Casa ESL · B1 Intermediate · Unit 17 of 20 · Step 2
Scientific topics and advanced article usage
Name
Date
Vocabulary
experiment
nounA scientific test done to find out what happens under certain conditions.
"The experiment proved that the theory was correct."
hypothesis
nounAn idea or explanation that you then test through study and experiment.
"A good scientist always starts with a hypothesis."
evidence
nounFacts or signs that show something is true.
"The evidence suggests that climate change is accelerating."
species
nounA group of animals or plants that are similar and can reproduce together.
"Scientists discovered a new species of frog in the Amazon."
breakthrough
nounAn important development or discovery.
"The breakthrough in medicine could save thousands of lives."
analyse
verbTo examine something in detail to understand it.
"Researchers need to analyse the data before publishing results."
renewable
adjectiveAble to be replaced naturally and used without running out.
"Solar power is a type of renewable energy."
microscope
nounAn instrument that makes very small things look larger.
"She looked at the cells under a microscope."
Grammar Focus
Articles — a, an, the, zero article (advanced uses)
Use 'a/an' for first mention or non-specific singular countable nouns. Use 'the' for specific or previously mentioned nouns, unique things (the sun, the internet), superlatives, and with 'of' phrases (the University of Oxford). Use zero article for general plural or uncountable nouns (Water is essential), most country names, languages, meals, and academic subjects.
A scientist in Japan made an important discovery. The discovery was published in a leading journal.
The Earth revolves around the Sun.
Water is essential for life. (zero article — general statement)
She studies biology at the University of Melbourne.
Exercises
Exercise 1
Complete each sentence with 'a', 'an', 'the', or '—' (no article).
1. researchers at university have made important discovery.
2. Moon orbits Earth every 27 days.
3. She is studying chemistry because she wants to become scientist.
4. They published results in International Journal of Physics.
5. climate change is most serious challenge facing world today.
Exercise 2
Choose the correct option to complete each sentence.
1. She works at ___ hospital in the centre of town.
2. ___ information in the report was very useful.
3. He wants to study ___ medicine after finishing school.
4. It was ___ best experiment we had ever conducted.
5. ___ scientists believe that ___ Mars may have had water.
Reading
A New Discovery in the Ocean
An international team of marine biologists has discovered a new species of fish in the Pacific Ocean. The fish was found at a depth of over 2,000 metres during an expedition led by the University of Hawaii. The species is unusual because it produces its own light — a phenomenon known as bioluminescence. Scientists believe the discovery could help them understand how life survives in the deepest parts of the ocean. Research on deep-sea creatures is still in its early stages. Much of the ocean remains unexplored, and experts say that thousands of unknown species may still be waiting to be found. The team plans to return to the area next year to continue their work.
1. What is unusual about the newly discovered fish?
2. Why do scientists think this discovery is important?
Speaking
Discuss these questions with a partner or your teacher.
Writing
Write 6–8 sentences about a scientific topic that interests you. Pay careful attention to your use of articles (a, an, the, or no article).
Example: I am very interested in space exploration. The idea of travelling to Mars fascinates me. Scientists at NASA have been working on a programme to send people to the planet. Space travel requires an enormous amount of research and technology.
Answer Key — For Teacher Use
Exercise 1
1. — / the / an · 2. The / the · 3. — / a · 4. the / the · 5. — / the / the
Exercise 2
1. a · 2. The · 3. — · 4. the · 5. — / —
Reading Comprehension
1. The fish produces its own light, a phenomenon known as bioluminescence. · 2. They believe it could help them understand how life survives in the deepest parts of the ocean.