Firstly, students should be able to define what a transformation is. A transformation is a change in the position, shape, or size of a geometric figure. There are four basic types of transformations: translation, reflection, rotation, and dilation.

Students should understand the properties of each type of transformation. For example, a translation is a movement of a figure without changing its shape or size, while a reflection is a transformation that flips a figure across a line of symmetry.

Next, students should be able to perform transformations on geometric figures. They should be able to use coordinate notation and describe the effects of transformations on the coordinates of points.

Finally, students should be able to solve problems involving transformations. They should be able to use transformations to determine congruence, symmetry, and similarity of geometric figures.

In summary, understanding transformations is a key aspect of geometry for grade 8 students.