[填空题]
Much of plastic pollution is nofl h;va ng(,s;n-biodegradable, which means it persists in 0-yx .(jps)7os uyr cathe environment for long periods of time. Macroplast)7o-x sr .y juy(a0scpic pollution is defined as plastic debris that is larger than 1 mm and microplastic pollution less than 1mm.
On a field trip to a local beach in a temperate climate, students were asked to collect samples of sand and measure the number of pieces of plastic debris present. To do this, 5g samples of sand were collected and placed in a beaker. 50 ml of a concentrated salt solution was then added to the samples, which caused plastic debris to float to the surface. Plastic debris was removed from the samples, measured, and categorised, and the results were recorded in a table. The experiment was repeated in another school in a tropical climate, and the results were compiled.
1.1.Identify one controlled variable from the methodology.
1.2.Suggest the importance of having a standard classification for plastic debris in this investigation.
2.1.Calculate how many times greater the mean number of microplastic debris sampled was in the tropical climate compared to the temperate climate.
The number is .
2.2.State which uncontrolled variable is most likely responsible for the higher numbers of microplastics sampled compared to macroplastics in the tropical climate. Give a reason for your answer.
3.Students in both climates noted the varying sand particle size of the sand samples taken at each beach.
3.1.Describe a limitation to the methodology based on this information.
3.2.Suggest a method to reduce the variability in particle size.
4.Evaluate the use of microplastic and macroplastic categories in this investigation.
