Estrada,+B.

Problem Statement: How strong are different plastic wraps? Hypothesis: When I put different weights on the different plastic wraps, tension will increase, the brandname plastic wrap will hold more weight. If brand names cost more they are probably made better than generic store name brands. Independent Variable: Experiment1: type of plastic wrap, Experiment 2: weights used, Experiment 3: How far the wrap is stretched out Dependent Variable: Experiment 1: Effect of the weight on the plastic wrap, Experiment 2: Effect on the durability of the plastic wrap, Experiment 3: Effect on the durability Control Variable: 1. Same type of plastic wrap each trial (not experiment) 2. Same weight for 1 trial 3. Plastic wrap is stretched out for the same length per trial 4. 5. ___

Benjamin Estrada 4th period 11-11-11 Research Page How strong are plastic wraps?

Elasticity Elasticity is the property of an object or material that causes it to return to its original shape after distortion, For example, when a rubber band is stretched it's shape changes, when you stop stretching it, it returns to it's original form. One of the properties of Elasticity is Hooke's Law, it states that it takes about twice as much force to stretch a spring twice as far. Tension Tension is the magnitude of the pulling force exerted by as string, cable, chain or similar object on another object. If you a climb on a rope, the rope is put under tension. Tension can be measured in newtons and pounds. Forces Forces are one of the basic features in physics. Forces keep matter together. One force is Gravitation. It is a quantitative theory based on observation by Isaac Newton in 1687. He wrote that the gravity force that acts on the sun and the planets depends on the quantity of matter that they contain. Another force is Electromagnetism. James Clark Maxwell combined the ideas of electricty and magnestim and came up with the theory of electromagnetism in 1865. Electromagnectic fields travel at infinite velocity. Nuclear Forces. Since gravitation and elctromagnetism were the only basic forces in the beginning of the 20th century, and electromagnetism is responsible for the forces in the atom, people believed that it was also the cause for the forces keeping the nucleus together. In the 1920's it was known that the nucleaus contained protons. It was thought that electrons were involved in keeping protons together. Problems arose with this theory, " what is the difference between the electrons in the nucleaus and the ones in orbit around the nucleus? ". The only support for this theory was that radioactive decayed electrons were seen to com from the nucleus. But, in 1932 James Chadwick discovered a new type of radiation that could come from the nucleus, his experiment showed that there are electricallly neautral particles inside the nuclei, which were later named " neutrons ".