October 19, 2007
Hey guys!! Have you (by any chance) been able to find any websites about the composite materials used in taekwondo gear??
October 15, 2007
Today, I (Tina) came to a final conclusion of my experiment. The past few days, I have been recording the results of salt on the density of tap water. My Results:
The Effect of Salt on the Density of Water
Amount of Salt (g)
Trial 1
Trial 2
0 g
1 g/cm3
0.996 g/cm3
1 g
1.01 g/cm3
1 g/cm3
1.5 g
1.04 g/cm3
1.070 g/cm3
2 g
0.99 g/cm3
1.048 g/cm3
2.5 g
1.05 g/cm3
1.073 g/cm3
3 g
1.03 g/cm3
1.077 g/cm3

In general, the densities increased as the salt increased. Although, some data dropped well below the previous and following measurements. For the most part, salt water is denser (more dense) than pure tap water.
I Wonder...
I wonder what the results would be if we used spring water instead of tap water?? Distilled water??

Our Opinions on the Compacted Curriculum for Chapter 2

A. Research building materials or sports equipment and report on how the properties of the materials make them useful or cause problems.

  • It would be fun to find out about the properties of different materials. I have heard that sports are the "cutting edge" of technology. You would think that medicine would be higher than sports, but I suspect they are at the same spot in rank. -Tina

Brandon and I decided to do a mix of A and B. We could have some of the displays be about sports equipment or building materials and why they are made the way they are.
We are going to bring in a baseball baseball glove, bat, and a cut in half baseball. We were also going to bring a soccerball, football, field hockey stick, golf club, basketball, and tennis racket! Please tell us if you have any more ideas or if you just have something to say!! =]

I found another sport. Fencing, and we could ask Adam Dymit if he could bring in a fencing sword or something.BK

Hey guys!! It's Tina. I love your idea. I was also thinking: I do tae kwon do, and I could bring in some of my gear that we use for sparring (like fighting). I have some old gear that we could cut apart. By the way: COOL baseball :P

We're glad you thought of tae kwon do!! If you bring in your tae kwon do gear, we will bring in the rest of the things for the museum walk-through.
Monica and Brandon

Now that we know what we are doing for the project, we should probably decide who does what. I was also thinking (if you guys want to) that we could make a podcast of the museum walk-through.
Tina :P
Hey guys!! I found this table about head injuries:

Estimated Head Injuries for Selected Sports

The following table presents estimates of the number of head injuries treated in hospital emergency rooms in the U.S. for 2004 for selected sports.

Sport Category
Estimated Number of Head Injuries2, 2004
Estimated Number of Hospitalized Head Injuries3, 2004
In-line skating1
Scooters, unpowered
Horseback riding1
Ice hockey1
Source: National Electronic Injury Surveillance System, Directorate for Epidemiology, U.S. Consumer Product Safety Commission, 2006.
*sample size too small to report estimate
1 activity, apparel, or equipment
2 includes injuries to head, ears, mouth, eyes, and face
3 includes cases where patient was admitted, was held for observation, was treated and transferred to another hospital, was dead on arrival or died in the ER.

B. Create a Matter Museum – Collect objects and display them with information about the materials in the objects. Your museum should have examples of as many different physical properties as possible

  • I, personally, LOVE this idea. I kind of reminds me of last year's Gross-Out Day! We got to learn about different things by means of a walk-through museum. -Tina

C. Create a podcast that teaches 8th graders about the physical and chemical properties using objects from home to demonstrate.

  • I really like to talk, and I really love making Podcasts. This is a fabulongoshoomarvelishleywonderpipical idea for anyone who likes to talk and likes people listening to them. -Tina

external image insideball.gif

The outside covering of a basketball is made of synthetic rubber, rubber, composition, or leather. The inside consists of a bladder (the balloon-like structure that holds air) and the carcass. The bladder is made of butyl rubber, and the carcass consists of treads of nylon or polyester. Preprinted decals are used to label the ball, or foil is used to imprint label information. Zinc and copper plates are used in a press to either affix the decals or imprint the foil.

