Tension Test Science Lab

Tension Test:

•   Guiding Question: How does tension affect the amplitude of the spring or slinky?

• Manipulating Variable: Medium – solid slinky

• Responding Variable: Wave => Properties

• Materials:

1.)    Masking Tape (1 roll)

2.)    Meter Stick (1)

3.)    Slinky (1)

4.)    Pencil (1)

5.)    Notebook (1)

•   Procedure:

1.)    Measure the slinky at its average length and record – 4.8 meters.

2.)    Measure the slinky stretched out and record – 10.5 meters.

3.)    Stick tape on the ground in 20 cm lines and 30 cm lines.

4.)    Wiggle the slinky at its regular length with two people holding it on either end.

5.)    Observe whether it has reached either the 20 cm mark or the 30 cm mark.

6.)    Wiggle the slinky at its tight tension stage and observe whether or not it has touched the 20 or 30 cm mark.

7.)    Record all data.

•   Hypothesis: I think that the closer the two ends of the slinky are to each other, the bigger/more amplitude the wave is going to have.  This is because when you stretch a slinky, it’s very taut, and there isn’t any extra slinky room for bigger waves.  When the slinky has less tension, there is more slinky space, and there can be bigger waves.

• Observations: When the slinky is stretched taut, and gently moved from side to side, the middle moves and touches both of the 30 cm tapes.  When you flick your hand once (therefore flicking the slinky), one wave travels along the whole medium, but only touches one of the 30 cm lines.  When we swing the slinky in its short form, it swings to a little behind the 30 cm lines, and much more slowly.  When you flick it with your wrist, it almost touches the 30 cm line, but is slower than when it had been taut.

•   Data Table:

Length:	Tape When Swung:	Tape When Flicked:
10.5 m	Over 30 cm tape	Touches One 30 cm line
4.8 m	Under 30 cm tape	Doesn’t Touch 30 cm Line

• Conclusion: I believe that the answer to our question, “How does tension affect the amplitude of the sling or slinky?” is that the higher the level of tension the slinky has, the greater the amplitude.  My hypothesis was incorrect, but now I think I understand why – when you don’t have a very taut spring to swing, all that extra slinky that is sitting there (kind of like extra fat on a person), makes the slinky swing more slowly and with less momentum.   Without the momentum it needs, the slinky cannot touch the 30 cm lines.  When the slinky has less tension, all that extra material is gone (no more fat on the person).  It can swing more quickly and efficiently, and so it can reach the 30 cm line.  That was a new discovery for me, but now that I’ve conducted our experiment, I now understand what happened.

•   Further Inquiry: In order to improve our experiment, next time we could have two people swing the slinky at either end, and then the third person would catch it at its widest point so as to measure how far it was from the starting line exactly.  That would be more accurate, and it might lead to further inquiries. 

I wonder what would happen if we flicked the slinky up and down instead of side to side – that would probably give us the same results as the first experiment, but you  never know…

Bubbl Us

Here is my Bubbl brainstorming picture:

Green Plastics Reflection

1.) How are these plastics being developed?
          Green plastics are developed with natural sugar - cane, beet, and corn.  Factories turn the sugar into polylactic acid, which they can then convert to plastic.  Regular plastics are made of small molecules called monomers, which, when connected together through polymerization, turn into one big polymer which is similar to one long chain..  The type of polymerization used to make plastic is called a condensation reaction, which means that a small molecule such as water, is released every time two monomers are connected.


2.) What makes these plastics "green"?
          These plastics are "green", because they are made out of beet, corn, and cane sugar  - renewable resources.  This makes bio plastics more eco-friendly.  Lactic acid is an example of a bio plastic.  The thing about lactic acid is that it is only a building block for plastic, because it can't be converted into plastic directly.  This because the chemical reaction that takes place when lactic acid is made produces water.  This water prevents the lactic acid from becoming one long chain like the monomers in regular plastic.  Instead, the lactic acid molecules create a whole bunch of smaller chains.  These are combined in a chemical reaction to make lactide, which then makes monomers that can then be created into polylactic acid. 


3.) What are some of the issues with plastics that were mentioned?
         There are a couple different issues with bio plastic that are bad for the environment.  One is the fact that growing all those crops to produce the sugar to produce the acid, to produce the plastic takes extra space.  We already use a lot of land to grow produce and livestock.  When we do this, we clear away land, cut down trees, and ruin animal habitats.  Sugar crops take up a lot of space which leads to less forests.  Also, there is a limited amount of space where we can grow food.  If we grow too many food crops that aren't for food purposes, we might face a food crisis. 
          Another "con" about bio plastic is that it takes the exact same amount of resources to create it as regular plastic.  If you add up all the pesticides and herbicides that pollute water, as well as the oil used in farming and shipping the crops, plus the energy we need to create the lactic acid and turn it into plastic, we get a pretty big sum of resources. 
         One last example of why bio plastic isn't great is because we can't recycle it with other plastics.  Since bio plastic breaks down into a completely different substance then our average pet bottle, they can't be mashed down and recycled - we would need a completely new recycling system.   Scientists are afraid that if we use too much bio plastic and don't recycle it, it will end up in a land fill.  It is predicted that if we leave bio plastic to biodegrade by itself, it will produce methane gas, which is another greenhouse gas, but worse than carbon dioxide.  Too many greenhouse gasses will lead to a major climate change.


