Science · Unit 1 · Weeks 1–6
Forces & Motion
The big idea
Your child learns that a force is a push or a pull, and that balanced forces leave motion unchanged while unbalanced forces make an object start, stop, speed up, slow down or turn. Hands-on tests with toy cars, ramps and rubber bands show friction at work, and magnets and charged balloons show forces that act without touching. The unit ends by finding patterns in pendulum swings and ball bounces and using them to predict.
Standards in plain words
- 3-PS2-1 Plans and carries out investigations to show what balanced and unbalanced forces do to an object's motion.
- 3-PS2-2 Observes or measures an object's motion to find a pattern that can predict what it will do next.
- 3-PS2-3 Asks questions to find cause-and-effect relationships for magnetic or electric pushes and pulls between objects that are not touching.
What mastery looks like
- Draws force arrows and says whether forces are balanced or unbalanced and what will happen to the motion.
- Runs a fair test of friction on different surfaces, keeping the car, ramp and start the same.
- Tests objects with a magnet and explains that magnets attract iron and steel, not all metals.
- Shows that like magnet poles repel, opposite poles attract, and a charged balloon pulls on tissue bits without touching.
- Uses a pattern in swings or bounces to predict the next result and checks the prediction.
Materials
- Toy car and a hardcover book for a ramp
- Rubber band, string and masking tape
- Ruler or tape measure
- Fridge magnet, paper clips, foil and a coin
- Balloon and tissue-paper bits
- Small ball
- Science notebook
Anchor texts
- Reading About Our World passages: 'Forces All Around You' (Week 1), 'The Force That Slows Things Down' (Week 3) and 'Magnets and Static: Forces at a Distance' (Week 5)
- Video hub topics: pushes and pulls, balanced forces, friction, magnets and electric forces, and what changes a pendulum's swing
Watch across the unit
Watch for: Thinking an object sitting still has no forces on it.
Try: Have your child hold a book on a flat hand and ask, 'What would happen if your hand stopped pushing up?'
Watch for: Believing all metals stick to magnets, or that smooth surfaces have no friction.
Try: Test foil and a coin with a magnet, and slide a book on the smoothest surface you have: it still slows and stops.
Watch for: Changing more than one thing in a test, such as pushing the car on some trials.
Try: Keep a 'same every time' list and release the car by lifting a finger, never pushing.
Pacing
Short week: Keep Monday's hands-on investigation and a short Friday check where your child says what the evidence shows. The science notebook entry can be done aloud, and the second trial of a test can be skipped if the first was careful.
Flex week: Week 5 is the flex week. Retest the two big mix-ups ('all metals are magnetic' and 'smooth means no friction'), draw force arrows, or enrich with a marble run that uses friction and a test of what a magnet's pull can pass through.
Week by week
| Week | Topic | Investigation |
|---|---|---|
| Week 1 | Forces are pushes and pulls | Sort pushes and pulls |
| Week 2 | Balanced & unbalanced forces | Tug-of-war investigation |
| Week 3 | Friction | Test surfaces with a rolling car |
| Week 4 | Magnets & static electricity | Test which materials a magnet attracts |
| Week 5 | Flex week | Choice investigation |
| Week 6 | Patterns of motion | Pendulum and bounce patterns; Unit 1 test |