# emma123321

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## Blog Entries posted by emma123321

Here on earth we are so used to seeing heavier objects fall faster than lighter objects; if I were to drop a bowling ball and a piece of paper at the same time, it is pretty obvious that they would fall at different rates. The paper has a small mass compared to it's surface area, and the bowling ball has a larger mass compared to its surface area. It takes longer for the piece of paper to push away the air molecules, than the bowling ball.

So how come on the moon, a feather and a hammer fall at the same speed?

It has a lot to do with air resistance! Air resistance is the action of friction that slows something moving through air.

A vacuum surrounds the moon, and there is no matter in a vacuum. Therefore, on the moon there is no air resistance. So when Commander David Scott dropped the hammer and feather on the moon, the moon's gravity pulled both the hammer and the feather in at the same rate of acceleration. Because there is no air resistance to slow down the fall, the two objects fall at the same rate.

In the video posted below, Commander David Scott drops a hammer and a feather on the moon! Its an amazing video and thanks to physics, I understand how this is possible!

Have you ever been curious as to how a balloon can magically stick to a wall after rubbing it against some sort of material? This happens because of Static Electricity.

Static Electricity is a familiar electric phenomenon in which charged particles are transferred from one body to another. When you rub your hair or a sweater against a balloon, charge transfer occurs, and Static Electricity is produced. In simpler terms, if you rub a balloon against your sweater, the balloon will steal electrons from the sweater, which leaves the sweater positively charged and the balloon negatively charged. The balloon will most likely be attracted back to the sweater because opposite charges attract. The reason that the balloon will stick to the wall is because the negative charges in the balloon will make the electrons in the wall move to the other side of their atoms (like charges repel) and this leaves the surface of the wall positively charged. Because opposite charges attract, the negatively charged ballon will be attracted to the positively charged surface of the wall.

Something interesting that I stumbled upon while doing this research was some different materials that cause a lot of static electricity are rabbit fur, human hair, cat fur, glass, and dry human skin!

http://phet.colorado.edu/en/simulation/balloons <------- This website has a great simulation that shows more of how Static Electricity works, I know when I first learned about static electricity, this simulation helped me to visualize how it works.
This is completely random, but as I was pondering ideas for a blog I discovered that there is a lot of physics involved in toasters!

Most appliances that heat up, such as hair dryers, irons, and toasters, work by changing electrical energy into heat energy. Toasters are plugged into a source of electricity. From that source, the electric current runs down the wire and into the toaster. The inside of each appliance contains loops of different metals. The electricity does not easily flow through the metals. The metals slow down the electrons and hold up the current, which is resistance. Resistance is a measure of the tendency of a material to resist the flow of an electrical current, in physics. The higher the resistance, the hotter the metal will get. This happens because of the friction of the electrons.

The wires begin to heat up and glow because they are so hot. This heat is what toasts the bread.

Overall this is very random, but its cool to see how everyday appliances like toasters relates to physics!
Today, while looking in the mirror, I suddenly became very curious as to how mirrors work. I remember talking about mirrors in physics class, especially when talking about reflection, but there is even more to it!

The first thing I learned is that there are three types of mirrors: plane, convex, and concave. I will talk about plane mirrors. With plane mirrors, the image is always upright, virtual, and the same size.

The Law of Reflection is a huge part of how plane mirrors work. This law states that when light falls upon a plane surfave, it is reflected so that the angle of reflection is equal to the angle of incidence. This only happens when the reflected ray and the normal ray both lie in the plane of incidence.

This law applies to mirrors because when light falls upon a plane surface, or a mirror, it is reflected, and the angle of incidence and the angle of reflection are equal. When the eyes recieve the reflected light waves, it looks as if the waves are diverging from behind the mirror. This specific type of image is called a virtual image. The light waves don't really pass through that point it only looks as if it does.

This image shows how the reflected angle is equal to the angle of incidence.

Hopefully this provides a little introduction to mirrors, there is certainly a ton more information about how mirrors are related to physics!