4.) How might these green plastics change packaging practices?
          These green plastics might change the packaging practices by making them less recyclable.  If we make pet bottles out of bio plastic, we wouldn't be able to recycle them, and they will probably produce more carbon dioxide and methane while biodegrading, than they would if we had used regular plastic in the first place.  We would have to devise a whole new recycling system, plus a new symbol for "green" plastics, and use up more crude oil to make extra garbage cans for the new plastic.  Bio plastic might even use up more resources than if we stuck to regular plastic.  Only time will tell for sure, but one thing is certain - bio plastic is a sign that we are trying to take a step in the right direction!

Ultimate Survival Unit Reflection

1.) Reflect on what has helped you in understanding the "big idea" of the unit.
         I thought that the movies in particular helped me to understand the "big idea" of this unit, because they gave many good examples, and good visual aids that really helped me understand what humans are doing. Human Footprint actually counted and gathered everything that we use as humans, and showed each item amount in a variety of different ways. That helped, as well as Food Inc - it actually showed what was going on inside of the factories that produce our meat, and had many interviews with company victims, farmers, and people that were prey of mass food production. Food Inc. and Human Footprint really helped me to understand what humans are doing, how we can help, and how we can maintain the balance between man and the natural environment.

2.) Reflect on the unit question (What is a necessity and how does an organism ensure survival of its species within its environment?) and how it relates to the unit title: Ultimate Survival.
        There are many different ways that organisms ensure the survival of their species. Almost all animals have adaptations that help them to lengthen their lives.  For example, mosquitoes have developed parasitism, a blood sucking proboscis, and light bodies, which help them eat and feed their young.  Tigers in Africa have adapted to the African savanna by growing stripes, which help them to blend in with the tall grasses they hunt prey in.  Some animals will produce two offspring and terminate the weaker one in order to make sure that the strong one will get enough food and pass on it's strong genes to future generations.  Animal adaptations relate to the unit title, "Ultimate Survival," because adapting is ultimate survival.  It's particularly extreme to kill your own child to make sure that the good one lives. 

3.) What would you have liked to do more of?  Less of? 
          I thought that maybe we didn't have to make the owl pellet report such a big deal, or if we did, it would be better to do it all at one time.  We started the lab, but then there was a huge gap of time where we just forgot about it and did other activities.  Then, when we started up with the pellets again, it was all out of our heads, and it was difficult to get back into a rhythm.  It would have been nice to observe something outside, like an insect or some other small creature (not a plant) and take notes on their behavior and see how they ensure the survival of their species.


4.) In your point of view, how well did we investigate the unit question, concept, and area of interaction?  Include this in your reflection as well and give specific examples to support your opinions. 
          I think that there really wasn't anything else we could do to investigate this topic.  We explored the different biomes and ecosystems of the world and the different animal adaptations there, we studied how humans are affecting the planet, we made visuals about different things humans are doing, and the resources we are using up.  We watched a couple of videos about surviving, someone came in and gave a talk, and much, much more.  There's almost nothing left to study about survival. 

Packaging Letter

For our packaging project, I chose cat food, and I later had to write a letter to the cat food company about how they could improve their product. For some reason, I couldn't send it to them by email, but I do have my letter:

Dear Sir or Ma’am from Purina Cat Food Company,
For our science project this quarter, we (everyone in the class) had to pick a normal household item to take apart and examine the packaging. Since we own a cat, I chose to take apart our Purina cat food bag. When I took it apart, I noticed that there were three layers, possibly four. The first layer was the thin plastic touching the cat food, the second was the brown paper, and the third was either colored wax paper or colored paper with a second thin layer of plastic on top.

We also had to list improvements about the packaging we picked. I thought that maybe, instead of having one entire layer devoted to plastic on the inside of the bag, you guys could shrink wrap it so that you wouldn’t waste all that plastic at the top of the bag where there isn’t any food. You could also make the bag a little big smaller and save resources that way, because when I opened my cat food bag, I realized that there is some extra space at the top where there isn’t any food at all, and all you would have to do would be to cut that extra off and use it in the construction of a different bag.

I hope that you will consider my suggestions.
Riena Harker

Reflection:

I think that supply and demand is a big factor in making mass production companies. If we want something, then they'll provide it because it brings in money. If we don't want something, we stop buying it, and companies stop supplying it because it's a waste of money to produce something no one wants to own. Companies use extra packaging to make their products look bigger - worth the amount we pay for them,and to make their products look better than they really are. We see those, and we want to buy them because of all the excess packaging that makes them look so attractive.
I think that our responsibilities as consumers are to make the right choices and demand the right things. What I mean by "right" is products that don't use too much packaging, or companies that treat their livestock decently. "Right" is also companies that are eco-friendly, or donate food/clothing/money to needy charities.
When researching about MY company, Purina, I noticed that, although Purina doesn't really do anything significantly good for the planet, it does do a lot of work for animal welfare. Purina has joined/founded a lot of different organizations such as "Pets for People", "One Hope", "Adopt a Pet", "Delta Society", and more. Most of these societies are to help people and their pets or animals that need homes. I, personally, approve of these actions and am glad we buy from Purina - this is probably what they want me to think, but I'm glad anyway.