Unit 9

This picture shows what we learned in class today. Today we learned all about waves today. 

A represents crest or the highest

B represents trough or the bottom 

C represents the amplitude or the distance from the crest or the trough to the equilibrium 

D represents a loop 

E represents a wave 

F represents the nodes which are places between the loops with no movement

The orange parts represent the equilibrium 

Waves are ways of transmitting energy 

Vibration is "wiggle" in time.

Medium is the material that the wave is in. Some waves need a medium to go through. 

Wave length is the length of a wave, it can be measured from two identical portions of the wave. Ex. Crest to crest. 

We also learned about different kinds of waves. There are two types, transverse and longitudinal. Transverse waves are waves that have energy that moves perpendicular to wave velocity. Ex. light Longitudinal waves are waves that have energy that moves parallel to wave velocity. Ex. sound. Period is the time it take for one cycle to occur. Frequency is how many cycles go by in a second, the units for frequency are hertz or 1/ seconds. There are three important equations that we learned: 

Period= 1/ frequency    Frequence = 1/ Period    Wave velocity= frequency x wave length 

We learned a bunch of other terms like the principle of superposition which is when two or more waves are moving through the same space. Depending on direction waves can have a positive sign or a negative sign. If two positive waves or two negative waves collide they have a constructive interference and join together to create a large wave. If one big positive wave collides with a small negative wave they have a destructive interference and will result in a smaller wave. If a positive wave and a negative wave of the same size collide they can result in a flat wave. Nodes are areas of no movement, antinodes are places where there is the most movement. 

Water Bottle Rockets 7/10 !

Our water bottle rocket included:

One two liter soda bottle
4 triangle shaped 5 by 1.5 inch fins-
A big funnel that we used as our cone
A ball of clay inside the funnel
A piece of saran wrap to cover the clay
A circle shaped parachute made out of a garbage bag
Four long strings attaching the parachute to the rocket
A lot of duct tape

We got our design from instinct and the internet. The internet told us to make triangle shaped fins, but we chose the size of them. We chose poster board for our fin material because we knew it was sturdy and light. Matt brought in the funnel so we used it. We used a ball of clay because a website told us that clay was a good mass to use and it would stay well in the cone. We at first used a glass circle to cover the clay so the parachute wouldn't stick to it, but it didn't work well so we got a piece of saran wrap and covered the clay so it wouldn't stick to the clay. We used a garbage bag because we thought it would be sturdy and a good size. We cut it into a circle because a website told us to, and we knew that a wider parachute was best. At first we had short strings attaching the parachute to the rocket but Mr. Blake told us to change to longer strings when our parachute failed to do well. We used duct tape because duct tape is the strongest tape.

What worked as planned was the clay, the shape and size of our bottle, and our fins. All these things worked well, and we didn't have trouble with. What didn't work as well was the parachute, the cone, and the strings. The parachute didn't come out more than half of the time. Our small cone broke on our 5th trial because it fell downward and cracked when it hit the ground, good thing we had a bigger cone as a backup. This bigger cone ended up working out much better. It was bigger so that the parachute could fit and open up when in the air. The short strings didn't work yesterday so we got longer strings. The longer strings always got tangled though and on our 16 second trial they got twisted as the rocket was falling down.

PSI: 80
Amount of water: About a liter
Times:
5.59 s
6.71 s
11.87 s
Avg: 8.06 s
8.1 s
5.1 s
6.79 s
9.4 s
5.4 s
16.7 s
Avg: 8.58 s


Project taught us: 

This project taught me that a light mass is better. Our water bottle rocket was pretty light and so it went up higher, lots of other rockets were heavier so they didn't go up as high. This shows us physics because more mass means more inertia. The heavier rockets wanted to stay down so they didn't go up as high.
Also on the first day we filled our rocket up with 1/3 of water, which was not as successful. On the second day we filled it up with 1/2 of water which resulted in a higher rocket.
For your rocket to go high you also need a high PSI too, more pressure means a higher rocket.
We learned from this project that wider and bigger parachutes were also better. This is because they catch more air and result in a longer falling time.
The cones of our rockets couldn't be too secure on the rocket because as the rocket is going up friction is pushing down super hard on the rocket and for the parachute to work the cone needed to fall off, so you had to be sure your cone was loose.
 Longer strings were better because it allowed the parachute to take on more air. Some groups had paper cones, we had a plastic one and ours was more successful because it was stronger against the wind and didn't crush when it fell.

I'm happy with the time of our rocket. All our low times were because our parachute failed to come out, but when we changed to a higher cone, the parachute came out easily. It was really scary watching the rocket fall because the parachute would always only come out at the end about 15-18 ft above the ground. When the parachute came out though it dropped really slowly resulting in a slow time.

Water Bottle Rockets

Our rocket consisted of one 2 liter bottle, a funnel as a cone, a circle parachute that was hidden under the cone attached by four long strings,  a ball of clay under the cone, a small glass circle over the clay and 4 small fins on the sides of our bottle. The creation of our bottle rocket took a lot of time, thought and failure to come up with.

Our first creation was only a bottle with a small plastic bag as its parachute attached with tape. The next day we added in a big garbage bag as the parachute and attached it with four short strings. We tested this model on a balcony and decided we should change it a little. We read on the internet to cut the parachute into a big circle and attach it with four short strings, so thats what we did then we put a cone over the parachute. We also read that it was a good idea to add fins so we  hot glued and duct taped in triangle shaped 5 by 1.5 inch styrofoam project board fins. We knew we had to add a mass to the cone, and one site said to add clay. We grabbed a ball of clay from the clayroom and stuffed it in the tip of the cone. Then we went down to the field to launch.

