ASVAB General Science Practice Test 797538

Questions 5
Topics Atom, Cell Membrane, Crust, Refraction, Solid

Study Guide

Atom

An atom is the smallest component of an element that still retains the properties of the element.

Cell Membrane

Animal cells are surrounded by a semipermeable membrane which allows for the transfer of water and oxygen to and from the cell. In plant cells, the cell membrane is surrounded by a somewhat rigid cell wall which provides the cell structure and support.

Crust

The crust is the Earth's outermost layer and is divided into oceanic and continental types. Oceanic crust is 3 miles (5 km) to 6 miles (10 km) thick and is composed primarily of denser rock. Continental crust is 20 to 30 miles (30 to 50 km) thick and composed primarily of less dense rock. The crust makes up approximately one percent of the Earth's total volume.

Refraction

Because different materials have different refractive indices, light changes speed when passing from one material to another. This causes the light to bend (refraction) at an angle that depends on the change in refractive index between the materials. The greater the difference, the higher the angle of refraction.

Solid

An element in a solid state has atoms or molecules that are constricted and do not move freely. Solids maintain a constant volume and shape and exist at a lower temperature than liquids or gases.