132 ELEMENTARY GENERAL SCIENCE CH. ix 



19. Describe an experiment which indicates that " Heat is a form 

 of Energy." 



20. How would you prove that " when bodies are electrified they 

 are endowed with energy and can produce motion and heat " ? 



21. Name some forms of energy, and give instances of the trans- 

 formation of energy from one form to another. 



22. How would you prove that the destruction of the visible 

 motion of a body is often accompanied by the appearance of heat ? 



23. When a brake is applied to a wheel of a train red-hot sparks 

 are seen. What are these sparks, what is the source of their heat 

 and why do they soon disappear ? 



24. Energy may be defined as the ability to do work. Give 

 instances to show that heat and chemical action are forms of energy 

 thus described. 



25. Define the meaning of ilie word " energy," and give three or 

 four examples to prove that a moving body possesses energy. 