In the early stages of the game of football, a pig's bladder was inflated and used as the ball. By comparison, today's football is an inflated rubber bladder enclosed in a pebble-grained leather cover or cowhide. This material is used because it is both durable and easily tanned.

A golf ball is made up of mostly plastic and rubber materials. A two-piece ball consists of a solid rubber core with a durable thermoplastic (ionomer resin) cover. The rubber starts out as a hard block, which must be heated and pressed to form a sphere.
The three-piece ball consists of a smaller solid rubber or liquid-filled center with rubber thread wound around it under tension, and an ionomer or balata rubber cover.
During the 1970s the interior of the ball improved further, thanks to a material called polybutadiene, a petroleum-based polymer. Though this material produced more bounce it was also too soft. Research at Spalding determined that zinc strengthened the material. This reinforced polybutadiene soon became widely used by the rest of the manufacturers.

Most volleyballs have three levels of construction. The first level is a rubber bladder made from the same material as a bicycle inner tube. The bladder is then attached to a cloth layer made of material similar to cheese cloth and sealed with a rubber type glue. The outer layer is made of leather and is glued to the cloth layer.

The ball is hard and of plastic (sometimes over a cork core) and is often covered with indentations to reduce hydroplaning that can cause an inconsistent ball speed on wet surfaces.

The majority of wood baseball bats today are made from northern white ash harvested from Pennsylvania or New York. White ash is used because of it's hardness, durability, strength, weight and "feel".
Aluminum bats are lighter, stronger and can hit a baseball significantly further than wooden bats.
18781521_bf187bb448.jpg 464878356_9ad79dbd6d.jpg

The international rules specify that the game is played with a light 2.7 gram, 40 mm diameter ball. The ball is required to have a coefficient of restitution of 0.94. The 40 mm ball was introduced at the 2003 World Table Tennis Championship. However, this created some controversy as the Chinese National Team argued that this was merely to give non-Chinese players a better chance of winning. A 40 mm table tennis ball is slower and less "spinny" than a 38 mm one. The ball is made of a high-bouncing gas-filled celluloid ball. A star on the ball indicates the quality of the ball. 3 stars is the highest indicating that it is of the highest quality.

Aluminum rackets are usually made of one of several alloys. One popular alloy contains 2% silicon, as well as traces of magnesium, copper, and chromium. Another widely used alloy contains 10% zinc, with magnesium, copper, and chromium. The zinc alloy is harder, though more brittle, and the silicon alloy is easier to work. Composite rackets may contain many different materials. They usually consist of a sandwich of different layers around a hollow core or a polyurethane foam core. The typical layers of a composite racket are fiberglass, graphite, and boron or kevlar. ceramic fibersare used for added strength.
Other materials found in tennis rackets are nylon, gut, or synthetic gut for the strings, and leather or synthetic material for the handle grip. Nylon is probably the most common string material, and only a few professionals still use gut, which is made from twisted cow or sheep intestine. Synthetic gut is made from nylon which has been twisted to achieve the same effect as natural gut.

Abstract. The chemical constitution and physical state of natural rubber in its viscous, high-elastic and crystalline conditions are described. It is shown that those depend on long hydro-carbon chains which are normally coiled and tangled. The high elasticity of rubber is made possible by the ability of the chains to straighten and recoil. On breaking down the cohesion between the chains by various means, rubber has some of the characteristics of a thick oil; whilst, on the other hand, certain conditions, especially those of intense cooling, cause rubber to behave in many respects like a crystalline material. This concept is then extended to a consideration of other rubber-like materials including gutta percha, some synthetic elastomers and finally the silicone rubbers

http://www.tms.org/pubs/journals/JOM/9702/Froes-9702.html -Sports Equipment Page
http://www.pageflakes.com/claguna -A web page that is very effective for sharing info
http://www.nyssf.org/safetyequipment.html -This page talks about helmets, mouthguards, and other equipment.
http://www.cpsc.gov/cpscpub/prerel/prhtml06/06122.html -This is a good site to find an articla about the importance of helmets.
http://www.spacedaily.com/news/materials-00b.html -This is an article about a new-ish composite material that was recently introduced.
Questions?? Comments?? Opinions?? If you have any, please feel free to share them!2