Tar: A Thick Black Sticky Substance
Tar is a thick black sticky substance that has been used for centuries in construction, waterproofing, road paving, and even medicinal applications.
What is Tar Made Of?
Tar can be derived from coal, wood, or petroleum, each type having distinct properties and applications.
How is Tar Made?
The process of making tar involves heating organic material to extract the desired compounds, known as pyrolysis, which is the thermal decomposition of organic material in the absence of oxygen.
Types of Tar
- Wood Tar: produced by slowly heating wood in a low oxygen environment, used for waterproofing and medicinal applications.
- Coal Tar: obtained through the destructive distillation of coal, used in road construction, roofing, and as a wood preservative.
- Petroleum Tar: derived from crude oil, used in road construction, waterproofing, and as a binding agent in asphalt.
History of Tar
Tar has been used for thousands of years, with ancient civilizations such as the Mesopotamians and Egyptians using natural bitumen for waterproofing and medicinal purposes.
Environmental Impact
The production of tar, especially coal tar and petroleum tar, has environmental implications, including the release of pollutants and greenhouse gas emissions.
Sustainable Alternatives
Industries are exploring alternative materials and sustainable production methods, such as biobased alternatives and recycling technologies, to reduce the environmental impact of tar production.
Conclusion
Tar remains an essential material in modern society, with its waterproofing properties making it indispensable in roofing, road construction, and industrial applications.
Key Vocabulary
| Term | Definition | Example Usage |
|---|---|---|
| Tar | A thick black sticky substance used in construction, waterproofing, and medicinal applications. | Tar is used for roofing to prevent water leakage. |
| Pyrolysis | The thermal decomposition of organic material in the absence of oxygen. | Pyrolysis is used to extract tar from organic materials like wood and coal. |
| Wood Tar | A type of tar produced by slowly heating wood in a low oxygen environment. | Wood tar is used for medicinal applications and waterproofing ships. |
| Coal Tar | A type of tar obtained through the destructive distillation of coal. | Coal tar is used in road construction and as a wood preservative. |
| Petroleum Tar | A type of tar derived from crude oil. | Petroleum tar is used in road construction and as a binding agent in asphalt. |
| Bitumen | A natural substance used for waterproofing and medicinal purposes. | Ancient civilizations used natural bitumen to waterproof their ships and buildings. |
| Biobased Alternatives | Sustainable materials derived from biological sources, used as alternatives to traditional tar. | Biobased alternatives are being explored to reduce the environmental impact of tar production. |
| Destructive Distillation | A process of heating a material in the absence of air to extract its components. | Destructive distillation is used to obtain coal tar from coal. |
Watch The Video
Vocabulary Quiz
1. Which process is involved in making tar?
A) Oxidation
B) Pyrolysis
C) Distillation
D) Fermentation
2. What is the primary use of Wood Tar?
A) Road construction and roofing
B) Waterproofing and medicinal applications
C) Binding agent in asphalt
D) Wood preservative
3. Which of the following is a type of tar derived from crude oil?
A) Coal Tar
B) Wood Tar
C) Petroleum Tar
D) Natural Bitumen
4. What is the environmental impact of tar production, especially coal tar and petroleum tar?
A) Release of oxygen and reduction of greenhouse gas emissions
B) Release of pollutants and reduction of greenhouse gas emissions
C) Release of pollutants and greenhouse gas emissions
D) No environmental impact
5. What are industries exploring to reduce the environmental impact of tar production?
A) Increasing coal tar production
B) Decreasing petroleum tar production
C) Alternative materials and sustainable production methods
D) Discontinuing the use of tar
Answer Key:
1. B
2. B
3. C
4. C
5. C
Grammar Focus
Grammar Focus: The Use of the Present Perfect Continuous Tense
Grammar Quiz:
- Which of the following sentences correctly uses the present perfect continuous tense to describe an action that started in the past and continues up to the present?
A) Tar was used for centuries in construction.
B) Tar has been used for centuries in construction.
C) Tar is used for centuries in construction.
D) Tar will be used for centuries in construction.
- What is the correct form of the present perfect continuous tense for the verb “explore” in the sentence: “Industries ____________________ alternative materials and sustainable production methods”?
A) explore
B) have explored
C) are exploring
D) have been exploring
- Choose the correct sentence that uses the present perfect continuous tense to describe the ongoing production of tar:
A) The production of tar was stopped due to environmental concerns.
B) The production of tar has been stopped due to environmental concerns.
C) The production of tar is being stopped due to environmental concerns.
D) The production of tar has been continuing despite environmental concerns.
- Which sentence correctly uses the present perfect continuous tense to describe the ongoing use of coal tar in road construction?
A) Coal tar was used in road construction for many years.
B) Coal tar has been used in road construction for many years.
C) Coal tar is used in road construction for many years.
D) Coal tar will be used in road construction for many years.
- What is the correct form of the present perfect continuous tense for the verb “use” in the sentence: “Ancient civilizations ____________________ natural bitumen for waterproofing and medicinal purposes”?
A) use
B) have used
C) are using
D) have been using
Answer Key:
- B) Tar has been used for centuries in construction.
- D) have been exploring
- D) The production of tar has been continuing despite environmental concerns.
- B) Coal tar has been used in road construction for many years.
- B) have used