OpenStem

@openstem · Joined Jul 2026

7420 public items8 groups

Note~279 words · 1 min

Machines that notice things A sensor detects something in the world (light, temperature, sound, motion) and turns it into information a machine can act on. It's how a machine notices anything at all. The sense, compare, act loop Set a therm

Engineering

Engineering · L2 · Sensors & Simple Feedback

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Note~175 words · 1 min

Some projects are too big for one person Think about a playground or a big bridge. The shape, the safety, the materials: there's far too much for one engineer to work out alone. So engineers work in teams, each person taking a different par

Engineering

Engineering · L1 · Building Together: Teams of Engineers

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Note~149 words · 1 min

A prototype is a first try It's a small, cheap, quick model built to test an idea before anyone spends real time and money on the finished thing. Testing a paper aeroplane is far easier than testing a real one. If it flies badly you fold an

Engineering

Engineering · L1 · Prototypes: Try Small Before You Try Big

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Note~230 words · 1 min

Why rolling beats sliding Drag a heavy box across the floor and it scrapes and catches. That scraping is friction, fighting your push. Put the box on a wagon and it rolls almost by itself. The wheel-and-axle A wheel isn't only for rolling.

Engineering

Engineering · L1 · Wheels & Axles: Rolling and Turning Made Easy

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Note~223 words · 1 min

What a ramp does A ramp (an inclined plane) is a flat sloped surface from low to high. Instead of lifting something straight up, you push it up the slope. A wheelchair ramp, a playground slide and a loading ramp on a truck are all doing the

Engineering

Engineering · L1 · Ramps & Wedges: Sloped Simple Machines

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Note~184 words · 1 min

Two kinds of material Electricity needs a path, just like water needs a pipe. Why wires have two layers Look closely at any electrical cord. Inside is thin metal wire, a conductor, carrying the electricity. Wrapped round it is rubber or pla

Engineering

Engineering · L1 · Conductors and Insulators

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Note~188 words · 1 min

What a magnet does A magnet pulls certain metals toward it without touching them. That invisible pull is magnetism, and every magnet has two ends called poles: north and south. Only some metals Magnets at work A fridge magnet sticks because

Engineering

Engineering · L1 · Magnets: Push, Pull, and Everyday Uses

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Note~232 words · 1 min

Air is real stuff You can't see it, but air is made of tiny gas particles that take up space, just like water or sand. Trap it somewhere it can't escape, squeeze, and it pushes back. Try it Air as a cushion A bike tyre isn't solid rubber, i

Engineering

Engineering · L1 · Air Takes Up Space and Pushes Back

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Note~197 words · 1 min

Wind is moving air You can't see air, but when it moves fast enough you can feel it push. That push is strong enough to move real things. Why a pinwheel spins instead of flying off Its blades are set at an ANGLE, not flat. When wind hits an

Engineering

Engineering · L1 · Wind & Sails

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Note~348 words · 2 min

Pressure is what pushes fluid along Water doesn't move through a pipe by itself. Pressure pushes it: how hard the fluid presses on the walls and on anything in its way. Height makes pressure for free A tank up high presses harder at its bot

Engineering

Engineering · L2 · Pressure & Fluids in Pipes

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Note~387 words · 2 min

Heat always moves hot to cold If there's a temperature difference, heat flows: out of a hot tea into the room, out of a warm house into the winter. The trick is trapped air Foam, fibreglass, wool, feathers: they all work the same way. Each

Engineering

Engineering · L2 · Heat Transfer & Insulation

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Note~157 words · 1 min

Why count the cost first? Before engineers start building, they add up what all the parts will cost. That way they know the total in advance and don't run out of money halfway through. You can do exactly the same for a school project. A car

Engineering

Engineering · L1 · Counting the Cost of a Project

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Note~200 words · 1 min

Why keep one When you build and test things you try a lot of ideas, and the details fade within days. A design notebook is where you write and sketch what you tried and what happened, so nothing gets lost. It doesn't need to be fancy. Any n

Engineering

Engineering · L1 · Keeping a Design Notebook

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Note~236 words · 1 min

A lever is a bar that tips Just a stiff bar or board that pivots around a fixed point. Push one end down and the other swings up. That fixed point is the fulcrum, and where it sits controls everything about how the lever behaves. Balancing

Engineering

Engineering · L1 · Levers & Seesaws: Pivoting Your Way to a Big Lift

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Note~256 words · 1 min

A gear is a wheel with teeth Plain wheels are smooth and can slip against each other. A gear's teeth grip, so it never slips. That makes gears perfect for passing turning motion from one part of a machine to another. When the teeth of two g

