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3rd grade · Science · Unit 2 of 12

Speed & Motion

Fast and slow, why things keep moving, and what changes how quickly motion changes.

What your child practices

Practices speed as the distance an object travels in a certain time, inertia (objects keep doing what they are doing until a force acts), and how mass and force affect how quickly motion changes.

Alabama Course of Study content standard: 3.1; 3.2 · how forces change motion, and patterns that predict how things will move

How we explain it

Children can open this short lesson before they practice.

  1. Speed is how far something travels in a certain time.
  2. Things keep doing what they are doing until a force acts on them.
  3. Friction slows things down. Rough grass has more friction than smooth ice.

Example: A runner goes 10 km in one hour. A walker goes 5 km. Who is faster? Both took one hour. 10 km is farther than 5 km. Answer: the runner

Speed & Motion in Alabama

In the Alabama Course of Study, this is unit 2 of 12 in 3rd grade Science, after Pushes, Pulls & Forces and before Magnets and Static.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Alabama State Department of Education (ALSDE)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Which is easier to speed up with a push?

    • A cart full of bricks
    • An empty cart
    • A full cart

  2. Question 2

    After you stop pedaling, a bike slows down because of…

    • friction and air
    • more energy
    • it getting younger

  3. Question 3

    A rolling ball keeps going until a force…

    • slows or stops it
    • gives it a name
    • thanks it

  4. Question 4

    A snail goes slowly because it…

    • travels a short distance in a long time
    • is heavy like a rock
    • has no body

  5. Question 5

    A car travels 60 km in one hour. A bike travels 15 km in one hour. Which has greater speed?

    • they are the same
    • the car
    • the bike

  6. Question 6

    Which object is moving at constant speed?

    • A ball being dropped and speeding up
    • A car braking
    • An elevator moving 1 floor every 2 seconds the whole way

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