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TDU 13: Practical investigations: exploring seed germination

Introduction

Elementary science is not just about gaining subject knowledge, but also about exploring, discovering, hypothesising and testing. It is only by doing practical investigations students will develop a true understanding of the world around them and begin to discriminate scientific claims and facts. Your role as a science teacher is to provide opportunities for your students to experience the excitement of carrying out investigations and solving simple problems for themselves. This unit will focus on ways of incorporating a long-established experimental technique called the scientific method into the elementary classroom.

Learning outcomes

After studying this unit, you should be able to:

  • plan a practical investigation that explores seed germination using the scientific method

  • identify other practical applications of the scientific method in the elementary science classroom.

1 The scientific method

Science is ultimately based on observing. Observations lead to questions, and questions then lead to experimentation, in an attempt to produce convincing answers. The scientific method (Figure 1) refers to a series of steps that, when followed, can provide reliable answers to questions in the field of science.

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Figure 1 The scientific method

The scientific method is not reserved for trained scientists. It can be easily applied to everyday classroom contexts – even those with limited resources. Figure 2 is a flow chart of the steps to be followed in the scientific method.

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Figure 2 Following the scientific method

Pause for thought

  • What is your understanding of each of the steps?
  • What are the benefits of using the scientific method with your students?
  • What challenges does it pose to you as the teacher?
  • In what ways could the scientific method be used in your elementary science classroom?

Resource 1 provides a more detailed description of the scientific method, while Resource 2 explains what is meant by the term ‘fair test’.

2 The scientific method in the everyday science classroom

Students are fascinated by the world around them. They naturally observe and explore their surroundings and ask questions to make sense of things. Such curiosity provides teachers with many opportunities to facilitate meaningful learning experiences.

The basic steps of the scientific method can be introduced and used with students from a young age. The list below discusses some of the ways that the scientific method can be applied in the everyday science classroom. It is not necessary to use all the steps every time you undertake an investigation in your classroom. It is possible to use the scientific method flexibly.

  1. Question/problem: Questions drive the scientific method. As students begin to explore a new concept or topic they will ask questions. Some of these questions can be used as a basis for investigation such ‘Can plants grow without soil?’ Students may produce questions like these during a brainstorming session or they could be encouraged to generate questions by completing a statement such as ‘I wonder…’
  2. Observation/research: The opportunities to promote observation skills in the school environment are almost limitless. By planting different types of seeds in pots, students can observe the plant life cycle directly themselves. By standing outside, students can observe how shadows are cast. By looking inside their own mouth, and those of other students, students can observe the similarities and differences between people's teeth.
  3. Form a hypothesis: You should use open-ended questions to encourage guessing and prediction. Examples might include: ‘Which seeds do you think will grow first?’, ‘Who do you think can jump the furthest?’ or ‘What will happen to the shadow in two hours’ time?’. This kind of questioning will inspire students to find answers.
  4. Conduct an experiment: Student-driven investigations, based on questions that students have generated themselves will be more motivating and meaningful to them. You can provide students with simple equipment to create their own investigations. Your students can provide oral feedback about what they have noticed or can draw and label what they have observed.
  5. Collect results: Recording and collecting data is fundamental to the scientific method, with data students would not be able to draw conclusions about the way the world works around them. Data can be collected and represented in a variety of ways such as, graphs, tables, sketches, photos, videos and journals.
  6. Conclusion: It is preferable for students to draw their own conclusions rather than be provided with answers by their teacher. You can help your students to construct their own meaning by asking them carefully worded open-ended questions. Examples might include: ‘Why do you think the coin sinks and the straw floats?’ or ‘Why does your heart beat quickly when you jump for one minute?’. Allowing students to develop their own ideas can lead to further questions and investigations!
  7. Communicate the results: Students should be given opportunities to discuss what they have noticed with their teachers and peers. This will help them to make connections between cause and effect, and help to organise their thinking.

You may have noted down similar ideas in response to the ‘Pause for thought’ questions in Section 1.

3 Putting the scientific method into practice

The following activity invites you to consider how students’ scientific skills are developed through completing an investigation.

Activity 1: Video: investigating germination

Watch the video below, which shows how a teacher supports her students to investigate germination. If you are unable to watch the video, it shows the teacher skilfully using the scientific method to organise the investigation, while still allowing her students to lead it and make any associated decisions, such as which variable to change. She provides a simple chart for her students to record their data and allows her students to choose their preferred method to do so. Some students draw pictures while others combine words and pictures. The students are given the opportunity to observe the work of their classmates, which helps them to develop their own conclusions. At the end of the lesson, the teacher asks her students to report their findings. You may also find it useful to read the video transcript.

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Watch the video again and answer the following questions:

  • How did the teacher allow her students to guide the classroom investigation on germination?
  • How was the scientific method used during the investigation?
  • Were her students aware that they were following the scientific method?
  • What scientific skills did the students develop during the investigation?
  • What impact did the investigation have on the students’ attainment?

Pause for thought

What did you like about the lesson in the video? How could you apply these ideas to your classroom practice?

Case Study 1: Mrs Yadav’s students use the scientific method

Mrs Yadav, an elementary science teacher, wanted to inspire her students to generate questions, produce a hypothesis and draw conclusions about the germination of seeds. To do this, she decided to read out a letter to her students, pretending that it had been written by a local farmer called Mr Desai.

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As soon as I had read out the letter to them, my students assured me they knew which farmer it must be! They were most concerned about his situation and very keen to help him.

First, I asked them to recall what they had been told were the essential requirements for the successful germination of plants. I wrote up their contributions on the board:

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I then asked my students. ‘How can we be sure this information is right? What will happen if we send the wrong information to Mr Desai and his seeds don’t grow properly?’

