ACARA v9 CONTENT DESCRIPTION “consider how people use scientific explanations to meet a need or solve a problem”
Builds on noticing how the world works. Now we look at why people bother to find those things out. When you know a science idea, like the way friction slows a sliding load, you can use it to meet a need or solve a problem in everyday life.
A science idea can solve a real problem
Science is not just for the classroom. Every day people use what they have learned about the world to make life easier. People worked out that friction is the force that fights a sliding box and slows it down, and that a rolling wheel meets the ground with far less friction than a box being dragged. That one idea leads to a clever solution: to move a heavy load without wearing yourself out, do not drag it. Stand it on wheels so it rolls. From that thought comes the wheeled trolley you see in every shop and warehouse.
From the friction idea to a wheeled trolley
Add each new idea in turn and watch how knowing how friction works leads people to build something that moves a heavy load.
New evidence (1 of 4)
People notice that a heavy box is hard to drag across the floor, and that it scrapes and slows the moment they push.
Accepted model: The need: move a heavy load across the room without straining to drag it the whole way.
Add the next piece of evidence and watch whether the accepted model holds or has to change.
Choosing between solutions
Often there is more than one way to solve a problem, and each way has good points and not so good points. Imagine you must move a heavy crate to the far side of a workshop, and up onto a loading shelf. You could drag it across the floor, roll it on a trolley, or push it up a ramp. Each way uses the friction idea in its own manner, but each also gives up something. People weigh these trade-offs and pick the solution that fits the need best.
Pick a way to move the heavy crate
You know that friction fights a sliding load, that wheels roll with far less friction, and that a smooth surface drags less than a rough one. Choose a way and see what you gain and what you give up.
You need to move a heavy crate across a workshop and up onto a shelf. You know friction slows a dragged box, that wheels roll with much less friction, and that a smooth ramp lets a load rise gently. Which way will you choose?
Choose a response to see what is gained and what is given up.
Which choices really use the friction idea?
A removal team wants to move a heavy cabinet out of a house. They know a science idea: friction fights a sliding load, and rolling or a smooth surface lowers that friction. Some of the choices below use that idea to solve the problem, and some are just about how things look. Sort each one into whether it really uses the science explanation about friction.
Does the choice use the friction idea to move the load?
The science idea: friction fights a sliding load, and rolling or a smooth surface lowers it. Decide which choices use that idea to move the heavy cabinet.
Claim: Knowing about friction helps the team move the heavy cabinet with less effort.
They tip the cabinet onto a wheeled dolly so it rolls instead of being dragged.
They lay a smooth sheet of board over the rough doorstep so the load slides across it more easily.
They pick the truck because its paint matches the company sign.
They put the cabinet on rollers, so it turns on round logs that roll along the path.
They choose a cabinet cover because it has a pattern they like the look of.
Decide whether each statement is evidence for the claim, or not.
Why this matters
The wheeled trolley, the smooth ramp and the rolling dolly all started as a science idea about how the world works. People learned how friction slows a sliding load and how rolling and smooth surfaces lower it, and then they used those explanations to meet a need and solve a problem. Once you see this, you notice science all around you, quietly making everyday work easier.
Quick self-check
1. People worked out that friction slows a sliding box, and that rolling has much less friction than sliding. How does that science idea help solve a problem?
2. A worker needs to move a heavy load across a rough wooden floor. Which choice uses the science idea that a smooth surface has less friction?
3. Which of these is using a science explanation to meet a need?
4. When people pick a way to move a heavy load, why is there often more than one good choice?