Standard 3/Middle School/Benchmark 1
Benchmark Question: How can the motion of objects in two
dimensions be described and compared qualitatively?
Focus Question: How can the motion of objects be
described and compared in terms of direction and speed?
While students observe, the
teacher will place a checker on a table and flick it with a finger, roll a
toy car in a straight line across the floor, and drop a ball from a table.
The teacher will ask the students to describe the path of each object and
to draw a conclusion about the direction of motion. Students will realize
that each object moved in a straight line.
The teacher will tell the
students that scientists call such motion “regular straight-line motion.”
The teacher will discuss other examples with students: a bicycle continues
moving in the same straight line if the front wheel is not turned, and
people lurch forward in a bus, train, or car when it stops quickly.
Working in small groups,
students will roll marbles across a smooth, level surface. Students will
see that the marbles always go in straight lines. Then students will roll a
single marble and blow on it from the side as it travels. Students should
discuss how this changes the motion. They should record their observations.
Next, one student will hold
a strip of thin cardboard on edge and curve it slightly. S/he will roll a
single marble into the curve of the strip and discuss any change in its
direction. Students will write their ideas about the effect of the
cardboard and the effect of the blowing on the motion of the marble.
Students will begin to realize that all moving objects travel in a straight
line (e.g., hockey pucks, rain drops) unless influenced by other forces.
Continue the study of the
motion of objects by having students design and conduct an experiment to
determine what variables affect the speed of various moving objects.