Example presentation · School
Photosynthesis
What the presentation covers
Slide 1 Photosynthesis: How Plants Eat Sunlight
Life Science · Middle School · Every meal you have ever eaten started with a plant and the sun. · Big question for today · How does a leaf make sugar out of light, air and water?
Slide 2 What Is Photosynthesis?
The Big Idea · PHOTO = light · SYNTHESIS = making something · Plants use light energy to build their own food: glucose, a sugar. · They take in carbon dioxide from the air and water from the soil. · Leftover oxygen is released — the air we breathe. · Plants are producers: they make food instead of eating it.
Slide 3 The Recipe: Four Ingredients
What a Plant Needs · Sunlight · The energy that powers the whole process. · Water (H2O) · Absorbed by the roots, travels up the stem. · Carbon dioxide (CO2) · Enters through tiny pores in leaves called stomata. · Chlorophyll
Slide 4 The Equation
Write It Like a Scientist · Reactants — left · Products — right · light energy · 6 carbon dioxide · 6 water · 1 glucose · 6 oxygen
Slide 5 Inside the Leaf: The Chloroplast
Where It Happens · Leaf layers: cuticle (waxy shield), upper skin, the spongy middle, lower skin with stomata. · Chloroplasts: tiny green disks inside leaf cells — the food factories. · Chlorophyll absorbs red and blue light and reflects green — that is why leaves look green. · One leaf cell can hold dozens of chloroplasts.
Slide 6 Two Stages, One Factory
How the Process Works · Stage 1 · In the Light · Chlorophyll captures light — the green pigment in leaves gets to work. · Splits water molecules taken up by the roots. · Releases oxygen — the gas we breathe, out through the leaf. · Energy stored · Stage 2
Slide 7 Why Photosynthesis Matters to YOU
The Payoff · Every breath · Plants and algae make nearly all the oxygen in the air you breathe. · Every meal · Bread, rice, fruit — and even meat — all trace back to plants making glucose. · Fossil fuels · Coal, oil and gas are stored ancient photosynthesis from millions of years ago. · Food chains
Slide 8 Try It at Home: The Leaf in a Jar
Mini Experiment · Put a fresh water plant (like elodea) in a clear jar of water in sunlight. · Watch: tiny bubbles appear on the leaves — that is oxygen being released. · More light = more bubbles: the rate of photosynthesis follows the light. · Move the jar to shade and compare the bubble count. · Record it · Count bubbles for one minute in sunlight, then again in shade — write both numbers down and compare. · Safety
Slide 9 Check Yourself
Quick Quiz · Five questions — answer out loud, then compare with a partner. · What gas do plants take IN during photosynthesis? · What gas do they give OUT? · Where in the cell does photosynthesis happen? · Complete the equation: 6CO₂ + 6H₂O + light → ? · Why do most leaves look green? · Answers with your teacher
Slide 10 One Leaf, One Planet
6 CO₂ + 6 H₂O + light → C₆H₁₂O₆ + 6 O₂ · Every green leaf is a solar-powered food factory — running right now. · It feeds · Glucose made from light, water and carbon dioxide feeds plants — and feeds animals too. · It breathes · Photosynthesis fills the sky with breathable oxygen, one leaf at a time. · Look up · Look at a tree today and see the chemistry happening in front of you.