How plants grow

Click here to load reader

  • date post

    19-Mar-2016
  • Category

    Documents

  • view

    216
  • download

    1

Embed Size (px)

description

1F How plants grow

Transcript of How plants grow

  • Howplantsgrow.notebook

    1

    April06,2012

    How plants grow

    Starter activity:

    3 mins

    Brainstorm - Where do plants get their food?

  • Howplantsgrow.notebook

    2

    April06,2012

    Food in plants

    maketheirown

    photosynthesis

    air

    water

    carbondioxide

    lightenergy

    nutrientsinsoil

  • Howplantsgrow.notebook

    3

    April06,2012

    What types of food groups do you know?

    Plants make food

    write your answers here:

    Protein

    Starch

    Fat

    Minerals

  • Howplantsgrow.notebook

    4

    April06,2012

    Carbohydrates - Starch

    What do you know about starch?

    Starch

    carbohydrateturnsiodinepurple/darkblue

    Storageofenergy

  • Howplantsgrow.notebook

    5

    April06,2012

    How to test for starch in a leaf

    Heat a beaker of water Take a leaf and place it in the hot water for 1

    minute to soften it Place the leaf in hot ethanol until the leaf loses

    it's colour Rinse the leaf in hot water to soften it Place the leaf on a white tile Test the leaf with iodine solution

  • Howplantsgrow.notebook

    6

    April06,2012

    X

    XX

    XXXX

    XX

    XXX

    Ethanol

    Leaf

    X

    XX

    XXXX

    XX

    XXX

    HEAT

    Testing a leaf for Starch

    1

    2

    WARNING:

    ETHANOL IS FLAMMABLE, DO NOT USE THE

    BUNSEN WITH ETHANOL NEAR IT!

  • Howplantsgrow.notebook

    7

    April06,2012

    Iodine Solution

    Tile

    Leaf

    Iodine

    Before

    Iodine

    After

    Brown/ orange

    purple/ dark blue

    / black

    Test for Starch

    *A positive test is when the iodine changes colour as a result of the presence of starch

  • Howplantsgrow.notebook

    8

    April06,2012

    An example of a leaf test

    After iodine solution is added to the leaf, the following may be observed:

    Where are the positive results?

  • Howplantsgrow.notebook

    9

    April06,2012

    Plenary:

    What was the purpose of putting the leaf in:

    a) boiling waterb) ethanol?

    Homework:

    Write a brief summary of your experiment today. What did you find out?

  • Howplantsgrow.notebook

    10

    April06,2012

    Air and plants

    Objective:

    To know how oxygen and carbon dioxide affect plant growth

    Read the following text and discuss the answers in groups. Be ready for class discussion

  • Howplantsgrow.notebook

    11

    April06,2012

  • Howplantsgrow.notebook

    12

    April06,2012

  • Howplantsgrow.notebook

    13

    April06,2012

    The following experiment can be set up to show what happens when a leaf only has certain elements available

    What do you think the results of a starch test will be for each leaf?Give reasons for your answers

    Leaf A will produce a positive/ negative because...........Leaf B will produce a positive/ negative because...........Leaf C will produce a positive/ negative because...........

  • Howplantsgrow.notebook

    14

    April06,2012

    So, the word equation for photosynthesis is:

    carbon dioxide + water starch sunlight energychlorophyll

    Summary:

    Leaves produce starch when they are exposed to light, water and carbon dioxide.

    Or is there more?

  • Howplantsgrow.notebook

    15

    April06,2012

    Plants also give out a gas when the photosynthesise

  • Howplantsgrow.notebook

    16

    April06,2012

    Investigating gas production by plants

    You are going to investigate how light affects the rate of gas production in pond weed.

  • Howplantsgrow.notebook

    17

    April06,2012

    Sc1 Skills

    What do we know about scientific method?

  • Howplantsgrow.notebook

    18

    April06,2012

    Prediction Hypothesis

    Fair test Apparatus

    Method Safety

    Results Conclusion

    Evaluation

  • Howplantsgrow.notebook

    19

    April06,2012

    Prediction: Should relate two factors and state what happens to one if the other is changed

    Hypothesis: The science facts you know related to the topic

    Fair test: How you make sure you only change one factor

    Apparatus: What basic hardware you used

    Method: Bullet points of what you did

    Safety: Basic lab rules

    Results: What you found out in a clearly presented way

    Conclusion: What you results show, relating to any patterns

    Evaluation: How you could do your investigation better

  • Howplantsgrow.notebook

    20

    April06,2012

    Factors (also called variables)

    Independent variables

    Dependent variables

    What do you understand by the following terms?

    Thisisusuallywhatwechoosetotest

    Thisiswhatchangesasaresultofuschangingtheindependentvariable

  • Howplantsgrow.notebook

    21

    April06,2012

    Examples:Pendulum

    Independent variables

    Dependent variables

    lengthofstring

    timetakenforswing

  • Howplantsgrow.notebook

    22

    April06,2012

    acid

    water

    sodium

    thiosulphate

    Rates of reaction

    Dependent variables

    Independent variables

    1.concentrationofacid

    2.temperatureofchemicals

    timetakentoreact

  • Howplantsgrow.notebook

    23

    April06,2012

    Prediction - linking dependent and independent variables

    If .................... changes, then ................... will happen.

    If independent variable changes, dependent variable will result

    Think about the examples we have looked at. Now write a prediction for the pondweed.

    Independent variable = light intensity

    Dependent variable = gas production (bubbles of gas)

    Examples:

    If the length of the string increases, then the time taken for the swing will increase

    If the concentration of the acid increases , then the time taken for reaction will decrease

  • Howplantsgrow.notebook

    24

    April06,2012

    If the light intensity increases , then the time taken for gas to be produced will decrease

    Check your prediction against mine:

  • Howplantsgrow.notebook

    25

    April06,2012

    Hypothesis: This is your chance to shine!

    What topics do you need to cover?How much detail?

    Write a paragraph of 3 - 4 sentences that explains what you know about:

    What food plants makeWhat things plants need to make their own foodHow we can test this food is present

  • Howplantsgrow.notebook

    26

    April06,2012

    Example hypothesis:

    Plants store their food as starch. In order to do this they need sunlight energy, water and carbon dioxide. The leaves absorb carbon dioxide and water and store the starch. We can test for the presence of starch by using iodine solution which will turn dark blue/ purple if it is present.

  • Howplantsgrow.notebook

    27

    April06,2012

    Fair tests:

    water

    sodium

    thiosulphate

    temperature

    concentration

    surface area

    stirring

    volumes of

    reagents

    acid

    What should we do to make a fair test?

    How do we make this a fair test for the pondweed?

    Change only one factor at a time

  • Howplantsgrow.notebook

    28

    April06,2012

    Method: How much detail should you include?

    Write 2 methods

    Method 1 - short, 5 steps

    Method 2 - detailed, 10 steps

    How much do you really need to say?What is necessary in a method?

    We all know how to make a sandwich. So, if I said to you that I wanted a method on how to make a cheese sandwich, how much detail would you use?

    Take 2 slices of bread Butter the bread Add cheese Put the slices together Serve

    Walk to the kitchen Wash hands Take bread Open bag Take out 2 slices Place on clean work surface Use 2g of butter for the bread Add 5 g cheese Put slices together Serve

    Do I need all of these steps?Which ones are useful? Why?

    Detailed methods are good but only if the right details are added

  • Howplantsgrow.notebook

    29

    April06,2012

    Apparatus:

    2-D neat diagrams, of a page.Use sharp pencil and a ruler

    How much information should you include?

  • Howplantsgrow.notebook

    30

    April06,2012

    Safety:

    What are basic safety rules in the lab?

  • Howplantsgrow.notebook

    31

    April06,2012

    Results:

    What do want to show?What should a good results section contain? How many results do I need?Do I need repeats and average numbers?

    How much information should I include?

  • Howplantsgrow.notebook

    32

    April06,2012

    http://www.saddleworth.oldham.sch.uk/science/simulations/waterweed.htm

  • Howplantsgrow.notebook

    33

    April06,2012

    dependent variable

    independent variable

    Light intensity

    bubble count

    x

    y

    0 100

    35Hints for a good graph:

    If you can't remember the axis labels. 'X' is a-cross, so put it on the axis that goes across

    Start at 0 for each axis Use regular intervals for your scales Choose a scale that is easy to read Look where the independent variable goes Try to use the whole page to draw your graph

  • Howplantsgrow.notebook

    34

    April06,2012

    Light intensity (units)

    Bubble count

    0 1 2 3 4 5 6 7 8 9 100

    5

    10

    15

    20

    25

    30

    35

    Rate of photosynthesis

    estimating missing values

    What do you notice about my 'line of best fit'? Is it straigh