Engineering

Engineering · L1 · How Gears Turn Each Other

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Note~220 words · 1 min

Electricity in, light out A bulb has one job: turn electricity into light. Flip the switch, electricity flows, the bulb glows. No electricity, no light. Two ways to glow Inside an old bulb is a filament: a wire so thin that electricity stru

Engineering

Engineering · L1 · How a Bulb Turns Electricity Into Light

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Note~193 words · 1 min

Electricity to sound A buzzer and a speaker do the same basic job. Give one power and a tiny part inside starts moving very fast. That fast movement is vibration, and it's how electricity becomes something you can hear. What vibration is A

Engineering

Engineering · L1 · How Electricity Makes Sound

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Note~250 words · 1 min

Warm air floats Watch a hot air balloon. A burner roars underneath, filling it with heated air, and the whole thing lifts off the ground. Nothing pushed it up. Why it rises Heated air spreads out and becomes less crowded than the cool air a

Engineering

Engineering · L1 · Hot Air Rises

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Note~248 words · 1 min

Water turning into a gas Heat a pot of water and at first it just gets warmer. Keep going and bubbles rush to the surface: it's boiling, turning into steam, which is water as a GAS instead of a liquid. Why a kettle whistles A kettle spout h

Engineering

Engineering · L1 · Water Turning to Steam

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Note~207 words · 1 min

What a trade-off is Getting more of one good thing means getting less of another. Engineers run into this constantly; almost every design choice has one. Think about a backpack. A bigger one holds more, which is great. It's also heavier to

Engineering

Engineering · L1 · Trade-Offs: More of One, Less of Another

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Note~138 words · 1 min

It's a loop, not a line Nobody gets it right first time. The cycle assumes that. The two habits that separate engineering from guessing

Engineering

Engineering · L2 · The Engineering Design Cycle

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Note~252 words · 1 min

Draw it before you build it Before a brick is laid or metal is cut, engineers draw a plan. It lets the engineer, the builder and the client agree on exact size and shape while changes are still cheap. One picture isn't enough Draw a mug fro

Engineering

Engineering · L2 · Engineering Drawing & Scale

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Note~263 words · 1 min

Three ways to shape a material Everything you own started as raw material: plastic pellets, a block of metal, a sheet of wood. The process that shaped it depends on the material and how many copies were needed. Moulding and casting Injectio

Engineering

Engineering · L2 · How Things Are Made: Molding, Casting, and Cutting

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Note~225 words · 1 min

Driving gear, driven gear Always count teeth. It's exact, and a ruler isn't. What the number does Gear trains and the idler Where you meet gear ratios

Engineering

Engineering · L2 · Calculating Gear Ratios

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Note~178 words · 1 min

Every lever has the same three parts The class is decided by one question: which of the three sits in the MIDDLE? Class 1: fulcrum in the middle Class 2: load in the middle Class 3: effort in the middle

Engineering

Engineering · L2 · Levers: Three Classes

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Note~284 words · 1 min

A shape that only ever squeezes Where the load goes Thick walls, buttresses or solid ground do that job. Ignore thrust and the arch pushes its own supports apart. The keystone A dome is an arch, spun Rotate an arch a full turn around a vert

Engineering

Engineering · L2 · Arches & Domes

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Note~223 words · 1 min

Two ways to connect them, two different results One battery supplies only so much voltage, and only for so long. Connecting several helps, but HOW you connect them decides which of those two problems you solve. Series adds voltage Two 1.5 V

Engineering

Engineering · L2 · Combining Batteries: Series vs Parallel

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Note~282 words · 1 min

Three parts, one loop A robot combines sensors to sense, a program to decide, and motors to act. None of the three is a robot by itself. A line-following robot One light sensor pointed at the floor, a small computer, two wheel motors. That'

Engineering

Engineering · L2 · What Makes a Robot a Robot

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Note~269 words · 1 min

Liquids that refuse to mix Pour honey, dish soap, water and vegetable oil into one tall glass and they don't blend into a murky mess. They settle into four clean layers. Density decides the order: how much mass is packed into a given volume

Engineering

Engineering · L2 · Density Layers in Liquids

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Note~240 words · 1 min

Power that doesn't run out Three ways to make electricity from nature Where to build each one Site selection is engineering in its own right. The best turbine in the world makes almost nothing standing somewhere sheltered, and a perfect pan

Engineering

Engineering · L2 · Renewable Energy Basics

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