Unit 6 In the Laboratory
1.Listen,read and practice in pairs.
Do you like to do experiments in a laboratory?
What is a science class like? Let's see what these people are doing.
Teacher:Good morning,everyone.
In this experiment we'll observe seeds as they develop into plants.
Now,watch me closely.First....(The teacher shows the strdents all the steps)
OK,it's your turn
Work in groups of three and get the things you need from the front.
LiMeng:Peter,I'll go and get them...
Here you are,two dishes,some seeds and a piece of cotton wool.
Peter:Good.I want to see what the seeds look like under the microscope.
Daniel:I'm sure they'll look pretty big.
Let us have a look too after you finish.
Peter:I can't see them clearly.Is there anything wrong with this microscope?
LiMeng:Let me do it.I know how to work this thing.
Teacher:How are you doing here?Need some help?
Daniel:We're fine,Sir.
LiMeng:I've got them.You need to turn this knob very slowly,you know.
Daniel:I think we need to put the seeds in the dishes quickly now.
Peter:Wait.What's Step One?Lay some cotton wool in the dishes.
Sprinkle water over the cotton....
5.Listen,read and answer.
LiMeng is now worried about his seeds in the lab.
He needs to go there every day to check their growth.
LiMeng:Daniel.Look at the shoots.Where's our ruler?
Let me take one out and you measure them.Now,do it gently.
Daniel:OK,write this down:
the shoot is 3mm(millimetres)in height and the root is 1 mm in length.
LiMeng:This is Day 5,isn't?
Daniel:Don't forget to put in your notes the colour and shape of these shoots.
LiMengL:Yeah.It's all here.I wish I could grow grow as fast as these shoots.
Daniel:I've got an idea.Why don't we do another experiment at the same time.
We can measure how quickly you grow and report to your mum.
LiMeng:Will you stop it?It'd take you years to finish that one.
On second thoughts,it might be a good idea to see how tall I am now.
My trousers all seem to be short lately.
Daniel:We'll have to do that when we get back home,
but I'm sure you must be over 5 feet 10 now.
7.Listen,read and discuss.
Gregor Mendel
Growing plants in the school laboratory can be fun and interesting.
Have you ever tried such an experimen?
If you haven't,don't worry.You may have a chance to do it in the future.
A man who became very famous by growing plants was Gregor Mendel.
He was a scientist and it was his study of peas that helped other scientists
and now many other people,
to understand some important new things.
Gregor Mendel was born on July 22,1822 in a small town in a country
which is now called the Czech Republic.
His parenhts were not rich so he was not able to go to school.
When he was young,his parents taught him to read and write.
He also learnt how to grow fruit trees in his father's garden.
He loved growing plants.
He became very interested in trying to grow flowers
which were of the same beautiful colour.
He tried to do this in many different ways and he wrote down exactly what he did.
He did many experiments like this
and he always wrote down exactly what hqppened in his experiments.
As he grew older,Mendel wanted to learm more.
He became a monk and was then able to study at a university.
He grew peas in the garden at the monastery and by carefully breeding his pea plants,
he found a way to grow mostly smooth round peas instead of lumpy and wrinkled peas.
He also found a way to grow taller pea plants instead of shorter pea plants.
Scientists have used his ideas about breeding
to grow apple trees which have bigger apples on them.
They have also used Mendel's ideas to feed cattle which grow thaller and heavier.
Mendel's ideas helped us to understand why two parents will have a child whoi for example,
is tall or has blonde hair.
Mendel's work helps us to study an important part of science
which is called genetics.
10.Listen,read and practice in pairs.
Have you ever written lab reports?
What do you have to put down in a lab report?Let's see what xiaohong is asking.
Xiaohong:What are you drawing there,LiMeng?
LiMeng:A graph showing how quickly the wheat shoots grow.
Don't talk to me now,or I'll make a mistake.
Xiaohong:Well,I'm sorry but what are you counting there?
LiMeng:OK.It's like this.I need to show how long the shoots are each day.
For these ten days,I need to mark their heights.
Xiaohong:But these are just some dots,not a graph.
LiMeng:I haven't quite finished yet.When I link up these dots,what do I get?
Xiaohong:I see.But what do you need the graph for?
LiMeng:It's part of a lab report we've got to write.
See here?Aim,materials and method.We've got to follow these six steps closely.
Xiaohong:That's interesting.It's just like one of my recipes.
LiMeng:Recipes?This is science.Anyway,can I finish this first?