Lesson 1
   Horsforth Commentary

Unit Title:  9D - PLANTS FOR FOOD
Caretaker: CLL/DH

Unit No   
9D

Lesson Title: Eat your Greens

NC Ref: 
Sc2 2a, 3a, 3e

Objectives:    Why are Plants so important as food for Humans

MK - food chains and food web construction. key words - producers, photosynthesis, food chain, glucose , respiration, starch

SK - energy is lost at each trophic level.  the shorter the food chain the more Energy is available. uses of glucose. key words - fat, oil, protein, cellulose

CK - little Energy is passed on from each trophic level. humans get more Energy from starch in plants than from meat.

Lesson outline: Horsforth Commentary

Before starting the topic pupils could be given some cress seeds and be asked to build something that will enable the seeds to grow to the best of their ability. the seeds could be split into two and half of them left out and the other half used in the"greenhouse". as the topic goes along, the pupils could add fertilisers in the appropriate lesson and so on. at the end of the topic, these seeds a=can be returned to to see what has happened to them. pupils could use knowledge gained throughout the topic to discuss.

Starter activities: recap on food chains and webs from previous topics. pupils could draw a food chain of the meal that they had last night. (they may need to work backwards to do this)

point out that all of the food that they ate originated from plants.

Main course: good chance to revise photosynthesis - ask question "how do plants make their own food?" elicit pupils ideas.

could hand out cards with each word on the photosynthesis equation including the symbols (+,          ). pupils could arrange the words to form the equation. More able pupils could be given the symbol equation.

CO₂ + H₂O        C₆H₁₂O₆ + O₂ + Energy

show pupils a plant and go through the parts of the plant . explain that humans utilise all parts of the plant for food. pupils use9Da/4

or show pupils a range of foodstuffs and ask them what part of the plant they come from

ask pupils if plants store glucose. plants store glucose as starch because it is insoluble and starch is converted back into glucose when needed.

possible practicals

1. testing for starch 9Da/1 9Da/3 - could test leaves (variegated and none variegated to show that chlorophyll is needed - the white parts of the leaf do not turn black)

could test potato for starch and discuss why it is there - store of energy. 

2. testing how much water is in fruit - good Sc1opportunity. 9Da/2. ask pupils what makes a "good "fruit. could investigate how much water is in different varieties of apples.  could relate back to inheritance and variation and talk about different varieties and different tastes

good opportunity to revise how the plant utilises glucose and how humans make use of these substances - could put pictures of foodstuffs and materials around the room (exploring science 9 - pg 37). ask pupils to stand next to the picture that they think is made by substances deriving from the plant  (e.g. fats and oils used to make perfumes)

Plenary:

Shout out some examples of food tuffs and pupils have to guess what part of the plant they come from.

Timings:

5 mins

15 mins

10mins

15 mins

10 mins

5 mins

Homework Suggestion:  produce concept map of all of the key words and equations involved in using plants for  food

Resources: cards with words and symbols for photosynthesis, different foodstuffs e.g. apple, wheat, potato. variegated and non-variegated leaves. iodine, water, pipettes, spotting tiles, test tubes, chopping board, knife, balance, microwave or pestle and mortar, filter paper, funnel, beaker, measuring cylinder, exploring science 9

Lesson 2 

Unit Title: Plants for food 
Caretaker: CLL/DH

Unit No   
9D

Lesson Title: Helping Crops to Grow

Horsforth Commentary

NC Ref: Sc2 3b, 5d,

Objectives:    

MK - fertilisers containing nitrates are added to crops to make them grow. weeds can prevent crops from growing well -fertiliser, nitrates, mineral salt

SK - mineral salts are released back into the ground by decomposers (fungi, bacteria and small animals). using too much fertiliser can harm these organisms - biomass, decomposer, compete

CK - nitrates are needed to make proteins. the role of other compounds (phosphate and potassium) on healthy plant growth. herbicides can kill weeds and leave crops untouched - herbicide, yield

Lesson outline: 

Starter activity:  ask pupils to imagine they are farmers. they need to come up with 2 things that might stop their crops from growing and thus loosing them money and 2 things that they could do to combat this. could do this as individuals or on groups. elicit pupils ideas as to the problems facing farmers and what they can do about it. introduce key words - fertiliser, weeds, mineral salts.

