the challenges inherent in defining normal, it is still important to establish guidelines so as to be able to identify and help people who are suffering. This is the goal of the Diagnostic and Statistical Manual of Mental Disorders (known as the DSM-5), a publication in the field of clinical psychology.
Launching a water rocket. The rocket is in its peak with no water inside it. Water and gas are used in combination, with the gas providing a means to store energy, as it is compressible, and the water increasing the propellant mass fraction and providing greater force when ejected from the rocket's nozzle.
Have you noticed what happens if you let the air out of a balloon? The air goes one way and the balloon moves in the opposite direction. Rockets work in much the same way. Exhaust gases coming out of the engine nozzle at high speed push the rocket forward. Most modern launchers, such as Europeâs Ariane 5, are very complicated and weigh hundreds of tonnes at liftoff. Most of this weight is fuel, such as liquid hydrogen and liquid oxygen. Rockets need so much fuel in order to overcome Earthâs gravity. Only when they reach a speed of 28 000 km/h are they travelling fast enough to enter orbit.