Structures
Simple Machines 1
Simple Machines 2
Complex Machines
100
What is a structure?
A structure is a group of elements that can support weight and can protect the objects or machines it is made for.
100
What are the six simple machines?
The six simple machines are the lever, wheel, inclined plane, screw, wedge, and pulley.
100
Why do we use simple machines?
Simple machines help us to perform tasks or reduce the force.
100
A complex machine is a machine made of:
a) one simple machine
b) two or more simple machines
b) A complex machine is a machine made of two or more simple machines
200
Structures can be classified as ______ structures and ______ structures.
Structures can be classified as natural structures and artificial structures.
200
Which simple machine has a fulcrum (Fu), a load (L), and a force (F)?
Clue: for example, a see-saw.
A lever has a fulcrum (Fu), a load (L), and a force (F).
200
There are three types of levers: first-class lever, second-class lever, and third-class lever.
What type of lever are scissors? Why?
Scissors are a first-class lever because the fulcrum is in the middle.
200
Which of is not a complex machine?
a) cog
b) rack and pinion
c) crank
d) pulley 
e) cogs and chain
d) pulley
(Remember: a pulley is a simple machine)
300
Colin's skeleton and a tree are examples of what kind of structures?
Colin's skeleton and a tree are natural structures.
300
Which simple machine is a circular object that rolls around a central axis?
Clue: for example, a tire.
A wheel is a circular object that rolls around a central axis.
300
There are three types of levers: first-class lever, second-class lever, and third-class lever.
Which type of lever is elbow lifting? Why?
An elbow lifting is a third-class lever because the force is in the middle.
300
A bicycle is a complex machine. Why?
A bicycle is a complex machine because it is made of many simple machines.
400
A bridge, a swing, and a house are examples of what kind of structure?
A bridge, a swing, and a house are artificial structures.
400
Which simple machine is an incline plane wrapped around a cylinder?
Clue: for example, the top of a box of orange juice.
A screw is an inclined plane wrapped around a cylinder.
400
What type of lever is a wheelbarrow? Why?
A wheelbarrow is a second-class lever because the load is in the middle.
400
A cork screw is an example of a complex machine.
1) What is the name of this complex machine?
2) Which simple machines does it have?
a) This is a rack and pinion
b) This machine has levers and a screw.
500
True or False:
Artificial structures are groups of elements that can support weight and protect the objects they are made for. Some examples of artificial structures are houses, schools, trees, bridges and shelves.
FALSE.
A tree is not an artificial structure. It is a natural structure.
500
1) Which simple machine is made of two inclined planes together?
Clue: for example, an axe.
2) Which simple machine is made of a wheel and rope?
Clue: for example, a well.
1) A wedge is made of two inclined planes together
2) A pulley is made of a wheel and rope.
500
I need to bring very, very heavy dirt (tierra) to a high place. I do not have a rope or wheel. Which simple machine should I use to lessen the force?
You should use an inclined plane.
(Remember: an inclined plane is used to raise and lower objects with less force.)
500
When we have two cogs together, they move in opposite directions.
If we have three cogs together, the third cog will move...
a) in the same direction as the first
b) in the opposite direction as the first
If we have three cogs together, the third cog will move (a) in the same direction as the first.
LOOK! The 3rd cog moves in the same direction as the 1st.
