Strand IV
Use Scientific Knowledge from the Physical Sciences in Real-World Contexts


Science/Strand IV
Content Standard 3
All students will describe how things around us move and explain why things move as they do; demonstrate and explain how we control the motions of objects; and relate motion to energy and energy conversions. (Motion of Objects)


Science/Strand IV/Content Standard 3
Middle School


Science/Strand IV/Content Standard 3/Middle School
Benchmark 1
Qualitatively describe and compare motion in two dimensions.

Benchmark Clarification

Most students have not practiced describing motions. They use the word speed with relation to fast and slow, but not increase and decrease. They need to learn how to describe the direction of motion: straight path, curved path, circular path.

For example, a thrown ball travels in a curved path. The speed changes as friction with the air slows the ball as it moves horizontally. The pull of gravity pulls the ball down, so the path of the ball curves downward.

Students will:

  • Describe and compare the motion of objects using key concepts in terms of speed and direction

Key Concept / Real World Context / Instructional Example / Assessment Example / Resources


Science/Strand IV/Content Standard 3/Middle School/Benchmark 1
Key Concept
Two-dimensional motion:

  • up
  • down
  • curved path


  • direction
  • change in speed
  • change in direction


Science/Strand IV/Content Standard 3/Middle School/Benchmark 1
Real World Context
Objects in motion:

  • thrown balls
  • roller coasters
  • cars on hills
  • airplanes


Science/Strand IV/Content Standard 3/Middle School/Benchmark 1
Instructional Example

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.

Constructing: (SCI.I.1.MS.1), (SCI.I.1.MS.2), (SCI.I.1.MS.3), (SCI.I.1.MS.4), (SCI.I.1.MS.5).

Reflecting: (SCI.II.1.MS.2).


Science/Strand IV/Content Standard 3/Middle School/Benchmark 1
Assessment Example

Small groups of students will set up two identical ramps with distinctly different slopes (one steep slope and one gradual slope). Before using two identical toy cars, each student will write a prediction about which car will go down the ramp the fastest and which car will go down the ramp the farthest. Each student will record his or her hypothesis. The students will take turns releasing both cars at the same time. Students will write observations of what happened and explain reasons why their prediction was correct or incorrect.

(Give students rubric before activity.)

Scoring Rubric






Accuracy of hypothesis

Does not write a hypothesis and contains possible misunderstandings.

Provides partial hypothesis with possible misunderstandings.

Provides hypothesis with few exceptions.

Provides a thorough and accurate hypothesis.

Completeness of conclusions

Does not write a complete conclusion or conclusion is erroneous.

Writes a conclusion based on erroneous information or correct information with no details.

Writes a conclusion based on correct information with some details.

Writes a conclusion based on correct information with many details.


Science/Strand IV/Content Standard 3/Middle School/Benchmark 1


Road Rally Activity. AIMS.