Science 6 - Lesson 3.4.3

Machines

Lesson 3.4.3
November 4, 2024

​Lesson Overview

Learners can:

• explain how machines help us do work

• define efficiency and state how it is calculated

• define mechanical advantage and state how it is calculated

Vocabulary

• efficiency: ratio of work being done by a machine to the work needed to operate the machine

• machine: a device that makes work easier

• mechanical advantage: amount a machine multiplies the input force

When you turn a doorknob, the knob turns a greater distance than the latch. The knob increases the force on the latch.

Increasing Force

When using a machine that increased distance, the output force is less than the input force. Like the bottom of a paddle traveling farther than the handle.

Increasing Distance

Some machines, like pulleys, change the direction of the force, but there is no change between input and output force.

​​Changing Direction