Wedges

​Wedges

​Robotics 2023

EXPLANATION

✘ A machine is any object or

mechanical device that
transfers energy from an
input amount of work to an
output amount of work.

✘ The input work and output

work are equal, but the force
applied to the input and
output may not be the same.

✘ Machines can be very

complex or quite simple.

A robot is an
example of a

complex
machine

✘ There are six basic simple

machines. These are mechanical
devices that change the
magnitude or direction of force to
give the user a mechanical
advantage.

✘ This means that less effort will be

required to accomplish the same
amount of work.

✘ The six simple machines are: screw,

inclined plane, wedge, pulley,
lever, and wheel and axle.

Six types of simple machines

Match

Match the following types of pulleys

fixed pulley

movable pulley

compound pulley

Block and tackle

• fixed pulley

• movable pulley

• compound pulley

• Block and tackle

Multiple Choice

How is the mechanical advantage calculated for a pulley system?

• each pulley is added to the system and the reciprocal is used

• the load is divided by the pulling effort

• the pulling effort is divided by the load

Multiple Choice

What are the 6 types of simple machines?

• screw, inclined plane, wedge, pug, lever, wheel and rod

• screw, inclined plane, wedge, pulley, lever, and wheel and rod

• screw, inclined plane, wedge, pulley, lever, and wheel and axle

• screw, inclined plane, wedge, lever, and wheel and rod

✘ A wedge is one of six

classical simple
machines.

✘ It can be used to lift

an object, hold an
object in place, or
separate two objects
or portions of an
object.

And now WEDGES

X

X

X

If you’ve ever propped a door open, chopped
wood, or even eaten with a fork, you have likely

used a wedge. Wedges make our lives easier!

Wedges

Multiple Choice

What is mechanical advantage?

• a description of less effort required to accomplish the same amount of work

• a description of more effort required to accomplish the same amount of work

• a description of no effort required to accomplish the same amount of work

• a description of squirrels using small hand tools

✘ In basic terms, a wedge is two

inclined planes placed back to
back. However, unlike an
inclined plane, a wedge does
not have a right angle.

✘
✘ This machine can be used for a

variety of purposes, including
lifting an object, holding an
object in place, and
separating two objects or
portions of an object.

A wedge has
multiple uses

EXPLANATION

Multiple Choice

In basic terms, a wedge is two inclined planes placed back to back. However, unlike an inclined plane, a wedge does not have __________________________.

• frictionless side

• a wheel

• a right angle

• two angled sides

✘ The mechanical advantage is

calculated based on the ratio
of the length of its slope to
its width.

✘ A short edge with a wide

angle may help you finish a
job faster, but it takes more
force than a longer wedge
with a narrow angle.

The width of

wedges affects
their mechanical

advantage

EXPLANATION

Multiple Choice

Which type of wedge requires more force?

• cheese

• a short wedge with a wide angle

• a longer wedge with a narrow angle

✘ Basically, a wedge is a triangular

shaped tool that’s a portable
version of an inclined plane.

✘ The input force is applied on its

flat, thick surface, and energy is
transported to the sharp end of the wedge.

✘ In this way force is also transported and a

great amount of pressure can be applied
to a thin area to achieve the desired result.

An axe is an
example of a

wedge

EXPLANATION

✘ A wedge can change

the direction of the input
force and apply the force
over a shorter distance.

✘ It has a mechanical

advantage that is greater
than 1.

✘ A longer, thicker wedge

has a greater mechanical
advantage than a
shorter, thinner wedge.

EXPLANATION

Multiple Choice

How is the mechanical advantage calculated for a wedge?

• the length of the slope is divided by its width

• the width is divided by its length of the slope

• the pulling effort is divided by the load

Multiple Choice

Which type of wedge has a greater mechanical advantage?

• cheese

• a short, thinner wedge

• a longer, thicker wedge

✘ The first known example of a

wedge is the hand axe, which has
existed for thousands of years.

✘ Bronze and wood wedges were

used in ancient Egypt to break
away blocks of stone that would

be used in construction projects.

✘ The indigenous people of the

Americas also used wedges
commonly made out of antlers to
help split wood and make canoes,
homes, and other objects.

An axe stone from
the Copper Age,

about 5000
years ago

EXPLANATION

Fill in the Blank

The first known example of a wedge is the ________________________, which has existed for thousands of years.

Multiple Choice

What types of wedges are associated with ancient Egyptians?

• bronze and wood

• bronze and antler

• antler and stone

Multiple Choice

What group of historic people used wedges made of antlers?

• Egyptians

• indigenous American people

• vegetarians

• your dad

QUICK CLIP

What do you observe about the wedge that is being used to cut the wood?

EXPLANATION

✘ Throughout history wedges have been

used to lift heavy objects by separating
them from the surface that they sit on.

✘ For example, if a wedge is slid

underneath a concrete block, less force
is required to lift. The tips of forks and
nails are also considered wedges as
they split and separate the material
that they are pushed into.

✘ Wedges can also be used to separate

objects like blocks of cut stone.

✘ Some wedges are designed to hold

objects in place like engine parts,
doors, and bicycle parts. These work
because of the friction that is
created between the wedge and
the floor or another surface.

✘ Common examples of wedges

include shovels, teeth, certain
screwdrivers, a saw, tacks, a
needle, ice picks, scissors, and push
pins.

✘ All of these wedges are designed to

make work easier to do.

Climber

using an ice

pick as a
wedge

EXPLANATION

Multiple Select

What are common uses of wedges? Select all that apply.

• lifting heavy objects

• reducing friction by being round

• separate objects

• hold objects in place

Multiple Choice

REVIEW:

What is the difference between a wedge and an inclined plane?

• nothing

• the angles between the back and the slope

• one is portable

• only a few letters

Examples

The prongs on a fork are wedges that help

separate your food

✘ Wedges can be

found all around us in
our daily lives.

✘ What examples of

wedges can you
identify around you?

✘ How do wedges

make your life easier?

A nail is an example of a
wedge that splits wood

EXAMPLE VIDEO

Fun Science Demos

How wedges work

Open Ended

Common examples of wedges include:

Open Ended

How can you use wedges in your Sumo robot designs?

Open Ended

2 things you learned about wedges:

Open Ended

1 additional related question you have: