Science lesson plan · 3rd grade (Year 4 in England) · 45 minutes
Which way will it move? Predict from the forces
Forces and motion
CCSS NGSS.3-PS2-1England: KS2 Y3 Forces and magnetsEngland: KS3 Physics: Motion and forces (balanced forces)
Objective and success criteria
Students will: Which way will it move? Predict from the forces.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Balanced and unbalanced forces
Leads to: Tug of war: add up forces and find the winner; Use patterns of motion to predict what happens next; Contact forces and forces that act at a distance
Materials: Force meters, Toy cars and ramps, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Balanced and unbalanced forces). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Balanced forces: which statement is NOT true? (When forces are balanced, a still object stays still. / Forces are measured in newtons (N). / When forces are balanced, a moving object keeps moving at the same speed in the same direction. / A still object has no forces acting on it.) → A still object has no forces acting on it.Prompt: Can something move steadily with balanced forces?
Hook · 5 min
- Drop a sheet of paper and a scrunched-up sheet together and ask why one falls faster.
- Share the objective: Which way will it move? Predict from the forces. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A cyclist pedals harder than the air and road push back. What happens?
- Step 1: Unbalanced forward force makes the bike speed up.
- Step 2: So the answer is: The bike speeds up.
- Answer: The bike speeds up.
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A book lies still on a table. Gravity pulls it down. Why doesn't it fall? (The table pushes up with an equal force, so the forces are balanced. / There is no gravity indoors. / The book is holding on to the table. / The book is too light for gravity.) → The table pushes up with an equal force, so the forces are balanced.Prompt: Is there a force pushing up as well as down?
- True or false? If two forces are unbalanced, the object moves towards the smaller force. (True / False) → FalsePrompt: Compare the sizes and directions of the forces.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Two teams pull a rope equally hard. What happens to the rope? (It stays where it is. / It snaps at once. / It moves up into the air. / It moves towards the bigger team.) → It stays where it is.Prompt: Are the forces balanced or unbalanced?
- True or false? An object with balanced forces must be still. (True / False) → FalsePrompt: Compare the sizes and directions of the forces.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Balanced and unbalanced forces.
- Use concrete materials: force meters.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Tug of war: add up forces and find the winner; Use patterns of motion to predict what happens next; Contact forces and forces that act at a distance.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-3.
Free lesson plan from eurekami.com/lesson-plan-builder