This video gets you started on the right foot. We’ll outline what’s coming up for this unit and how to get the most out of our lesson together. Enjoy!
This video gets you started on the right foot. We’ll outline what’s coming up for this unit and how to get the most out of our lesson together. Enjoy!
Quarks aren’t known to be made out of anything smaller than them. They are elementary particles. Ultimately all particles are made out of energy.
What’s inside a quark
I assume you mean ‘breaks’, as in ‘breaks apart’, not suddenly slows down to a stop, right?
The strong force is transmitted via gluons, which break down at a larger distance (like larger than the radius of a nucleus). If the gluons are no longer holding the quarks together, then you no longer have a proton or neutron.
if gluons hold quarks together and quarks hold protons/neutrons together what happens if a gluon brakes?
From,
Jasmine
8th grade
When a quark in a neutron flips, it does it in a way so that the ‘charge’ is conserved. A down quark has a charge of -1/3, a mass of about 20 times that of the electron, and a downward spin. An up quark has a charge of +2/3 and a mass about 607 times that of the electron. So for a proton that has two ups and one down, the charge is +1. For a neutron with two downs and one up, the charge is zero. We can’t have three down quarks together – the universe just isn’t wired that way. You can read more about it here: http://en.wikipedia.org/wiki/Quark
Hi Aurora, my 8 year old son wants to know what happens if the up quark in a neutron flips to a down quark. So there would be 3 down quarks in the neutron. Thanks.
Hi Lynn,
Q1: Unit 7 is a bit different from the rest of the units in that Lesson 1: Particle Physics is mostly for the upper grades and Lesson 2: Astronomy is for both grades. Particle physics dives a bit deeper into the inner workings of atoms, most of which is appropriate for most kids 7th grade and up. To answer your question specifically, you can find the brief answers to the exercises in the answer key, and expanded answers in the introduction video at the beginning of the section as well as in the K-8 reading download.
PET scans are used int he medical field to image the inside of the body. Doctors can see what’s going in your actual body tissues when they do this type of testing. Scientists haven’t found any long-term ill effects to using this techniques, as the body is constantly replenishing cells, and the amount of matter-antimatter annihilations are so small on the scale of the body.
Q2: Great question! And not an easy one to answer. The electron and nucleus (protons, actually) are bound together by the electromagnetic (EM) force. The electron has mass, and is moving quickly around the core. If the EM force were to suddenly disappear, the electron would fling away from the core (think of swinging a bag of oranges around your head, and suddenly letting go of the bag).
The question of why doesn’t an atom collapse (or why doesn’t the electron fall into the nucleus) is a harder question to answer and requires a deeper look into college-level quantum mechanics. Ernest Rutherford, when he discovered the atomic nucleus in 1911-1912, proposed that electrons don’t fall into the nucleus for the same reason that planets don’t fall into the sun: their velocity is sufficient to exactly balance the attraction exerted, and so they maintain orbits.
To keep a planet in orbit requires that the planet be moving. The velocity is constantly changing direction (to move around the sun, it’s constantly making a turn to stay in orbit), and when velocity changes, it’s called acceleration (covered in Unit 2). However, a peek into college-level electromagnetic equations state that if an electron does this, it will give off light, lose energy, spiral down and be absorbed by the nucleus. But we see that doesn’t happen at all (if it did, things would very quickly dissolve into a puff of light and be gone).
Electrons are what we call ‘quantized’. Here’s what that means: electrons can only be in certain shells. They’re not like planets (which can orbit anywhere), but have discrete, set locations that they can exist at (this is covered more in Unit 7, 8, and 9).
The energy of an electron can only be in specific amounts. Coins can only exist in discrete amounts also – you can’t cut a dime in half to make two nickels. You either have ten cents or no cents. Max Planck and Albert Einstein showed that energy is quantized, having only certain possible values.
There are more parts to this concept, but those should get you started in thinking about your question. When your child hits college, they’ll learn about how finding the exact location and speed of the electron in the nucleus isn’t possible with the physics we have today (it’s a violation of the Uncertainty Relation), and how to approximate the velocity by solving a complicated thing called the ‘wave equation’. They’ll also learn electrons are fuzzy particles, not solid objects like marbles, and you need a type of math called ‘probability’ to deal with them… and even then you’re never sure 100% of your answer.
Thanks for the note about the typo – we’ll get the revised version up soon.
Hi!
A few things from Unit 7:
1. Exercises for Particle Physics:
RE the answers for the exercises: Do you elaborate when you provide the answers to the exercises, or should I be able to find all the information that is in the answer section somewhere in the readings and/or videos?? See examples below:
#2 – Quarks – The reading states that quarks make up the nucleus of the atom. The answer also states that the proton is made up of 2 up quarks and 1 down quark and a neutron is made up of 1 up quark and 2 down quarks. I see in the 9-12th grade highlights, it mentions part of this. Is this discussed anywhere in the lower-level reading or the video??
#8 – Where are PET scans mentioned in the readings or video?
Typo: #10 – The answer states that when an atom spontaneously undergoes fission (splitting), it’s called fission (s/b radiation).
2. Questions on atoms:
If an electromagnetic force keeps the electrons from flying away from the nucleus, what prevents the electrons from attaching to the nucleus? The electron is zooming around the nucleus but what makes it move? Why doesn’t it slow down and attach to the nucleus? Photons pull them together, but what keeps them apart?