III Vocabulary practice. Fill in the words from exercise II into the gaps below. Change the word forms if necessary.

• The satellite _______ atmospheric gases responsible for ozone destruction.

• A baseball in flight is subject to ________, which impedes the its motion through the air.

• The vibrations of the gong ______ through the temple.

• Most ______ _______, such as rain, are relatively harmless so far as humans are concerned.

• For periodic waves, _______ has an inverse relationship to the concept of wavelength; simply, frequency is inversely proportional to wavelength λ.

IV Answer the questions:

1. How does infrasound affect the human body? Can you give any examples?

2. How did the scientist come to his conclusion? What helped him to make it?

3. According to the article, what is the explanation to the paranormal phenomena? Do you agree with it?

4. In what circumstances can infrasound occur?

V Speaking. You are Vic Tandy giving a report for the Society of Physical Researches. Your speech should be clear and convincing.