4.1a Energy exists in various forms: heat, electric, sound, chemical, mechanical, light.
4.1b Energy can be transferred from one place to another.
4.1c Some materials transfer energy better than others (heat and electricity).
4.1d Energy and matter interact: water is evaporated by the Sun s heat;a bulb is lighted
by means of electrical current; a musical instrument is played to produce sound; dark
colors may absorb light, light colors may reflect light.
4.1e Electricity travels in a closed circuit.
4.1f Heat can be released in many ways, for example, by burning, (friction),or
combining one substance with another.
4.1g Interactions with forms of energy can be either helpful or harmful.