 
Main course:  discussion on fertilisers and what they do. why do farmers use them. they need to harvest as much crop yield as possible to make the most amount of money. farmers use fertilisers to put mineral salts back into the soil. could show pictures of a farm at work and talk about decomposition and decomposers putting mineral salts (nutrients) back into the soil.

chance to recap over last lesson on why plants need nutrients. they get nutrients from the soil through decomposers and fertilisers.

possible practicals

1.  which fertiliser is best? 9Db/1 use duckweed and fertilisers to see which fertiliser works best.

possible variations - using different fertilisers and the same concentration. using the same fertiliser and different concentrations. ensure the fertilisers are labelled and the contents of the fertilisers are clearly labelled. pupils can make predictions as to which one they think will work best and why.

THIS PRACTICAL WILL NEED TO BE ONGOING OVER 2 WEEKS.

2. Looking at fertilisers. provide pupils with different fertiliser labels and ask them to find out what is in the fertiliser and come to a conclusion about the suitability of the fertiliser and how cost effective it would be. ICT access would be useful so that pupils could research different fertilisers. (could include as h/w activity)

introduce key word - herbicide. ask pupils what they do. ask pupils what the advantages of using herbicides are. farmers gain higher yields because the herbicide selectively kills the weeds that compete with the crops. elicit pupils ideas about competition.

ask pupils what disadvantages there might be to using fertilisers and herbicides. herbicides can affect other organisms that live in the affected area and can have a knock on effect on the food chain. 9Db/6

Plenary: ask pupils to draw a table of advantages and disadvantages of using fertilisers.
 

Timings:

10mins

10 mins

10 mins

15 mins

15 mins

10 mins

Homework Suggestion: chose either for fertilisers (representative of a fertiliser company or farmers) or anti fertiliser (green peace) and come up with an argument to present to the class
 

Resources: selection of fertilisers, measuring cylinder, common duckweed, distilled water. fertiliser labels and leaflets
 

Lesson 3 

Unit Title:  plants for food
Caretaker: CLL/DH

Unit No   
9D

Lesson Title: problems with pests

Horsforth Commentary

NC Ref: Sc2 5a, 5e, 5f

Objectives:    

MK - Pests can prevent crops from growing well. pests can be killed using pesticides which can harm other organisms in the process - pests, pesticides

SK - pests compete with humans for food crops. pesticides can last for long periods of time -toxic, insecticide, persistent

 
CK - toxic chemicals can accumulate in a food chain. there are other methods that can be used to control pests such as biological control

Lesson outline: 

Starter activity: put  picture of a pest eating a plant on the board (examples in exploring science 9 - pg 40) ask pupils to answer some questions on the picture without giving them any help .

What is it?, Where is it?, why am I showing you this?, what has this got to do with plants for food?,

Go through some of pupils ideas - explain that they are going to be talking about pests. introduce definition of a pest and ask pupils why they are a problem
 
Main course: discussion and notes on what pests are and how farmers use pesticides to control them.

ask pupils to think of problems associated with using pesticides on a field or hedge. gain knowledge that pesticides can kill other useful organisms.

practical - opportunity to take pupils outside to demonstrate what happens in a food chain when species are killed. either clear a space in the classroom or take pupils to an open space. divide the class into groups and provide each pupil within each group a species within a food web.  either with string or by drawing on the floor create a food web of the organisms with the pupils standing in the right places. 9Dc/4 could be used to do this activity. the different effects of pesticides on a food web can be demonstrated by instructing pupils to sit down when their species is killed. pupils can predict what will happen to the rest of the organisms in the web. pupils could then answer questions on worksheet

or

Use food web game cards to do the same activity

introduce bioaccumulation -the effect of pesticides building up in a food chain.

