Waves Unit Reflection

How does the use and study of waves affect societal well-being?
During this Unit we learned about Seismic Waves, Water Waves, Electromagnetic Waves, and Sound Waves. In the beginning of the unit I didn't really know anything about wave only about Microwaves but not as much as I know now. Also, I know about the waves that are in pools or at the beach. Without waves how would we be able to help humans from death and diseases without UV rays (new born babies in hospitals), x-rays or gamma rays (used in hospitals to treat cancer). Doctors use magnetic resonance and radio waves to see a picture of human’s tissue. Radio waves and the Doppler effect are used to find the speeds of moving vehicles and of moving balls at sport events such as tennis matches. 


What did I like?
I really liked how we started the whole unit. How we listened to songs, while that drawing waves, what we thought waves were. It was very good way to see how we would be embarrassed, because of our small knowledge about waves. 
What would you change or add for next year's grade 7 students? 
I think it would be more fun if there would be more group work

Food Irradiation

Step 1: During class we talked about food irradiation. We were assigned in partners to research about the cons and pros of food irradiation. Monica, Teodora and I were researching about the pros, Roy and Aleksaj were researching about the cons of food irradiation. 


Step 2: Irradiation is the process of treating food and other consumer products with gamma rays, x-rays, or high voltage electrons to kill potential harmful bacteria and parasites, delay sprouting, and increase shelf life. Irradiation is also referred to ass "ionizing radiation" because it produces energy waves strong enough to dislodge electrons from atoms and molecules, thereby converting them to electrically charged particles called ions.  Ionizing radiation reduces the number of disease causing organisms in foods by disrupting their molecular structure and killing them.  Other terms commonly used to identify ionizing irradiation are "cold pasteurization" and "irradiation pasteurization".
Food irradiation makes food safer to eat, and also could stay fresh for longer, but it can kill many healthy vitamins, like vitamins A, B-1, E and C, that are useful in the daily life, but also cooking the food can kill those vitamins. As well the once that are harmful to human. 


Step 3: 

Pros: 

• Irradiation can kill or substantially reduce the number of potentially dangerous organisms in foods.  Estimates range for 90 to 99.9%.
• Irradiation can kill insects and pests infesting foods such as grains and flours without leaving chemical residues.
• Irradiation can be used to sterilize food for immune-compromised individuals such as AIDS 

Cons:

• Irradiation at recommended doses will not eradicate all pathogens. The remaining organisms are by definition "radiation resistant" and may create super strains of hard-to-kill pathogens.
• Irradiation at current allowable levels is ineffective against viruses such as the Norwalk virus found in seafood.
• Irradiation can only be used on a limited number of foods.  Fresh produce such as lettuce, grapes, tomatoes, and cucumbers turn mushy and unpalatable.  Thus, the risk from contaminated fresh produce, a major carrier of food borne disease, cannot be fully addressed by irradiation.

Step 4: You see two containers of a food at the supermarket.  One is irradiated; one is not.  The price is the same.  Which would you buy?  Explain why. 

I think if I always had the choice to pick between natural and not natural food, I would always pick natural. I would chose that food because its the same price but natural food is healthier since it has the vitamins, but irradiated food kills most of those vitamins that would be healthy for human.

Noise Pollution

What is Noise Pollution?  Noise pollution is a type of energy pollution in which distracting, irritating, or damaging sounds are freely audible. As with other forms of energy pollution (such as heat and lightpollution), noise pollution contaminants are not physical particles, but rather waves that interfere with naturally-occurring waves of a similar type in the same environment. Thus, the definition of noise pollution is open to debate, and there is no clear border as to which sounds may constitute noise pollution. In the most narrow sense, sounds are considered noise pollution if they adversely affect wildlife, human activity, or are capable of damaging physical structures on a regular, repeating basis. In the broadest sense of the term, a sound may be considered noise pollution if it disturbs any natural process or causes human harm, even if the sound does not occur on a regular basis.


How does it effect to your ear? Your ears were designed to process naturally-occurring sounds, and they are beautifully adapted to handle that task. They are able to detect sounds of intensities that vary across many orders of magnitude, and to meaningfully transmit those signals to our brains. But they are not well equipped to deal with the high noise levels that are common today, because such loud sounds occur only rarely in nature. The ear is a complex structure, processing sound through several stages in the outer, middle, and inner ear. Although the eardrum may sometimes be ruptured by severe noise (acoustic trauma) or pressure changes, the part that is most vulnerable to damage by noise lies more deeply, in the inner ear, where the final processing takes place before the sound is converted into nerve impulses that are transmitted to the brain. The prominent structure in the inner ear is the spiral-shaped cochlea, which is a fluid-filled tube lined with delicate, microscopic hair cells that pick up the vibrations caused by sound waves. When they are overworked by too much exposure to loud sounds, the hair cells become metabolically exhausted and can temporarily lose their function. Fortunately, they are able to recover from the auditory fatigue caused by too much noise, but if overexposure is too long or too frequent, they can't cope, and they die. There is no pain or bleeding when this occurs. 


Ways you can protect yourself from noise pollution:

• Know which noises can cause damage (those at or above 85 decibels)
• Turn your music down, especially when using headphones
• Wear earplugs or proper earmuffs when involved in a loud activity (special earplugs and earmuffs are available at hardware and sporting goods stores)
• Be alert to loud noise in your environment
• Protect the ears of children who are too young to protect their own
• Make your family and friends aware of the dangers of noise pollution
• If you think you have hearing loss, see your doctor or nurse. You should have a medical exam by an otolaryngologist  (a doctor who works on the ears, nose, throat, head, and neck) and a hearing test by an audiologist (someone who tests and helps people with hearing loss)  

How can science reduce noise pollution?

Trees, not only absorb carbon dioxide, provide shade, prevent erosion, but they can also help muffle noise. Think of trees as big, leafy, air-purifying, oxygen-producing, white noise machines. Acting as shields, trees reduce the intensity of the sound waves considerably and it is the sound produced by the wind passing through the leaves that really helps muffle noise. A properly-designed buffer of trees and shrubs can reduce noise by about five to ten decibels-or about 50 percent as perceived by the human ear, according to the USDA National Agroforestry Center. For maximum effect, experts suggest planting a variety of both hedges or shrubs and taller trees to create a wall of foliage from the ground up. Such examples as cottonwoods, poplar and aspen trees are especially good at noise reduction because their leaf-shapes produce a good, strong rustling sound

Tunning Fork Lab

Guiding Question:  How does the density of a material affect the properties of sound traveling from a tuning fork?
Hypothesis:  If the dense of the surface is high then the pitch will be lower. 
Material: 

• Tuning fork
• Two types of surface:
• wood
• glass

Procedure:
1. Take a pencil and a notebook before you get started with your experiment, because you wouldn’t want to miss something out, otherwise everything would be incorrect.
2. Take a tuning fork of normal size and hit it on each material. You should feel the vibration of the tuning fork while you’re holding it.
3. Get a timer/watch stop and time how long the tuning fork vibrates. Save your observations on a document or in your notebook.
4. Repeat the steps above.

Material	Observation
Wood	Long vibration, lasts for long time
glass	Annoying sound, loud and intense

Conclusion: My hypothesis was right if the material has higher dense then it will have a lower pitch.