Sea-floor spreadingA summarising activity

First, the reading

• Read through once to get the overall picture of what the article is about– Pause every now and then to check that you

understand– Be sure to look at pictures and captions and

understand how they relate to the text– Use a code system: eg “def” for definitions, “fact”

for facts, “A” for scientific arguments, “C” for cause and effect statements, etc

Summarising

• pull out main ideas • focus on key details • use key words and phrases • break down the larger ideas • write only enough to convey the gist • take succinct but complete notes

How do you do it• Who, what, where, when and how????• Take out material that is not important to your

understanding.• Take out anything that is repeated.• Replace lists of things with a word that describes the

list (e.g., use fish for rainbow trout, salmon, and halibut).

• Select a topic sentence or invent one if it is missing.• Note any new words and their meanings.

5

The word photography comes from the Greek word meaning “drawing with light”….Light is the most essential ingredient in photography. Nearly all forms of photography are based on the fact that certain chemicals are photosensitive- that is, they change in some way when exposed to light. Photosensitive materials abound in nature; plants that close their blooms at night are one example. The films used in photography depend on a limited number of chemical compounds that darken when exposed to light. The compounds most widely used today are called halogens (usually bromine, chlorine, or iodine).

Microsoft Encarta Encyclopedia

6

The word photography comes from the Greek word meaning “drawing with light”….Light is the most essential ingredient in photography. Nearly all forms of photography are based on the fact that certain chemicals are photosensitive- that is, they change in some way when exposed to light. Photosensitive materials abound in nature; plants that close their blooms at night are one example. The films used in photography depend on a limited number of chemical compounds that darken when exposed to light. The compounds most widely used today are called halogens (usually bromine, chlorine, or iodine.

Microsoft Encarta Encyclopedia def

defPhoto = lightGraph = drawing

Photo = lightsensitive

So, we end up with:

• Photography = “drawing with light”• Light is the most essential ingredient in

photography. • Photosensitive – change in some way when

exposed to light• Photography depends on chemical

compounds that darken when exposed to light.

• Dot points are fine in a summary• Make sure you rewrite things in your own

words wherever possible

So, our final summary could be:

• Photography depends on light to darken photosensitive chemicals in the film.

A summary is:

• An essential condensation in your own words.• Answers the question “what is the author

really saying?”• Is the result of careful “listening” to the

author.• Remains faithful to the author’s emphasis and

interpretation.• Does not disagree with or critique the author’s

opinion.

Anticipation

• What information do you think will be given in the article on sea floor spreading?

3-2-1

• 3 Things you found out

• 2 Things you found interesting

• 1 Question you still have

Questions to answer

1. Why did Wegner not know about sea-floor spreading?2. Which new technologies made the discovery and verification

of sea-floor spreading possible3. List, in point form, the evidence of sea-floor spreading4. Explain how the evidence listed in Q3 supports the theory of

sea-floor spreading5. Describe how sea-floor spreading supports Wegner's theory

of continental drift6. The word paleomagnetism is made of two parts.

a. What are they?b. What do they mean?