Presentation on theme: "MACHINES MACHINES MOVE THE WORLD UNIT 3 Marta Vidal Vidal L8 L8 L9 L10 L11L9L10L11."— Presentation transcript:
MACHINES MACHINES MOVE THE WORLD UNIT 3 Marta Vidal Vidal L8 L8 L9 L10 L11L9L10L11
IS A/AN ….. A MACHINE? u CHEESE GRATER SEE-SAW/ AXE
Question Yes, it is a machine. No, it isn’t a machine. BETLOSSGAIN 1. Is a TV a machine? Are scissors a machine? TOTAL: Grand total= Let’s bet! Is a/an ………..a machine? Write questions for all the objects and bet (from 1 to 5). Is a see-saw a machine? Is a well a machine? Is a slide a machine? Is a radio a machine? Is a dog a machine? Is a screw nut a machine? Is a tow truck a machine? Is a book a machine? Is an axe a machine? Is an apple a machine? Is a computer a machine? Is a cheese grater a machine? Is a drier a machine? Is an artichoke a machine? Is a police car a machine? Is a washing machine a machine? Is a telephone a machine? Is a corkscrew a machine?
WHAT IS A MACHINE? It is a device designed to make work easier. IT CAN WORK WITH MECHANICAL ENERGY IT CAN BE COMPLEX OR COMPOUNDIT CAN BE SIMPLE IT CAN WORK WITH ELECTRICITY IT CAN WORK WITH SUN ENERGY IT CAN WORK WITH WIND ENERGY IT CAN WORK WITH CHEMICAL ENERGY
WHAT IS WORK? WORK is done when a FORCE moves something. If you use a PUSH or a PULL to move an object you are doing WORK. PUSH PULL FORCE OBJECT
When we do work we use energy. Law of conservation of energy. “Energy can neither be created (produced) nor destroyed by itself. It can only be transformed.”
HANDS ON! EXERCISE 1 LEVER CAN WE LIFT THIS PENCIL? CAN WE LIFT THIS CHAIR? CAN WE LIFT A CAR?
CAN BOB LIFT THIS BIG ROCK? Let’s see !!
Bob needs a little help He needs a long stick and a small rock
Let’s see ! A big rock Bob Small rock Long stick
Yes, Bob can lift the rock with the help of the stick and the small rock. A STICK + A SMALL ROCK= A SIMPLE MACHINE IT IS CALLED A LEVER A big rock Bob Small rock Long stick LOAD EFFORT LEVER FULCRUM LOAD EFFORT LEVER FULCRUM
At an appropriate distance the big rock moves easily. EASY TO MOVE LOAD EFFORT LEVER FULCRUM
At an inappropriate distance the big rock doesn’t move. DIFFICULT TO MOVE LOAD EFFORT LEVER FULCRUM
HANDS ON! LEVER Ask some questions about the experiment. PROBLEM: Can we do the same work with less effort? How many rulers do we need? What do we do with the rubber? What is the big book for? Which ruler do we use first? What is the ruler for? What are the small books for? We need two rulers: one long and one short. We use the rubber as a fulcrum for doing a lever. We use the big book as a load. Start with the short ruler and then do the same process with the long ruler. We use the ruler as a lever. We use the small books as an effort.
HANDS ON! LEVER MATERIALS Write down the materials that you need to create the lever. -Long ruler -Short ruler -A rubber -A big book -Small books -A pencil
HANDS ON! LEVER STEPS 1. Predict: What is the best position of the rubber (as a fulcrum) to lift the big book with less effort (less small books)? Predict: Which is the best ruler for lift the big book with less effort? 2. Prepare all the materials. 3. Start with the short ruler. 4. Try different positions for the rubber (fulcrum). 5. What is the best position of the rubber (as a fulcrum) to lift the big book with less effort (less small books)? 6. Change the short ruler for the long ruler and repeat the process. 7. What is the best ruler to lift the big book with less effort?
What is the best position of the rubber (as a fulcrum) to lift the big book with less effort (less small books)? Position number 1 Known as
What is the best ruler to lift the big book with less effort? It is the long ruler because it multiplies the effort applied.
