Forces

Forces

Forces: Objectives

- I can describe a force.

- I know the unit of measurement for force.

- I know the difference between mass and weight.

- I understand the 4 universal forces.

Forces

Forces are created and applied every time anything moves. Forces such as weight are even present when things are not moving. Your body uses forces every moment of your life, for every action, from the beating of your heart to walking up stairs. Understanding how forces are created and described is fundamental to understanding nature.

Multiple Choice

Forces are only present when things are moving.

• True

• False

A Force is a push...

...or a pull

...or any action that has the ability to change motion.​

Open Ended

Can you think of a specific example of a type of force?

Force is an action! You need force to start things moving, and to make any change to an objects motion.

Forces can increase or decrease the speed of an object.

Forces can also change the direction in which an object is moving.

A force can start movement.

In this example, a force is being applied to a golf ball sitting still, to start movement.

A force can also stop a moving object.

In this example, a force is being applied to the moving ball to stop it.

A force also changes the direction of an object.

In this example, wind is affecting the direction the soccer ball is traveling in, causing it to spin and turn and change direction.

Newton - a unit that measures force.

The newton is defined by how much force can change the motion of an object.

Multiple Choice

Friction is a force.

• True

• False

There are 4 Universal Forces

1. Strong Nuclear Force

2. Electromagnetic Force

3. Weak Nuclear Force

4. Gravity

(listed from strongest to weakest)

The nucleus of an atom is made of protons, which all have a positive charge. But similar charges repel each other. Positive pushes away positive and negative pushes away negative.

So what stops the atoms from flying apart and every atom and molecule in your body exploding into smithereens'!?!?!

​1. Strong Nuclear Force

​

The strong nuclear force does. It’s basically the glue that holds nucleus together, but it only works over very, very small distances.

2. Electromagnetic Force

This is what light is made of. No, really. I promise. And it is one million million million million million million times stronger than gravity. Seriously. Don’t believe me? Tell that to your sunburn this summer. The energy from electromagnetic forces that gives you a sunburn (UV Rays) travels millions of miles just to burn you. That's a strong force.

2. Electromagnetic Force

You don’t feel the sun’s gravity pulling on you as it moves through the sky, but you definitely feel light blistering your skin.

​

This force comes in waves, and emits light (visible and invisible).

2. Electromagnetic Force

The electromagnetic force is also responsible for what holds electrons in an orbit around an atom as the negatively charged electron orbits around the positively charged nucleus.

3. Weak nuclear force

The weak force is a force that leads to some kinds of radioactivity, as seen by the neutrons and protons leaving the atom.

​

Radioactivity is when ​an atom is unstable and loses some of its energetic particles.

4. Gravity

The one we might think is the strongest, is actually the weakest. But the more stuff you have (the more mass) the stronger gravity becomes, and the Earth is made of a LOT of stuff, so the gravitational pull of the Earth feels very strong indeed.

4. Gravity

​

The universal force of attraction acting between all matter.

Earth's gravity creates a force called weight that pulls on everything around you.

Weight is a force that comes from gravity pulling down on any object with mass. The more the mass, the greater the gravity.

Open Ended

What do you think the difference between mass and weight is?

The difference between mass and weight is that weight is a force that involves gravity.​

​

MASS IS NOT A FORCE!

​

weight (W) = mass (m) X gravity (g)

This is why your weight on Mars is less than on Earth.

Even though your mass is the same on Earth and Mars, the gravitational pull on you is different.

​

Mars has less of a pull on you because it has less mass than Earth.​

Multiple Choice

This type of force is responsible for holding atoms together at their nucleus.

• Strong nuclear

• Weak nuclear force

• Gravity

• Electromagnetic

Multiple Choice

This type of force is responsible for planets orbiting.

• Strong nuclear

• Weak nuclear force

• Gravity

• Electromagnetic

Multiple Choice

This type of force is responsible for the light you see.

• Strong nuclear

• Weak nuclear force

• Gravity

• Electromagnetic

Multiple Choice

This type of force is responsible for The Hulk's superpowers.

• Strong nuclear

• Weak nuclear force

• Gravity

• Electromagnetic

To sum up the 4 Universal Forces...

Strong Force

Gravitational Force

Weak Force

Electromagnetic Force

holds protons and neutrons together in the nucleus.​

force between all objects that contain with mass.

responsible for radioactivity.

holds electrons ​in orbit around an atom, travels in waves through space.