Science
Strand:
Grade: 3rd (from 4th)
SCI.IV.3.2
Using Scientific Knowledge in Physical Science
- Motion of Objects
Standard:
All students will describe how things around us move, explain why things
move as the do, and demonstrate and explain how we control the motions
of objects
Benchmark:
Explain how forces, pushes or pulls are needed to speed up, slow down, stop,
or change the direction of a moving object.
Constructing and Reflecting:
SCI.I.1.1 - Generate reasonable questions about the world based on observation.
SCI.I.1.4 - Use simple measurement devices to make measurements in scientific investigations.
SCI.I.1.5 - Develop strategies and skills for information gathering and problem solving.
SCI.I.1.6 - Construct charts and graphs and prepare summaries of observations.
SCI.II.1.1 - Develop an awareness of the need for evidence in making decisions scientifically.
Vocabulary / Key Concepts
Context
Changes in motion – speeding up, slowing down, turning.
Common forces – push, pull, friction, gravity. Size of change
is related to strength of push or pull.
Playing ball, moving chairs, sliding objects.
Knowledge and Skills
Resources
Coloma Resources:
Students will demonstrate and describe the motion of
objects and investigate the force that makes it move.
Descriptions should include:
• Friction – force that makes moving object slow down
due to surface contact
• Gravity – force that makes things fall to Earth
• Other Pushes or Pulls – forces exerted by people, and
machines
An object moves in a straight line & at a constant speed
as long as no force acts on it. When a force acts on an
object, it can speed up the object’s motion, slow it down
or change it’s direction. The greater the force, the greater
the change. Friction is the force that makes objects stop
moving when it looks like there are no other pushes or
pulls on it.
Simple Machines Kit
Discover the Wonder (Scott Foresman) – Grade 3
Module C, pages 42-47
Nankivell, Sally. Science Experiments with
Force. Watts, 2000
Wells, Robere. How Do You Lift a Lion
Whitman, 1996
Instruction
Assessment
Benchmark Question: What forces are needed to impact
the motion of a moving object?
Using the data from the Instructional Example,
students will answer the following questions:
1. Which surface required the most force?
Why?
2. Which force took less effort in the sand?
3. If you were pulling a heavy load, which
surface would you like to travel on? Why?
4. Why are bowling alleys smooth and hard?
Focus Question: Why do things move as they do?
Students will brainstorm in small group situations
when forces act upon an object to change its speed
or direction then report to the entire class. (e.g.
merry-go-round = speed; swing = direction; baseball
& bat = speed and direction)
See scoring below.
In small groups, students will experiment with forces
needed to push or pull an object. Students may use a
wagon over a given course which contains a variety of
1. needs to include sand and more friction
2. needs to include pull
surfaces such as grass, sand, and concrete as well as over
terrain (hills, curves, flat surfaces) Students will measure
3. needs to include concrete, and reduced
the course, the time it takes to complete the course and
friction and force.
making written observations of the difficulty navigating
4. needs to include less force needed and very
the course. Students will navigate the course three (3)
little friction.
times. First they will push the object, next they will pull
the object, and lastly they may use a combination of push Achieving standard with 3 out of 4 correct.
and pull to use the least amount of force needed to
navigate the course. In their journals, students will explain
why they chose to push or pull during their last trial.
Each student in the group will push an object as far as
they can, measure the distance, and calculate the average
distance or compare distances pushed, analyze data.
Teacher Notes:
Describe how things around us move, explain why things move as they do, and demonstrate and explain how we
control the motion of objects.
Young children should become acquainted with the scientific descriptions of the motion of objects, which
generally includes discussion of speed, direction and changes in speed or direction. The understanding of the
force/motion relationship can become increasingly quantitative, as the students get older. Instruction should be
included which will help students overcome a common belief that sustained motion always requires sustained
force.
As older elementary children study motion, they discover that an object moves in a straight line and at a
constant speed as long as balanced forces act on it. When a force acts on an object, it can change speed or
direction. The greater the force acting on the object, the greater the change in the object's speed and/or
direction. Scientists attribute all changes in motion to forces, pushes, or pulls exerted by people, machines,
magnets, friction and gravity. As students reach middle school level, they will continue to find the description of
motion challenging and need to be aware that changes in speed or direction are associated with unbalanced
forces.
Early elementary students can develop a foundation for understanding magnetic attraction through various
investigations of magnetism. Determining categories of objects that are attracted to a magnet, distances
through which a magnet will attract objects and how many small objects a particular magnet will attract helps
children consolidate their experiences into scientific knowledge.
Middle school students can analyze the attractive and repulsive forces exerted by electrical and magnetic
fields and experiment to create magnetic objects with the use of electric current. Experiences with
electromagnets, doorbells, speakers, and magnetic switches assist students in understanding the relationship
between magnetism and electricity. Simple electric motors work when a permanent magnet is combined with
an electromagnet. Electricity is converted into magnetic fields, which in turn causes something to move.
Electrical circuits are an aspect of electricity and magnetism encountered every day.
Elementary students should be able to understand that simple machines are devices controlling forces. A lever
can transform a small downward force into a large upward force thus making a task easier. Simple machines
help us to accomplish tasks that would otherwise be impossible. Young children can see simple machines all
around them. Homes and playgrounds offer rich experiences for children to experiment with concepts related
to simple machines. By middle school, students should be able to not only identify the types of simple
machines but also design applications for use of them. High school students should be able to analyze
patterns of force and motion in complex machines. They should be able to explain how the machine works and
predict the effect changing a component will have on the machine.