Sink or float: A Study on Plastic Density

Sink or Float?A Study on Plastic Density

Problem

• Plastics have contributed to our quality of life in so many ways. Plastic production has also had a major

impact on our environment. Many people recycle and are becoming aware of methods to cut down the

drastic waste of plastics. There are seven types of plastics labeled for recycling purposes. It is important to know how plastics are made and the properties of

different types of plastics. In this experiment, I will test the properties of six types of plastics to solve whether or not you can differentiate between the

various types, based on their physical and chemical properties.

Hypothesis

• By testing six known plastics I will be able to determine unknown plastics

using physical and chemical properties.

Materials

• 70% Isopropyl rubbing alcohol

• Light corn syrup• Water • Beakers• Candles and matches• Tweezers• Cup of water• Permanent marker

• Sprite bottle

• Shampoo bottle

• Blister pack for cold medicine

• Garbage bag

• Macaroni & Cheese container

• Styrofoam bowl

Procedure

1. “1” was written all 5 pieces of the first plastic

2. “2” was written on pieces from plastic type two and so on until all pieces were marked

3. Observe the color and clarity of each piece of plastic.

4. Determine if the sample is soft and pliable, or rigid and hard

5. Prepare the solutions

6. Place one of the five sample pieces of type one plastic in the first solution.

7. Continue testing the density of the same ttype of plastic in the other three solutions.

8. Repeat step seven for the other samples.

9. Using tongs, hold the last sample from each group over a lighted candle, and observe and record the color of the flame and the color of the smoke. Discard the plastic in a pail of water to ensure that all flames will be extinguished.

10.Repeat step 9 with the remaining plastic sample from each group.

Data and Results

Solution Isopropyl rubbing alcohol, Light

Corn syrup, and Water Mixture

Density in g/ml

A 25 ml 70% isopropyl alcohol + 10 ml water

0.91

B 24 ml 70%isopropyl alcohol + 8 ml water

0.93

C water 1.00

D 10 ml light corn syrup + 1 ml water

1.16

Data and ResultsPlastic Sample

Color Clarity(Clear or Opaque)

Soft and Pliable

Hard and Rigid

Flame Color

Smoke Color

Sprite Bottle

Green Clear Yes No Orange Black

Shampoo Bottle

White Opaque No Yes Orange & Blue

None

Blister Pack

Clear Clear Yes No Blue & Orange

Grayish

Garbage Bag

White Opaque Yes No Orange White

Mac & Cheese

Container

White Opaque No Yes Yellow & Purple

Blue

Styrofoam Bowl

White Opaque No Yes Yellow & Orange

Very Black

Data and Results

Plastic Solution A(0.91)

Solution B(0.93)

Solution C(1.00)

Solution D(1.16)

Sprite Bottle Sunk Sunk Float Sank a little

Shampoo Bottle

Float Sunk Float Float

Blister Pack Sunk Sunk Float Float

Garbage Bag Float Float Float Float

Mac & Cheese

container

Somewhat Floats

Partially Sinks

Float Float

Styrofoam Bowl

Float Float Float Float

Data Analysis

Solution Test

When inserted into solution A and B, samples of the soda sank. Though

it floated in solution C, the sample was not afloat completely. Pieces of

the shampoo bottle floated in solutions A, C, and D but did not float in

solution B. The blister pack sank in both solutions A and B and sank in

solutions C and D. Samples of the garbage bag and Styrofoam Bowl

stayed afloat in all solutions. The Mac & Cheese container floated in

solutions C and D but partially sank in solutions A and B.

Data AnalysisFlame Test

When evaluated, the Sprite bottle turned out to be both green and clear while

also being soft and pliable. When burned, its flame possesses an orange color

and emits a black smoke. The shampoo bottle samples were white, opaque,

hard and rigid. When burned, their flames were orange and blue with no

smoke. The blister packs were clear and soft. They too had an orange and

blue flame, but the blister packs had a grayish smoke. Samples of the

garbage bag were white, opaque, soft, and pliable. Its flame was orange and

the smoke produced was white. The Mac and Cheese containers gave off a

yellow and purple flame with a blue smoke. They were also white, opaque,

hard, and rigid. Styrofoam samples, when burned, had yellow and orange

flames with very black smoke. In addition, the samples were hard, rigid,

opaque, and white.

Conclusion

• The solutions used to aid in determining density less than 0.91 g/ml. Plastics 2,3,4,5, and 6 had densities that ranged from 0.92

g/ml to less than 1.16 g/ml. This experiment was successful in narrowing down the

densities of the plastics to a range. Scientists can use an approximate density in order to

help narrow down the possibility of each unknown sample.