北师大版（2019）必修第二册Unit 5 Humans and nature Viewing Workshop 课件(共20张PPT)

(共20张PPT)
Unit 5
HUMANS AND NATURE
HOW BIG IS THE UNIVERSE
To read and talk about the universe
To view for understanding
To summarise information
UNIVERSE
stars
When it comes to universe, what do you know about it
galaxy
solar system
black holes
planets
infinite
vast
huge / giant
How big is the universe This video provides the answer to the frequently-asked question about the universe.
Probably, these words from the video are new to you. Guess their meanings. Have a try.
relating to or intended for one particular type of person or thing only
paying no attention to sth./sb.
to time a number, to increase by a large amount
a straight line from one side of a circle to the other side, passing through the centre
specifically
regardless of
multiply
diameter
surprisingly impressive or large
without limits
having the same value, purpose, job etc as a person or thing of a different kind
difficult or impossible to understand
equivalent
incomprehensible
bewildering
stupendous
infinite
confusing, especially because there are too many choices or things
What do you know about the universe Complete the quiz with the right numbers.
13.8 billion 27.5 billion 46 billion
1. The universe is about ____________ years old.
13.8 billion
2. The observable universe is about _________ light years across in diameter.
3. Today the distant objects like stars that we can observe are a bit more than _________ light years away.
93 billion
46 billion
Watch the first part of the video. Check your predictions from Activity 1.
Watch the rest of the plete the table.
1. How big is it
… the observable universe is currently 93 billion light years across.
The whole universe is probably infinite.
2. Is there an edge
The observable universe does.
…, and the whole universe has a temporal edge or what we call a beginning, but almost certainly not a spatial one.
3. Is there a center
The observable universe has a center—us.
We are at the center of the observable universe because the observable universe is just a region of space visible from Earth. Again, the observable universe does—you! The universe as a whole—almost certainly not.
4. Is it getting bigger
Yes, space is expanding, which makes
both the observable universe and the
whole universe bigger.
Questions Observable universe Whole universe
1. How big is it
2. Is there an edge
3. Is there a center
4. Is it getting bigger
The observable universe is about 93 billion light years across in diameter.
Infinite.
Yes. Temporal
edge.
No.
Yes. Earth/you.
No.
Yes.
Yes.
Watch the whole video again. Discuss the questions.
The size of the Earth within the observable universe is roughly equivalent to the size of a virus within the solar system. That does not help much, because we cannot really appreciate the incomprehensible smallness of a virus nor the bewildering bigness of our solar system either.
1. What is the Earth compared to Is the comparison useful in understanding the infiniteness of the universe
2. What methods does the presenter use to enable viewers to understand this piece of knowledge in physics
The presenter provides comparisons that are relative to our knowledge.
What have you learnt about the size of the universe
1. The universe is huge.
2. The observable universe is about 93 billion light years across in diameter.
3. The observable universe has a center.
4. Space has been expanding.
5. In the observable universe, the earth is roughly the size of a virus in the solar system.
6. Both the observable universe and the whole universe are becoming bigger.
7. The observable universe has an edge.
Find more information about the universe online and share with the class.