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Starter

You are planning an investigation into the growth of plants. You are changing the amount of water and measuring how long the shoots grow.

  • What is the independent variable?
  • What is the dependent variable?
  • What would an aim be for this experiment?

Extension: How would you increase the reliability of this experiment?

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Life on Earth

Nat 4 Unit 3

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Today we will…

Learning Intention:

To investigate fertilisers

Success Criteria:

  • I can describe what fertilisers are
  • I can explain why fertilisers are used
  • I can describe the effects of fertiliser
  • I can state alternatives to fertiliser
  • I can safely carry out an experiment
  • I can identify different variables in an experiment

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What are fertilisers?

Fertilisers contain the nutrients that plants need to grow.

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Fertiliser is added to the soil. Plants absorb the nutrients through their roots.

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Plants grown with fertilisers are bigger and grow faster.

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What are fertilisers?

Plants need lots of nutrients to grow. The three main nutrients are:

  • Nitrogen
  • Phosphorous
  • Potassium

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Today we will…

Learning Intention:

To investigate fertilisers

Success Criteria:

  • I can describe what fertilisers are
  • I can explain why fertilisers are used
  • I can describe the effects of fertiliser
  • I can state alternatives to fertiliser
  • I can safely carry out an experiment
  • I can identify different variables in an experiment

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Why are fertilisers used?

Fertilisers can be used to improve crop yields (the amount of crop made). Farmers add fertilisers to replace the lost soil nutrients from harvesting crops.

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When crops are harvested, the crop is removed and the nitrogen it contains is taken out of the field’s natural nitrogen cycle.

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Why do plants need nutrients?

  • What do plants use nitrogen for?

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  • Why do plants need magnesium?

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  • Why do plants need potassium?

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  • What do plants need phosphorus?

to make proteins

to make chlorophyll

to grow and support their immune system

for energy transfer, to grow properly

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Today we will…

Learning Intention:

To investigate fertilisers

Success Criteria:

  • I can describe what fertilisers are
  • I can explain why fertilisers are used
  • I can describe the effects of fertiliser
  • I can state alternatives to fertiliser
  • I can safely carry out an experiment
  • I can identify different variables in an experiment

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Impact of fertilisers

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Eutrophication

  • Fertilisers are washed into rivers and lakes
  • Increase in nutrients causes an algal bloom.
  • The algal bloom blocks sunlight so water plants can’t photosynthesise and die.
  • Bacteria break down the dead plants and use up the oxygen in the water.
  • Lack of oxygen causes the death of other organisms in the rivers.
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Today we will…

Learning Intention:

To investigate fertilisers

Success Criteria:

  • I can describe what fertilisers are
  • I can explain why fertilisers are used
  • I can describe the effects of fertiliser
  • I can state alternatives to fertiliser
  • I can safely carry out an experiment
  • I can identify different variables in an experiment

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Alternatives to chemical fertilisers

Alternative methods can be used to reduce the harm to the environment.

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Manure

Growing clovers and ploughing it back into the soil.

Compost

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Checkpoint Questions

  • Why do farmer need to use fertilisers?
  • What is an alternative way of naturally fertilising the soil?
  • What 3 elements do artificial fertilisers contain?
  • What is the problem that artificial fertilisers cause in local ponds and lakes?
  • How does this affect the organisms that live in the water?

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Today we will…

Learning Intention:

To investigate fertilisers

Success Criteria:

  • I can describe what fertilisers are
  • I can explain why fertilisers are used
  • I can describe the effects of fertiliser
  • I can state alternatives to fertiliser
  • I can safely carry out an experiment
  • I can identify different variables in an experiment

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Planning Your Experiment

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1.Aim

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a. What is the result you are measuring?

2. Independent variable

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b. How you doing the experiment

3. Dependant variable

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c. What is the question you are trying to answer?

4. Control variables

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d. How would you improve your experiment

5. Method

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e. What it the thing you are changing?

6. Results

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f. Where you put your results

7. Conclusion

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g. Things you need to keep the same for each experiment

8. Evaluation

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h. Use your results to answer the aim

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Investigating the Effect of Fertiliser

Aim: to investigate how __________ affects growth of _________ seeds.

Independent variable:

Dependent variable

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Method

Water

Fertiliser

  • Lay the cotton wool flat in the deeper petri dish
  • Wet one cotton pad using the water from your beaker. It should be wet but not soaking.
  • Put 20 seeds on the cotton wool
  • Put the shallow lid on top.
  • Write your initials and a W around the edge on the lid as small as you can.
  • Repeat for your second dish using fertiliser instead of water.
  • Label this dish with an F.

Write an equipment list.

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Starter

  • What experiment did you set up last week?
  • What is the independent variable?
  • What is the dependant variable?

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Results

  • Collect your seeds.
  • Select one shoot from each petri dish to measure the length of. Record these results in your results table.
  • Tidy your experiment:
  • Cotton wool and seeds go in the bin
  • Petri dishes are washed

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Conclusion

Answer the question from you aim - what effect did fertiliser have on your seeds?

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Evaluation

Did your experiment work?

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How could you improve your experiment?

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Today we will…

Learning Intention:

To investigate fertilisers

Success Criteria:

  • I can describe what fertilisers are
  • I can explain why fertilisers are used
  • I can describe the effects of fertiliser
  • I can state alternatives to fertiliser
  • I can safely carry out an experiment
  • I can identify different variables in an experiment

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Blue Flag Beaches

Your task is to research the following:

What is a ‘Blue Flag Beach?’

How do they measure whether or not it is safe to swim in the water?

What are the other types of grading for beaches?

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Write a conclusion – Do you think these awards are important? Why do you think this?

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