Drag and Upthrust

Overview

This 60-minute lesson is designed for Year 5 students (ages 9–10) to understand the scientific concepts of drag and upthrust. It aligns with the National Curriculum for England’s KS2 Science Programme of Study: Forces. Using interactive explanations, hands-on experiments, data recording, and PowerPoint slides, students will explore how forces such as drag and upthrust affect objects in water and air.

---

Curriculum Links

National Curriculum (England) KS2 Science — Forces

• Pupils should be taught to:
  • Explain that unsupported objects fall towards the Earth because of the force of gravity acting between the Earth and the falling object.
  • Identify the effects of air resistance, water resistance and friction, that act between moving surfaces.
  • Recognise that some mechanisms, including levers, pulleys and gears, allow a smaller force to have a greater effect.

Learning Objectives:
By the end of the lesson, pupils will be able to:

• Define and explain the forces of drag and upthrust in simple terms.
• Describe how drag affects objects moving through air and water.
• Understand upthrust as the upward force acting on objects submerged in fluid.
• Conduct simple experiments to observe drag and upthrust and record data systematically.

---

Resources

• PowerPoint slides (covering key concepts, images, diagrams, video clips)
• Variety of small objects (plastic balls, paper planes, toy boats, sponges)
• Clear containers (large transparent tubs or bowls) filled with water
• Stopwatch or timer
• Rulers or measuring tapes
• Data recording sheets (tables for timing drops, measuring distances, recording float/sink observations)
• Towels and aprons (to manage water spills)
• Whiteboard and markers
• Camera or tablet (optional for recording experiments)

---

Lesson Structure

1. Introduction (10 mins)

• Greet the class and share the learning objectives clearly.
• Use the PowerPoint to introduce the terms drag and upthrust with age-appropriate definitions:
  • Drag: “A force that slows down objects moving through air or water.”
  • Upthrust: “A force that pushes objects up when they are in water or other liquids.”
• Show simple animation/video clips embedded in the slides demonstrating a falling leaf slowed by air resistance (drag) and a boat floating on water (upthrust).
• Ask the class to give examples of situations where they have seen drag or upthrust (e.g., feeling wind on their face, objects floating or sinking).

2. Demonstration with Class Discussion (10 mins)

• Use a plastic ball and a paper plane to demonstrate drag:
  • Throw the ball gently and then throw the paper plane. Ask which experienced more resistance (drag) and why.
• Drop a small plastic toy and a sponge in a container of water simultaneously to demonstrate upthrust and sinking.
• Prompt discussion on what they observed, linking to vocabulary on slides.

3. Group Experiment Stations (25 mins)

Divide the class into 9 groups of 3 students, giving each group a set of materials and data sheets.

Station 1: Investigating drag in air

• Students throw paper planes or feather-like objects to see how shape affects air drag.
• Record distances flown and hypothesise which shapes create more drag.

Station 2: Investigating drag in water

• Students push different shaped objects through water and observe resistance felt and speed.
• Time how long it takes different objects to move a set distance in water.

Station 3: Investigating upthrust

• Students place objects into water, predict whether they will float or sink, then test and record results.
• Measure how much of the object is submerged versus above water surface to discuss upthrust.

Teachers circulate to support and ask probing questions, ensuring safety and accurate data recording.

4. Data Analysis and Group Sharing (10 mins)

• Groups share key findings with the class (e.g., “The paper plane with a bigger wing flew slower because of more drag.”)
• Use the interactive whiteboard to input some group data and compare results visually.
• Highlight patterns and reinforce scientific vocabulary.

5. Plenary and Review (5 mins)

• Recap key points using a quiz on the PowerPoint (e.g., multiple choice or true/false questions).
• Ask pupils to explain in their own words what drag and upthrust are.
• Set one quick reflective question for each pupil to write on a mini whiteboard: “Why do boats float?” or “How does drag affect a cyclist?”

---

Assessment

• Observe pupils during experiments for understanding and engagement.
• Review completed data sheets for completeness and accuracy.
• Use plenary quiz answers and pupils’ verbal explanations to check concept comprehension.
• Optional: short written exit slip asking pupils to describe drag or upthrust.

---

Differentiation

• Support: Provide pre-labelled diagrams and sentence starters for recording data and findings.
• Extension: Challenge advanced learners to design their own experiment to test shape impact on drag or to calculate simple averages of timings.

---

Cross-Curricular Links

• Maths: Measuring, timing, recording and comparing numerical data.
• English: Using scientific vocabulary in explanations, structured speaking during group presentations.
• Computing: Using the interactive whiteboard and presentation software.

---

Teacher Notes

• Prepare PowerPoint in advance with visuals, animations, and clear definitions.
• Organise equipment efficiently to minimise transition time between activities.
• Emphasise safety around water and encourage respect among peers during experiments.
• Encourage curiosity by asking “what if” questions during activities to deepen conceptual thinking.

---

This lesson plan offers a practical, engaging approach to key KS2 forces, fostering scientific enquiry skills and conceptual understanding, aligned with the National Curriculum for England.