The Top Ten Blog: Physics is in the house!

In this blog, I'm going to attempt to make a top ten list of the physics concepts seen in the household. The list is in no particular order.

1. Motors- Found in fans used to cool the house. Uses the concept that a current carrying wire inside of a magnetic field produces a force. The coil of wire inside, let's say the fan, is supplied with a current from the outlet on the wall, then there is a magnet inside that creates a magnetic field. This causes a force on the wire, producing a spin, thus causing the fan to rotate and cool your home.

2. Electric Potential Difference- IN ORDER for current to flow from the wall outlet to your appliances there must be an electric potential difference. With no electric potential difference your appliances will not be powered.

3. Lightning Rods- Pointy pieces of metal located on roofs that leads to the ground in order to ground the charge from the lightning. Now, I understand these are not found on every house, but they are very important and in the future I think they will become mandatory on every house. They work because scientists discovered that positive charges group up in the points of objects. The negatively charged clouds send a charge down (lightning) that is the grounded. Making it completely harmless and protecting your home.

4. Parallel Circuits-An electrical circuit in which electrical devices are connected in such a way that the same voltage acts across each one, and any single one completes the circuit independently of the other (Paul G. Hewitt). This is how your appliances are wired; so that when one malfunctions the others will remain on. 
5. Transformers- Use alternating current to crate a change in the magnetic field so charges can be transferred across the primary and secondary coils, either increasing or decreasing the voltage. They are used in computers and phone chargers to make sure they do not receive too much voltage.

6. Alternating Current- Found in every thing other than batteries. The electrically charged particles repeatedly reverse directions, vibrating about fixed positions. In the U.S the vibrational rate is 60 Hz.

7. Direct Current-The electrically charged particles flow in one direction. Used on those duracells and energizers we use, in which the current flow from a negative to positive end. Batteries are basically the only things you will find with this type if current.

8.  Fuses- Used to make sure your appliances are not flooded with too much current. Fuses are wired to the parallel circuits in your home by a series circuit, so when the fuse blows because it received too much current, it will shut down the whole system. In a series circuit each appliance is dependent on each other to complete the circuit. A fuse can be seen as a home's security system against too much current.

9. Charges inside a dryer- This is just a fun one, not that useful. But, have you ever wondered why your clothes stick together after being in the dryer? It’s because as they rub together they steal electrons from each other and become charged. Leaving some positively charged and others negatively charged, since like charges attract they stick together.

10. Outlets (American vs. European)- American outlets provide 120 volts and European outlets supply 220 volts. We cannot use our appliances in European outlets because they will supply our appliances with way too much current, causing them to malfunction. But they can use ours; their appliances will just be less efficient.

All of these physics concepts explain why stuff in your household happens the way it does, such as your clothes sticking together, or they contribute in keeping your home comfy and on smooth running machine (maybe that's not a proper term since we aren't talking about doing any work).

             

Unit 8 Reflection

Unit 8 was by far the most attractive unit yet. It was all about magnets, magnetic fields, and how we can use them in relation to electric fields. Paul G. Hewitt defines magnetic force in this way:

1. Between magnets, it is the attraction of unlike magnetic poles for each other and the repulsion between like magnetic poles.
2. Between a magnetic field (the region of magnetic influence around a magnetic pole or moving charged particle) and a moving charged particle, it is a deflecting force due to the motion of the particle: The deflecting force is perpendicular to the velocity of the particle and perpendicular to the magnetic field lines. This force is greatest when the charged particle moves perpendicular to the field lines and is smallest (zero) when it moves parallel to the field lines. 

Thanks Mr. Hewitt!

After we learn that stuff we can begin to apply these concepts to real life. So, when a paper clip becomes magnetized by a magnet what is exactly happening? First off it is useful to know that magnetic fields always travel from north to south inside of a magnet.
 


 
The paperclip has charged particles inside of it and once it comes close to the magnet the domain of the paperclip aligns with the poles allowing it to become magnetized. The paperclip will become magnetized whether it comes into contact with the north or south pole because the domain will just shift.
There are things called electromagnets which is just a magnet that is produced by electric current. Usually in the form of a wire coil with a piece of iron inside the coil. This also goes along with the fact that current carrying wires inside a magnet field feel a force. Electromagnetic induction is the induction of a voltage when a magnetic field changes with time.
We used these concepts in the motors we built, which you can read in my previous motor blog @dorianakamrphysics.blogger.com
Transformers and Generators come next. As I learned from my fellow physicist Paul Jordan, a generator is basically a reverse motor. It uses mechanical energy to create electrical energy by turning a coil of wire within a magnetic field. A transformer either lessons or increases the voltage to an appliance using coils of wire. But I think Wes and Jared explained this better.

 Equations from video: Primary Voltage/# of coils = Secondary Voltage/ # of coils (for transformers) ; Power in = Power out

 

The things that I found difficult in this section was explaining the magnetic field around the earth and why the cosmic rays are stronger at the poles. Just now have I grasped then fact that it is because the magnetic force is stronger there and they can not enter on the sides, because the magnetic field runs parallel to the earth. The problem solving skills came in we had to find how many coils were in the primary and secondary coils of a transformer. It helped me learn how to better cross multiply. This unit applies to real life because things such as computers use transformers, and credit card scanners use electromagnetic induction.

 

Physics Photo Project

         How A Light Bulb Works

 The picture I chose to take is simple, but shows one of the most useful everyday physics concepts. My picture is of a light bulb being lit. So how does a light bulb work? First off, the light bulb is connected to the wall, which supplies it with a voltage, creating an electric potential difference, therefore allowing a current to flow. The energy from the wall socket travels into the light bulb heating up the tungsten filament. It is very similar to molten steel, which glows white hot when heated up. However, if the energy from the wall socket heated up the tungsten filament in open air with the presence of oxygen it would simply burn away. Which is why the filament is encased in glass that has had the oxygen sucked out of it. But what exactly causes the filament to heat up and produce light? It is a principle known as resistance, or an objects unwillingness to let the current flow through it. The filament tries to retain the electrons as they pass through, so they must be forced to travel inside of the filament. This force provides heat, which is released and creates the light we see. On top of the light bulb you can see that it is labeled sixty watt and one-hundred twenty volt. The sixty watts is the power, which equals current x voltage (voltage needed is one-hundred twenty). Furthermore, current equals voltage divided by resistance. These are the equations needed to figure out just how much current and resistance the light bulb has. In this case the current is 0.5 amps and the resistance is 240 ohms because the voltage is 120 and the current is 0.5 If we manipulate the equation current equals voltage over resistance, or ohms law we get the answer for resistance. That right there is the basics of a basic light bulb.