Science Experiments / Week 5
Week 5 of 6
Simple Machines, Structures, and Stability
Big question
How can simple tools and smart shapes help us do hard jobs?
- Mini Machine or Tower Challenge (pick one)
- 50-60 minutes
This week follows the science loop
AskPredictTestObserveExplainImprove
The big idea
- Simple machines make work easier.
- Ramps, levers, wheels, and pulleys help us move or lift things.
- Structures are stronger when they have a stable base and use support shapes like triangles.
- Good designs are tested and then improved.
A simple machine is a simple tool that makes a hard job easier - like a ramp, a lever, a wheel, or a pulley. A lever, for example, is a stiff bar that turns on a resting point, and it lets a small push lift a heavy load. Structures like towers and bridges have a different job: they have to hold weight without falling. A wide base keeps a structure from tipping, and triangles are the secret shape that keeps it from bending. This week you choose your challenge: build a simple machine that lifts a weight, or build a structure that stands tall and strong. Either way, you will test it and then make it better.
Words to know
- Simple machine
- A simple tool that makes work easier, like a lever or a ramp.
- Lever
- A stiff bar that turns on a resting point to lift or move a load.
- Pulley
- A wheel with a rope over it that helps lift things.
- Structure
- Something built to hold weight or stand up, like a tower or bridge.
- Stable
- Steady and hard to tip over.
- Brace
- A support, often a triangle shape, that stops a structure from bending.
Materials
- For a machine: a ruler and a pencil for a lever, or a spool and string for a pulley
- Small weights to lift, like a stack of coins or a small toy
- For a structure: index cards, straws, or craft sticks
- Tape
- A ruler
- Coins or washers to test how much weight it holds
Safety
- Keep fingers out from under levers and weights when they drop.
- Keep test weights small and low so nothing heavy falls on anyone.
- Cut and pass scissors safely, point down.
Experiment: Mini Machine or Tower Challenge (pick one)
Predict first
Before you touch any materials, write down what you think will happen in this experiment - and why. Making a prediction first is what turns building into science. You will compare your prediction to what you actually observe.
Steps
- 1
Ask: How can a simple machine or a strong shape help me lift or hold more? Pick the machine path or the tower path.
- 2
Machine path: Lay a ruler across a pencil to make a lever. Put a small weight on one end.
- 3
Tower path: Build the tallest tower you can from cards or straws and tape that can still hold a weight on top.
- 4
Predict: For the lever, guess where to put the pencil to lift the weight most easily. For the tower, guess how many coins it will hold. Write it down.
- 5
Test: For the lever, press the other end and slide the pencil to different spots. For the tower, add coins one at a time until it bends or tips.
- 6
Observe: Notice which pencil position made lifting easiest, or how many coins the tower held before it failed.
- 7
Improve: Move the pencil closer to the weight, or add triangle braces and a wider base to the tower, then test again.
Why it happens
A lever turns on its resting point, called a fulcrum. When you move the fulcrum closer to the load, a small push on the far end can lift a big weight - the machine trades a longer push for an easier one. Structures work differently: a wide base spreads the weight out and lowers the chance of tipping, and triangles keep their shape under weight while squares fold and bend. That is why braced, wide-based towers hold so much more.
How engineers use this
Engineers build these ideas into real life every day: seesaws and bottle openers are levers, cranes and flagpoles use pulleys, wheelchair ramps are inclined planes, and bridges and skyscrapers are braced with triangles and wide bases. And like you, engineers always test a design and then improve it.
What did you notice?
Look back at your prediction and your results, then talk these through together.
- What made lifting the weight easier, or what made the tower stronger?
- Why do you think triangles hold up better than squares?
- Where does a wide base help something stay standing?
- What simple machines have you used today without noticing?
Reflect
Draw your machine or tower and label the part that did the most work to make the job easier.
Mini challenge
Machine path: lift the heaviest weight you can with your lever. Tower path: build the tower that holds the most coins.
Want to go further?
Add a second simple machine - like a pulley to lift your load - or combine a ramp and a lever to move something.
Before you finish
- I built a simple machine or a structure.
- I made a prediction before testing it.
- I tested how much it could lift or hold.
- I can explain how a lever, or a wide base and triangles, made the job easier.
- I improved my design and tested it again.
Finished the experiment and your reflection? Mark this week complete to track your progress through the 6-week course.
Lab journal
Write your own science notes as you go - they follow the same loop you used this week. Notes are saved on this device only; nothing is sent anywhere. You can also print this lesson and write by hand.
What did you want to find out?
What did you think would happen, and why?
What one thing did you change to keep it a fair test?
What did you see, hear, or measure?
Use what you noticed as your evidence.
What would you change to make it work better?
Draw what happened
Sketch your experiment or your improved design, and circle the part you changed.