Question 98
In this investigation, you will look at evidence that supports or contradicts hypotheses.
Work in groups of two or three.
Method
1 Read these facts.
• Tunguska is in northern Russia, far from any towns or cities. There is forest there, with many trees.
• In the morning of 30 June 1908 there was a very large explosion at Tunguska, between 5 km and 10 km above the ground.
• People living over 800 km away could see and hear the explosion.
• Vibrations from the explosion were recorded almost 5000 km away.
• The explosion flattened trees over an area of 2000 km².
2 Read these five hypotheses of what caused the explosion.
1 A comet impacting the Earth.
2 A type of volcano erupting.
3 Testing of a new type of bomb.
4 An alien spacecraft crashing.
5 An asteroid impacting the Earth.
3 Consider the evidence.
• All the trees that fell are pointing outwards from a central position.
• People discovered how to make very powerful bombs in 1945.
• No bomb this powerful has ever been made.
• Tunguska is very far from tectonic plate boundaries.
• Most comets break up higher than 10 km in the atmosphere.
• A small part of a comet is made from rock.
• Small rocky fragments have been found that show the signs of falling through the atmosphere at very high speed.
• No metal parts have been found at Tunguska.
Decide, using this evidence: which of the hypotheses are most likely.
Work in groups of two or three.
Method
1 Read these facts.
• Tunguska is in northern Russia, far from any towns or cities. There is forest there, with many trees.
• In the morning of 30 June 1908 there was a very large explosion at Tunguska, between 5 km and 10 km above the ground.
• People living over 800 km away could see and hear the explosion.
• Vibrations from the explosion were recorded almost 5000 km away.
• The explosion flattened trees over an area of 2000 km².
2 Read these five hypotheses of what caused the explosion.
1 A comet impacting the Earth.
2 A type of volcano erupting.
3 Testing of a new type of bomb.
4 An alien spacecraft crashing.
5 An asteroid impacting the Earth.
3 Consider the evidence.
• All the trees that fell are pointing outwards from a central position.
• People discovered how to make very powerful bombs in 1945.
• No bomb this powerful has ever been made.
• Tunguska is very far from tectonic plate boundaries.
• Most comets break up higher than 10 km in the atmosphere.
• A small part of a comet is made from rock.
• Small rocky fragments have been found that show the signs of falling through the atmosphere at very high speed.
• No metal parts have been found at Tunguska.
Decide, using this evidence: which of the hypotheses are most likely.