LEVER FULCRUM RUBBER EFFORT SMALL BOOKS LOAD BIG BOOK
“Give me a lever long enough; a fulcrum strong enough and I’ll move the world.” Archimedes
LAW OF THE LEVERLEVER “Magnitudes are in equilibrium at distances reciprocally proportional to their weights.” Archimedes Força, Equilibri, Valor i Seny! Force, equilibrium, courage and wisdom!
LEVER It’s a rigid object that is used with an appropriate fulcrum to multiply the effort applied on a load. Fulcrum: a support on which a lever pivots.lever Load: resistance force (weight and gravity). Effort: force needed to move an object. Fulcrum: a support on which a lever pivots.lever Load: resistance force (weight and gravity). Effort: force needed to move an object.
THERE ARE 3 KINDS OF LEVERS
Identify in the pictures: FULCRUM: green dot EFFORT: red arrow LOAD: blue arrow/dot BOTTLE OPENER
Simple machine: LEVER THIRD CLASS LEVER SECOND CLASS LEVER FIRST CLASS LEVER PLIERSSEE-SAW SCISSORS BOTTLE OPENERTONGS SHEARING SCISSORS WHEELBARROWNUTCRAKER TWEEZERS
Other simple machines
INCLINED PLANE It is an inclined surface used to raise an object. It decreases the effort.
WHEEL AND AXLE It is a wheel with a rod, called and axle, through its centre: both parts move together.
SCREW It is an inclined plane wrapped around a central shaft. The Rotational motion of the central shaft causes a linear upwards motion of the screw.Rotational motion screw
PULLEY It is a wheel or set of wheels around which a single rope passes to move a load with a smaller effort.
WEDGE Wedges are moving inclined planes which split or separate a load.
LEVER INCLINED PLANE WHEEL AND AXLE SCREW PULLEY WEDGE TO LIFT OR TO MOVE LOADS THINGS MOVE UP OR DOWN IT TO MOVE LOADS TO HOLD THINGS TOGETHER OR TO LIFT TO MOVE THINGS UP, DOWN OR ACROSS TO CUT OR SPREAD AN OBJECT APART PLIERS SCISSORS HOW IT HELPS US WORK? SIMPLE MACHINES MACHINES
To know more about Simple machinesCompound machines They are any combination of simple machines. Two levers Two wedges SCISSORS
LET’S FIND MACHINES IN OUR SCHOOL PUPILITS NAME WE CAN USE IT TO… WE CAN USE THE……. TO… NAME OF THE SIMPLE MACHINE MARIA JOSEP 1 SCISSORS WE CAN USE THE SCISSORS TO CUT DIFFERENT THINGS LIKE PAPER. 2 LEVERS 2 WEDGES
A COMPOUND MACHINE
OUR SIMPLE LAWN-SPRINKLER A ROCKING CHAIR ( A ) SQUEEZES A BULB ( B ) A CAT CHASES THE MOUSE ( K ) TO RAISE A COVER ( I) EXPOSING A MOUSE ( J ) CAUSING THE ROD ( H ) FALLS HEAVILY INTO THE NET (G ) THIS CAUSES IT TO SHRINK AND PULL THE STRING( D ) THE HOMEMADE BISCUIT ( F ) TIPPING THE SHELF (E) SPRAYING A SHIRT ( C ) THEREBY REVOLVING THE PLATFORM (L) REVOLVES HE IS TICKED ON THE NOSE BY FEATHER BALL ( N ) EACH TIME THE LAUGHING HYENA (M ) CAUSING HIM TO LAUGH SO HARD HE CRIES – THE SPEED OF THE REVOLUTIONS SCATTERS TEARS OVER LAWN CAUSING THE GRASS TO GROW.
Some examples of compound machines Some school projects Different materials Pythagoras switch Advertisements To look at the purpose To look at the materials To look at the idea Amazing !
Step-by-step process to build a compound machine What do you do?Step Choose two partners Choose a theme for the machine Make a drawing/ sketch of a machine Write a list of materials and tools needed. Give your opinion as a group about the process of building the machine. Write the steps of the movement of the different parts of the machine. Make two lists one for the verbs and one for the nouns. Order the different parts of the process. Make the machine. Explain the machine function to other groups. Second Third Fourth Fifth Sixth Seventh Eighth Ninth Finally First Use verbs to describe the action of the parts of the machine. Tenth Phase