you could arrange pupils in rows in the room in a pyramid form. each pupils is given a marble. state that the pupils are in a lake and the pupils at the bottom of the pyramid are plant plankton (might need explaining). the next row are animal plankton, the next, fish, the next fish eating birds.

this is a model to introduce bioaccumulation. tell pupils that the marbles are pesticide. animal plankton eats the plant plankton and so gain their marbles and so forth. at the end, the birds should have lots of marbles and so the pesticide has built up to a toxic level and kills the birds.

introduce other forms of control of pests - biological control.  give examples of biological control( exploring science 9 pg 42/3). discuss advantages of biological control over pesticides. ask pupils what they think the farmer has to think about before introducing other organisms - whether they with become pests, affect on other organisms etc.

Plenary: complete questions exploring science 9 pg 41/43
 

N.B could extend theses two lessons to a third lesson and have debate on the use of fertilisers and pesticides. this would need some planning. suggestion - in the previous lessons tell each pupil their role  e.g. green peace activist, farmer, employee of a fertiliser company etc. one person will have to chair the debate (teacher). the pupils could use the homework time and half of the third lesson  to prepare and the other half of the lesson could be used to debate the issues surrounding the use of fertilisers. this would be a good activity for more able pupils.

Timings:

10  mins

10 mins

20 mins

10 mins

10 mins

Homework Suggestion:  9Dc/6

Resources: exploring science 9, string\chalk, pictures of different organisms (could use ones on Dc/4), marbles
 

Lesson 4 

Unit Title:  plants for food
Caretaker: CLL/DH

Unit No   
9D

Lesson Title: Better Growth

Horsforth Commentary

NC Ref: Sc2 3a, 3c, 5a, 5d,

Objectives:    

MK - plants grow better in certain conditions (good supplies of light, warmth, moisture, mineral salts) the more the plant photosynthesises, the better it grows. greenhouses can be used the improve growth

SK - greenhouse environment can be controlled. increase in light intensity will increase the rate of photosynthesis. plant grow best at an optimum temperature. -optimum temperature

CK - changing environmental factors limits growth of plants. increase carbon dioxide concentration will increase the rate of photosynthesis.

Lesson outline: 

this can be spread over 2 lessons if wanted. you could discuss the idea of ideal conditions for growing plants and the use of greenhouses and then pupils could start to build their own green house.

this could be carried on to another lesson where temperature probes could be used to measure the temperature of the greenhouses and compare to plant growth

Starter activity: recap photosynthesis.

Main course: introduce idea that farmers can control the growth of the their plants and try to gain optimal growth through the use of greenhouses.

ask pupils what things need to be controlled in the greenhouse (think about photosynthesis). pupils may be able to suggest techniques for doing this. before making their own greenhouses pupils could design the best greenhouse using 9Dd/2.9Dd/3

practical - pupils could be given a list of materials that are available to them and ask them to design and build a greenhouse. explain that pupils are going to investigate how well the plants grow in different conditions within a greenhouse. the factor that the pupils will be monitoring is temperature using data logging equipment.

the class could be put into groups. half the groups create a greenhouse with an open space to simulate the plants being in the open. the other half create a greenhouse that is covered to simulate being inside the greenhouse (everything else must be kept the same).

or

pupils could make the same type of greenhouses but place them in different areas and the changes in temperature and plant growth can be logged.

after the experiment is complete - discussion about optimal factors and limiting factors (covered more in-depth at KS4)

Plenary: comparison of temperature and plant growth between the different types of greenhouses
 

Timings:

10 mins

15 mins

25 mins

Homework Suggestion: 
 

Resources: plastic bottle halves, cress or bean seeds, cling film, temperature probes, laptops