The four forces of nature

1. The four forces of nature Gravity, electromagnetism, Strong nuclear, and weak nuclear Presented By: Brittany Kach and Julia Angotti

2. Gravity • Gravity is the force that pulls all objects in the universe towards each other. • It is responsible for pulling you, me, and everything else on Earth towards the center of the planet. • Newton witnessed gravity when he saw an apple falling to the ground. • Everything on Earth falls with a velocity of 9.8 m/s squared. • No matter the mass of the object, it will always fall at that speed if it’s on Earth.

3. Gravity • Newton also realized that the force responsible for pulling objects to the ground is the same one responsible for planetary orbit. • Einstein also agreed with this but changed how we looked at it. • He thought of gravity in space as a space-time fabric, in which everything in the universe rests on. • The bigger mass an object has, the larger the warp in space-time. • The warps in the fabric of causes planets to orbit.

4. Gravity • Take something that has a large mass, for example, our sun. • Our sun would create a large dip in the space-time fabric. • Our Earth and all the other planets in our solar system orbit around the warps the sun makes in the fabric. • The wider the dip the object is going around, the longer it takes to complete an orbit. • This is also how satellites orbit around Earth.

5. Electromagnetism • Electromagnetism is the force that does many things. • Lightning is an example of electromagnetism in nature. • During a storm, the magnetic field around the Earth is optimized. • The build-up of electricity in the clouds charges with the magnetic field. • Whenever the charge gets big enough, it is released in a bolt of energy. • This is what lightning is.

6. Electromagnetism • You might wonder why, if gravity pulls us toward the center of the Earth, that we don’t just get pulled straight through the ground. • Well, electromagnetism is stronger than gravity and repels it. • Electromagnetisms is also in atoms. • Our atoms collide with the atoms in the ground. • Electromagnetism acts like a barrier between our atoms being pulled towards the Earth and the atoms of the surface of the Earth. Gravity Electromagnetism

7. Electromagnetism • As stated before, electromagnetism is also found in atoms. • It is the force that keeps the negatively charged electrons in orbit around the nucleus of an atom. • It is a perfect example of electricity and magnetism. • The magnetism aspect is the electrons, which get negatively charged. • The electricity keeps it in orbit around the neutral neutrons and the positively charged electrons. • It creates the harmony of balanced charges throughout the entire atom.

8. Strong Nuclear • Strong Nuclear Force is found at the very center of the atoms. • It acts like a subatomic super glue. • This force binds the protons and neutrons together to form the nucleus of an atom. • The force binding them together is hundreds of times stronger than our force of gravity. • It is slim to nearly impossible to break apart the nucleus. • But, when it does happen, it creates a huge catastrophe.

9. Strong Nuclear • The Strong Nuclear Force is also the cause for the devastating Nuclear Bomb. • When an atom gets unstable enough, the nucleus does break apart. • All the energy stored up from holding the nucleus together is released as a huge explosion. • This explosion completely incinerates anything it comes across, including whole cities. • This bomb is very hazardous and powerful, while all the energy is coming from a single atom.

10. Strong Nuclear • But, how do we harness this power to be activated at a precise moment? • The answer is particle accelerators. • These are long enclosed underground tunnels that are used to upset and atom. • These work by pelting an unstable atom with protons in the tunnel until it starts to break apart. • Then it goes to be transported into the bomb. • When the bomb drops on the targeted area, it causes the atom to become even more upset and completely break apart, causing the explosion we recognize.

11. Weak Nuclear • The weak nuclear force is also found in atoms, but is dormant until the nucleus breaks apart. • When the energy is released from the nucleus tearing apart, it creates a tremendous amount of heat. • With enough heat, certain particles can be fused and changed into another particle. • Weak nuclear force can change the neutral neutrons in the nucleus to positively charged protons. • When this happens, radio- activity is formed as a result. N P

12. Weak Nuclear • Radioactivity is the particles that are emitted when an atom explodes. • There are three types of radiation – alpha particles (which are positively charged), beta particles (which are negatively charged), and gamma rays (which are neutral). • Because it is impossible to predict when an atomic nucleus will emit radioactivity, radioactivity is measured using half-lives, which is the period of time it takes for half the nuclei to decay. • Radioactivity causes superheroes and teenage mutant ninja turtles. • No, just kidding. Radioactivity can weaken and break up DNA, causing the cells to die or mutant in ways that may lead to cancer.

13. Unification