SKILLBUILDERHANDBOOKR15
2.7 Hypothesizing
HYPOTHESIZING means developing a possible explanation for historical events.
A hypothesis is an educated guess about what happened in the past or a prediction
about what might happen in the future. A hypothesis takes available information,
links it to previous experience and knowledge, and comes up with a possible
explanation, conclusion, or prediction.Understanding the Skill
STRATEGY: FIND CLUES IN THE READING.In studying the Indus Valley civilization,
historians do not yet know exactly what caused that culture to decline. They have,
however, developed hypotheses about what happened to it. Read this passage and look
at the steps that are shown for building a hypothesis. Following the passage is a chart
that organizes the information.STRATEGY: MAKE A CHART.
Applying the Skill
MAKE YOUR OWN CHART. Turn to Chapter 19, page 545, and read the Primary
Source. Predict what impact the introduction of firearms might have had on Japan.
Then read the surrounding text material. List facts that support your hypothesis
and what additional information you might gather to help prove or disprove it.Section 2: Higher-Order Critical Thinking
Identify the event, pattern, or
trend you want to explain.Determine the facts you have
about the situation. These
facts support various hypotheses
about what happened to the
Indus Valley civilization.Develop a hypothesis that
might explain the event.
Historians hypothesize that a com-
bination of ecological change and
sudden catastrophe caused the
Indus Valley civilization to collapse.Determine what additional
information you need to test
the hypothesis. You might refer to a book about India, for example,
to learn more about the impact of the Aryan invasions.4
3
2
1
Use a chart to summarize
your hypothesis about events.
Write down your hypothesis and
the facts that support it. Then
you can see what additional infor-
mation you need to help prove
or disprove it.2
Mysterious End to Indus Valley Culture
Around 1750 B.C., the quality of building in the Indus Valley cities declined. Gradually, the great
cities fell into decay. What happened? Some historians think that the Indus River changed course, as
it tended to do, so that its floods no longer fertilized the fields near the cities. Other scholars suggest
that people wore out the valley’s land. They overgrazed it, overfarmed it, and overcut its trees, brush,
and grass.
As the Indus Valley civilization neared its end, around 1500 B.C., a sudden catastrophe may have
had a hand in the cities’ downfall. Archaeologists have found a half-dozen groups of skeletons in
the ruins of Mohenjo-Daro, seemingly never buried. Their presence suggests that the city, already
weakened by its slow decline, may have been abandoned after a natural disaster or a devastating attack
from human enemies. The Aryans, a nomadic people from north of the Hindu Kush mountains, swept
into the Indus Valley at about this time. Whether they caused the collapse of the Indus Valley
civilization or followed in its wake is not known.2
1
3
4
HypothesisA combination of
ecological change
and sudden catas-
trophe caused the
Indus Valley civili-
zation to collapseFacts that support
the hypothesis- Building quality declined
- Indus River tended to
change course - Unburied skeletons were
found at Mohenjo-Daro - Aryan invasions occurred
around same time
Additional information needed- What was Indus Valley culture like?
- What were the geographical
characteristics of the region? - How did overfarming tend to affect
the environment? - What factors affected the decline of
other ancient civilizations?