Sound travels in waves. Sound must travel through a solid, liquid or gas to be heard. Sound is effected by the material through which it travels. Different materials can produce different sounds. Developments in sound technology can be helpful or harmful to our hearing.
Water is matter because it has mass and takes up space.
Water has many properties. Water is used in many ways. The size, shape, mass, or material of an object affects whether it will sink or float in water. Buoyancy is related to sinking and floating. Addison-Wesley focuses on animals in this unit.