For our first and second trial we used the same amount of water, about 1/3 of the bottle. On our first trial our rocket stayed up for 5.59 seconds, but the parachute didn't work so we tried again, we added in a small glass circle to cover the clay in our cone. We did this because we thought the parachute was sticking to the clay so we put that in so it hopefully wouldn't stick.  On our second trial our rocket stayed up for 6.71 seconds, but still our parachute was not working.

 Mr. Blake suggested we make the strings of our parachute longer, so we traveled up to the classroom and changed the length of the strings. We came back down for our final trial and filled the bottle up 1/2 with water. We pumped up the rocket a lot, build a lot of pressure and on this final trial our rocket stayed in the air for 11. 87 seconds. Yay the longest yet and past 10 seconds! The rocket went up high and our parachute kicked in about 15 ft from the ground. We were happy with 11.87 seconds so we didn't change anything and we hope that tomorrow our rocket will do 11. 87 seconds again.

Unit 8- Work & Energy & Power

Today we learned about powaaahhhhhh, but before that we learned how to graph energy. Energy graphs are different from distance vs. time graphs, velocity vs. time graph or acceleration vs. time. They aren't line graphs, they are bar graphs. On these graphs you have spots for gravitational potential energy, spring potential energy, kinetic energy, work and total energy. You have to read the word problems, and figure out which energies are present then graph them out.

We also reviewed work. Work is a change in energy. Work= force x distance and force= mass x gravity.The unit for work is joules. Energy is always conserved so you can convert work into other things like potential spring energy, gravitational potential energy, and kinetic energy. This is proven by the law of conservation of energy. For these problems use the equation Ein=Eout 

This photo represents a lab that we did in class today that involved power. We had to choose a person, get their mass, figure out the distance of the stairs and then time the person running up the stairs. From this information we could figure out their force, their work, and their power. 

Power is the rate at which work is done. Power= change in energy/ change in time= work/ time. The unit for power is watts or (joules/seconds). Through a lab we learned that a larger mass has a larger power.

Unit 8

Today in class we learned all about energy. I posted a picture of powerade because it is energy drink and represents energy. There is a picture of a person running to represent kinetic energy, energy of motion. There are pictures of a spring and a rubberband because those are sometimes involved in problems involving energy like spring potential energy problems. Law of conservation of energy- energy cannot be created or destroyed it only changes form. Energy is a scalar, meaning it only has magnitude not direction .

We learned about 3 different types of energy:

Kinetic= energy of motion (KE= 1/2 x mass x (velocity)2 = 1/2m(v)2

Potential (gravitational) energy (PEg= mass x gravity x change in height = mgh 

Spring potential energy (PEs= 1/2 x spring constant x (distance the sprig is stretched or compressed)2 = PEs= 1/2k(d)2

Hooke's Law (Fspring= - kd)

Work= change in energy 

W- force x distance (N•M or Joule) 

We also learned some graphing rules 

 1) The area under a curve of a force vs. distance graph is work done 

 2) The slope of a force vs. distance graph is spring constant. 

We completed a bunch of problems all about energy and for all of them we had to use the equations above ^^^ we also used the equations: work=change in PEg and work= change in KE. This problems are pretty simple, once you figure out which type of energy is present in the problem. 

Egg Drop Lab

I thought our capsule would work because of a lot of things. First because our box was PACKED with bubble wrap and our egg was wrapped in bubble wrap and a small towel. Since our egg was surrounded by bubble wrap, there was no empty space for the egg to move around and crack. We put our egg directly in the middle of the box and this ensured that no matter where our capsule landed, no matter if it turned over or turned on it side, the egg would have the same amount of bubble wrap secured around it as any other side. Our capsule was also securely wrapped in duct tape that we knew would be very strong and keep the box from opening up. Our cardboard box provided a great, stable and not too small, not too big surface area. This surface area created a good amount of air resistance that pushed up on our capsule. Our capsule was also very light and because of that the gravitational force pulling down on it wasn't so strong. Another force that was exerted on the capsule was friction. All through the fall friction was pulling up on our capsule

Our capsule was SUCCESSFUL! It was successful because our capsule when falling turned a little bit around, it ended up landing on its corner which Mr. Blake said was the best place for it to land because that means the force of the ground is hitting the corner and not the whole 18.5 cm bottom of the box. Our capsule was very stable, we didn't take too many risks and we pretty much knew that our capsule would succeed because it was simple. The bubble wrap was a good idea. The bubble wrap definitely cushioned the blow, increased the contact time with the ground, and kept the egg stationary.

Unit 7

Today we did a couple of activities. The picture above shows one of the examples we completed. Two people threw a ball back and forth on a "danger" board and a hover board. Depending on the persons mass they could stay stationary or move back a bit.

Today we also reviewed what we learned yesterday, which was all about momentum (p)
Equation to find momentum : p= m (mass )v (velocity) and momentum is a vector quality.
Impulse is change in momentum and to find the change in momentum you can use this equation : change in momentum=(force)(change in time). We reviewed the law that can be called the law of conservation of momentum which states that in a closed system momentum of a system is always conserved. The unit for momentum is kg•m/s. Another thing that we learned today is that the area under the curve of a force vs. time graph is impulse. The problems that we went over all involved the equation : change in momentum = avg force • change in time. The change in momentum for this equation is momentum final - momentum initial. Also problems like these require you to write a axis, because just like the cart lab that we did in class going one way needs to be positive and going the other way needs to be negative.

Other things we learned today are that forces between two colliding objects of different masses on each other are the same, impulses between two colliding objects of different masses are also the same. Changes in momentum are the same because changes in momentum equal impulse. Changes in speed are different though.