Science lesson plan · 7th grade (Year 8 in England) · 45 minutes
Test foods for starch, sugar, protein and fat
Human body and health
CCSS NGSS.MS-LS1-7CCSS NGSS.SEP 3England: KS3 Biology: Nutrition and digestionEngland: GCSE Combined Science: Organisation (required practical: food tests)
Objective and success criteria
Students will: Test foods for starch, sugar, protein and fat.
- 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: Food groups, nutrients and what each one does
Leads to: the next skill in this area.
Materials: Stopwatches, Body diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Food groups, nutrients and what each one does). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which nutrient group matches this: keeps food moving through the intestines? (lipids (fats and oils) / vitamins and minerals / carbohydrates / fibre (fiber)) → fibre (fiber)Prompt: Energy, growth, stored energy, small amounts for health, or keeping the gut moving?
- A bowl of porridge (oatmeal) contains 32 g of carbohydrate, 5 g of protein and 13 g of fat. Carbohydrate and protein each release 17 kJ per gram; fat releases 37 kJ per gram. How much energy does it provide, in kJ? → 1110 kJPrompt: Work out the energy from each nutrient separately.
- A teenager eats lots of white bread and sweets but few vegetables, and has constipation. What should they add? (more salt / more sugar / more fat / more fibre (fiber)) → more fibre (fiber)Prompt: Which nutrient keeps food moving through the gut?
Hook · 5 min
- Ask everyone to find their pulse, then jump for 30 seconds and find it again.
- Share the objective: Test foods for starch, sugar, protein and fat. 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 food sample gives this result: iodine turns blue-black. Which nutrient is present?
- Step 1: Iodine solution turns from orange-brown to blue-black with starch.
- Step 2: So the answer is: starch
- Answer: starch
- 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 food sample gives this result: ethanol then water gives a cloudy white layer. Which nutrient is present? (starch / sugar (reducing sugar) / protein / fat (lipid)) → fat (lipid)Prompt: Each test is used for just one nutrient.
- A food was tested. Iodine: stays orange-brown. Benedict's (heated): stays blue. Biuret: purple. Which nutrients does it contain? (sugar / starch and sugar and protein / protein / starch and protein) → proteinPrompt: A colour change means the nutrient is present.
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.
- A food was tested. Iodine: blue-black. Benedict's (heated): brick-red. Biuret: stays blue. Which nutrients does it contain? (starch and sugar / starch / protein / sugar) → starch and sugarPrompt: A colour change means the nutrient is present.
- Why must food be ground up and mixed with water before testing? (so the nutrients dissolve and can react with the reagents / to make it taste better / to kill bacteria / to change its colour) → so the nutrients dissolve and can react with the reagentsPrompt: The reagents are solutions.
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: Food groups, nutrients and what each one does.
- Use concrete materials: stopwatches.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- 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-7.
Free lesson plan from eurekami.com/lesson-plan-builder