Monday, April 18, 2011
Wednesday, April 6, 2011
Today we continued our walking experiment by walking to a location and finding the distance. We have to find out how many steps are taken in 10 seconds. We recorded each persons step and added them and multiplied by 6 and divides by 4. Our formula we need to follow was- EE was our walker and she walked an average of 27.5 steps in 10 seconds. We found out that she took 135 steps in one minute. We divided it by 60 and got 2.25 steps per second. We later realized how we messes up our experiment and had to start over. This time, we took the measuring tape and measured 50 feet. She walked the distance of that, which also failed. Mr. Finley explained to us to find the uncertainty of our steps. That is something we will continue tomorrow. Tomorrow we will also review the numbers that we found today and use uncertainty to receive a better answer for the number of steps S.D
Tuesday, April 5, 2011
Our group started the walking lab yesterday. We started by looking at the equation Distance/ Time = Speed. Then after understood that we devised an experiment.The first step in our experiment we measured a distance of 49 feet 6 inches and that would be the distance we walked. Next we got a timer and we timed each person in our group walking the distance distance three times each. Then we used our equation Distance/Time = Speed for each of our times. My times were 10 seconds, 9.4 seconds, and 9.7 seconds. Then I divided 49.5 feet by each of those times and I got 4.95 ft per sec, 5.27 ft per sec, and 5.1 ft per sec. Next I found my average time which was 5.11 ft per sec. We did this for everyone in the group. After we did that Finley had us measure from his room's door to Mr. G's door which was 198.25 ft. Next we predicted how long it would take KK to walk that distance. Her average speed was 6.24 feet per second. So that means we had the distance and the time for our equation. Next we took the distance with uncertintey and divided it by the speed with its uncertintey. The range we got was 31.74 seconds- 31.79 seconds. Next we had KK walk the distance so we could see the actual time. Her two times were 30.92 seconds and 29.86 seconds. Then we need averaged those out with the uncertinty and we got the range of 30.395 seconds- 30.385 seconds. So even though our prediction was close it still wasn't right on. REMEMEBER TEST ON FRIDAY -DB
Sunday, April 3, 2011
Today we had a substitute and he handed out Lunar Lab packets for us to do. We used a lunar simulation to answer the questions in the packet. Most of the questions were about the phases of the moon and how an observer on Earth would see the moon. We had to work in pairs to work on the packet but we didn't have to finish it. The substitute said we would have time to work on it the next day.
Today, we spent the whole class finishing our Lunar Lab that we started the other day.
Once we finished all four pages of the Lab, we checked our answers with each other. Since everyone is progressing at different rates, some people might have finished checking the labs and started other things (I am not really aware of what other people are doing because I just finished checking the lab at the end of class with my group.)
AT 4th blog
Tuesday, March 22, 2011
Today in class, the first thing that we did in class was discuss why we have seasons. We hypothesized that seasons occur because of the Earth tilting different directions and the Earth's position in orbit. Later we learned that the Earth's tilt is always in the same direction and is
constant. The Earth's tilt is always 23.6 degrees if you draw a line from each of the poles.
Next, we discussed direct and indirect sunlight. We already know that the Earth's position around the sun changes making the Earth point either away or towards the sun. The hemisphere tilted towards the sunlight will receive direct sunlight, and the other will receive indirect sunlight. The amount of direct sunlight on the Earth was displayed in
our simulation we did yesterday in the bottom chart with the yellow dot being either spread or focused.
Next, Mr. F had us do an experiment to prove this. Mr. F has a device that measured the amount of solar energy in a room. Then Brady climbed on top of desk and took a solar energy source (a light) and shone it over the device. As Mr. Finley slowly moved the device upwards, the solar energy decreased 0.1. This proves that direct and indirect sunlight is true.
Therefore, seasons occur because of the position the Earth is around the sun. When the Northern hemisphere is receiving indirect sunlight, it is winter while it is summer in the Southern hemisphere. When the Northern hemisphere is receiving direct sunlight, it is summer while it is winter in the Southern hemisphere.
- J. L. (4th blog)
Monday, March 14, 2011
Tomorrow there will be a quiz so today is a review.
SD pushed MM on a cart towards the wall and he only moved a few feet and slowly. The harder she pushes, the further MM goes and the faster he gets there. The greater the force the faster the acceleration. The more mass of the object the slower the acceleration. The less smooth the surface the greater the friction, the slower the acceleration. And finally, unbalanced force accelerates while a balanced force goes at a constant rate. Today we'll test all these hypothesises by using Phet.
We tested it by having a little man push a box across a friction-less surface (ice). The harder he pushed, the faster and further the box went. This proves our hypothesis.
Then, the man pushed the box and the refrigerator both with 900 N on ice. The box was moving traveled across the screen in about 3 seconds while it took the refrigerator 5 seconds. This proves our hypothesis that greater masses slow down the acceleration.
The man pushed the box much faster on a friction-less surface (ice) versus wood and the box accelerated faster. We made sure the box was moving at a constant rate of 500 N. This proves our hypothesis.
We will test by pushing a box across the friction-less ice to see if we push it once, how much it accelerates. If there is a balanced force of 0 mph, the box goes at a constant rate. This was proved by us not pushing/touching the box.
This is a picture of the little man pushing the box on a wodden surface with unbalanced forces of 777 N.
JF (4th blog)