Filtration Process Explained

Overview

Students learn how filtration separates mixtures using a physical property of materials and identify where filtration is used in daily life. This lesson builds on earlier understanding of solutions and mixtures by focusing on one separation technique and explaining the steps clearly.

Learning intentions

• Students will explain the filtration process and its uses using correct scientific language.
• Students will identify how the filter (material and pore size) affects what passes through and what is retained.
• Students will interpret results from a filtration demonstration and link observations to the method.
• Students will follow a written sequence to describe filtration steps accurately.

Success criteria

Students can…

• Describe the filtration steps in order (pour, wait, collect filtrate, observe residue).
• Explain what happens to the solid particles and the liquid during filtration.
• Match evidence from a demonstration to the idea that filtration separates by particle size and the filter’s properties.
• Answer multiple-choice questions that show understanding of filtration uses (e.g. water cleaning, coffee filters).

Curriculum links

• SC4-SOL-01 — Students explain how the properties of substances enable separation in a range of techniques.
• SCLS-SOL-01 — Students describe the properties of familiar substances and materials (filter material and particle behaviour).
• SC4-WS-01 — Students use scientific tools and instruments for observations (using filter setups and recording observations).
• SC4-WS-04 — Students follow a planned procedure to undertake safe and valid investigations (carrying out filtration safely and in sequence).

Lesson structure (30 minutes)

1. 0–4 min · Visual hook. Teacher shows a short slide sequence of filtration in action (e.g. coffee filter, aquarium water, separating sand from water) with labelled parts of a filter setup. Students do a quick think-pair-share: “What stays? What moves through?”

2. 4–9 min · Direct teach (model steps). Teacher displays a “Filtration steps” diagram slide-by-slide and says: 1) set up filter, 2) place mixture carefully, 3) observe liquid flow, 4) collect filtrate, 5) observe residue. Students mark the steps on mini task cards (1–5) to practise ordering.

3. 9–16 min · Modelled filtering demonstration. Teacher demonstrates filtration of a cloudy mixture (e.g. sand/soil in water) using a funnel, filter paper, and collection cup. Teacher pauses at key moments (before pouring, after pouring starts, when filtration finishes) and asks: “Which part is the filtrate? Which part is the residue?” Students record two observations in their workbook: (a) colour/clarity of filtrate, (b) what remains on filter paper.

4. 16–21 min · Guided group analysis. In groups of 3–4, students compare their observations to a provided “results table” slide (predicted vs observed). Each group answers multiple-choice questions on a sheet:

• What is the filtrate?
• Why does the mixture separate?
• Which particle size is more likely to pass through? Teacher circulates and checks reasoning, prompting students to use words like “retained”, “passes through”, “filter paper”.

5. 21–26 min · Independent worksheet (multiple choice, then justify). Students complete a multiple-choice worksheet titled “Filtration Explained”:

• Q1–Q4: order and identify parts of filtration.
• Q5–Q8: choose correct uses of filtration and match the use to what filtration removes.
• Last question: one sentence choice from sentence starters (e.g. “Filtration works because…”). Teacher collects or spot-checks.

6. 26–30 min · Video wrap + exit check. Teacher plays the YouTube clip “How Filtration Works” (no pausing unless needed for behaviour). After the clip, students answer one final multiple-choice question on a slip: “In filtration, the liquid is called the ___.” Teacher quickly reviews answers and thanks students.

Resources

• Slide deck with labelled filtration diagram and real-life examples (coffee filter, water cleaning)
• Demonstration materials: funnel, filter paper, beakers/cups, sand/soil-water mixture
• Safety items: gloves and eye protection (as needed), paper towels, waste container
• Teacher observation sheet or board template for filtrate/residue notes
• Group “results table” slide and group multiple-choice analysis sheet
• Individual multiple-choice worksheet “Filtration Explained” (including a short sentence starter item)
• Timer visible to students
• YouTube clip “How Filtration Works” (prepared in advance, sound tested)

Assessment

• Formative: observe student ordering of filtration steps during the direct teach segment.
• Formative: check group multiple-choice reasoning about filtrate/residue and why separation occurs.
• Formative: collect exit slip (filtrate term) and review worksheet misconceptions (e.g. confusing residue with filtrate).

Differentiation

• Autistic students support: provide the steps visually on slides and on the worksheet; use consistent wording (“passes through”, “retained”) and repeat during transitions.
• Provide sentence starters for the final justification question (multiple-choice + short written response option).
• Offer a “checklist” version of the worksheet for students who need extra structure (same multiple-choice items, with space to tick).
• Extension (for early finishers, within same worksheet set): ask them to circle the most important step and write a single-word reason (e.g. “filter”, “pore size”, “particle size”).
• Manage sensory load during video: low volume option and seating where students are comfortable; allow brief movement break if needed before the clip.

Success criteria for this lesson (repeat for students on the board)

• I can describe the filtration steps in order.
• I can explain what happens to the liquid (filtrate) and solid (residue).
• I can connect filtration to real-life uses based on substance properties.