MYP 3, Integrated Science
Unit #1: How do we make it work? (Energy, Work & Simple Machines)
Exploration: Levers & Moments
Introduction - A lever is a simple machine. It is a board/bar that pivots on a fulcrum. It
makes it easier to lift and lower objects by changing the direction of the force and even
reducing the effort force at times.
The turning effect of the different forces around the fulcrum is call the moment. It can be
calculated by: Moment (N m) = Force (N) X distance from fulcrum (m)
Exploration – You will be playing with weights on a lever to understand balancing
moments, force magnifiers and distance magnifiers.
Part 1: Balance & Force Magnifier
Materials Provided:


A meter stick
A fulcrum such as an eraser or a pencil taped to the table
Procedure:
1. Place the meter stick on the fulcrum so it is equally balanced.
2. Place the weights at different locations on either side of the lever as per the table below
until the lever is balanced.
3. Make note of the distances from the fulcrum and and calculate the moments in the table
below.
Observation:
Weight on
one side
(Effort)
50 gm
(0.5 N)
Distance
from center
(m)
Calculate
Moment (N
m)
Weight on
one side
(Load)
50 gm
(0.5 N)
100 gm
(1 N)
150 gm
(1.5 N)
Other
Distance
from center
(m)
Calculate
Moment (N
m)
What happens to the side of the load weight IF the effort weight is placed further away from
the fulcrum after you balanced the levers? Try it!
1
Conclusions: Do you see the pattern in the table and can you deduce a rule for balancing
weights on a lever? Can a lever lift a load force with less effort force (force magnifier)? If
yes, where do you place the effort force for this to happen?
Part 2: Distance Magnifier
Materials Provided: A smaller (e.g. 30 cm) ruler
Procedure:
1. Place the fulcrum (eraser or pencil) 10cm from one end of the 30 cm ruler
2. Place a small piece of balled up paper on the end furthest from the fulcrum
3. Press down/tap on the opposite end of the ruler.
Observation:
Conclusions: Based on your observations, how would you define a distance magnifier lever? For
distance magnifier levers, where should the fulcrum be in reference to the load force?
2