Bella is designing a model of a longitudinal sound wave for her science classroom. Which of the following pieces of information should Bella include in her model? Choose the two statements that apply.
A. Sound must travel through a material to transfer energy.
B. Sound must travel through a vacuum to transfer energy.
C. Rarefaction and compression are properties of longitudinal waves.
D. Crests and troughs are properties of longitudinal waves.

The energy conversions that occur when a grapefruit falls from a tree is;

Potential energy ---> kinetic energy ---> potential energy

Combustion reactions occur in the presence of oxygen gas- True

Energy is the ability to do work - True

A renewable energy source is one that is replaceable - True

Light energy is emitted by certain organisms such as fireflies and glow-worms - True

Sound energy cannot travel through air - False

Heat energy cannot travel through a liquid for example water - False

Explanation:

According to the first law of thermodynamics, energy can not be created nor destroyed but is converted from one form to another. When a grapefruit falls from a tree, the energy conversion is as follows;

Potential energy ---> kinetic energy ---> potential energy

Combustion reaction refers to a reaction where a substance is burnt in oxygen to produce heat and light.

Energy is defined in science as the ability to do work. Renewable energy can be replaced. A typical example is solar energy.

Light energy is emitted by certain organisms such as fireflies and glow-worms.

Sound is a mechanical wave hence it must be transmitted through a medium. The medium through which sound waves are transmitted is air.

Heat travels through any thermal conductor. Water is an example of a good thermal conductor. Heat indeed travels through different liquids.