One of my students suggested that we could buy some seeds and try to grow them under different conditions to ensure that Mr Desai received the correct information. So the following day I brought some seeds, small pots and soil into school.

I arranged my students into groups of eight and asked them to think about what they wanted to find out and how this would help Mr Desai. I asked them to write down any questions they had about seeds. I walked around the class and listened to them discussing their ideas. I stopped the class and asked them to share their questions. One group asked the question ‘Can seeds die if you give them too much water?’ Another group asked ‘If a seed is too cold, will it die?’

Using the board, I demonstrated how to turn a question into a statement. These statements could be considered hypotheses (scientific predictions).

Two examples, based on the questions above were:

  • Seeds die if you give them too much water.
  • If a seed is too cold, it will die.

Each group of students wrote a hypothesis (scientific prediction) in their exercise books. The students then planted their seeds and decided where to put them. This is what my students decided to do with their seeds:

  • one group gave their seed water, soil, light, warmth and attention
  • one group of students didn’t water their seed
  • one group put their seed in a dark place
  • one group put their seed in the staff refrigerator
  • one group decided to soak their seed in water.

I gave my students a simple table to record their observations. I asked them to look after their seeds and record their observations every two days over a period of two weeks. Some students drew pictures to record their observations; others added labels and captions. All checked for growth and measured it with a ruler. On the last day, I brought in a camera and allowed my students to take photographs of their experiments.

I asked each group to write a letter back to Mr Desai, explaining what they had done with their seed, what evidence they had collected and what this told them about seed growth. Here is a letter one group of students wrote to Mr Desai:

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I was nervous about letting my students lead the investigation and decide what to do with their seed. I wasn’t sure if their ideas would be relevant to the task. However, I need not have worried. Providing them with an initial problem to solve helped to focus their ideas and discussions. I was very pleased with the way they generated their own questions. Most students needed a little support to change their question into a hypothesis (scientific prediction) and some also needed help with writing a clear conclusion. However, the activity was very absorbing and proved a great success. I am sure Mr Desai’s seeds will grow successfully this year!

The next activity asks you to reflect on Mrs Yadav’s lesson.

Activity 2: Reflecting on Mrs Yadav’s lesson

What made Mrs Yadav’s lesson a success? Would you use any of her ideas in your own teaching?

Write the following headings:

  • Question/problem
  • Observation/research
  • Form a hypothesis
  • Conduct an experiment
  • Collect results
  • Conclusion
  • Communicate the results

Under each heading, note down how Mrs Yadav managed each stage of the scientific method.

4 Planning and assessing an investigation with your students

This activity asks you to plan an investigation on germination with your class.

Activity 3: Planning an investigation with your students

Choose one activity from the list below and, using the lesson plan template  introduced in TDU 1, Using brainstorming to elicit prior knowledge: sound and musical instruments, create a detailed lesson plan that will support your students through the stages of the scientific method. Remember that the scientific method does not have to be followed rigidly.

  • How does gravity affect the way a seed grows?

    Setting the scene: Indian astronauts are planning the first manned mission to Mars. It will take two years to complete their mission. The astronauts will need to grow their own food, but their spacecraft is very small. The only place to grow seeds will be on the ceiling of their space craft. The space centre needs to know if seeds can grow upside down.

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  • What is the effect of fire on seed germination?

    Setting the scene: A fire has destroyed a farmer’s storage shed. Some of the seeds that he was storing to plant later in the year have been burnt. He needs to know if the seeds will still germinate and if the plants will grow normally. (It is advisable that an adult burns some seeds for the students to use in this activity.)

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  • How does soil salinity impact on seed germination?

    Setting the scene: A young girl who lives near Vishakhapatnam wants to grow some plants for a school gardening competition. There has not been much rain in the past few months and water is short. She needs to know if she can water her plants with sea water instead.

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Use Figures 1 or 2 at the beginning of this unit to help you identify what you and your students will need to do during the investigation. Your students may need you to use open-ended questions to support them through the investigation.

Consider the equipment that you will need. Recycled bottles and food containers can be used to plant pots and soil can be dug up from an outside area – although you will need to make sure that it is free of other plant material as far as possible.

Resource 3 can be adapted to support your students with any kind of classroom investigation.

Pause for thought

After planning and delivering your lesson, make brief notes to answer the following questions.

  • What went well during the investigation?
  • In what way did your students follow the scientific method?
  • What assessment opportunities did the activity present?
  • Did the investigation change your students’ ideas and thinking?
  • If you had the chance to teach this lesson again, would you do anything differently? What? Why?

Continuous and comprehensive evaluation (CCE)

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Assessing students' scientific investigation skills can be challenging, especially when it involves large classes. Some of these skills can be assessed by evaluating student outputs, such as their data collection, conclusions, reports or verbal presentations. However, in the absence of such outputs, progression can be difficult to assess.

Students’ practical skills are best assessed as they are engaged in the investigation itself. With large classes, it is more effective to observe one or two groups of students in turn over several lessons. Your notes can be made about a group of students as a whole or the individual students within it. Your observations can be quite general or can focus on particular skills such as asking questions, selecting appropriate equipment or drawing conclusions.

The assessment grid in the next section may be helpful when observing students as they undertake practical tasks. The grid can be copied and used for a group of students or each individual within it.

If you don’t have access to a photocopier, you can ask your students to copy out the statements that apply to them. This will make them aware of the skills you are looking for during an investigation.

The following activity asks you to assess a younger student’s scientific skills, based on written evidence.

Activity 4: Assessing scientific investigation

Task 1

Print out a copy of Resource 4, or copy it into your notebook. Use a coloured pen to highlight the skills that you observe over the duration of an investigation. Some students, or groups of students, will demonstrate skills from two levels. However, you should just highlight one of these – the one that best fits the students you are observing. A different coloured pen can be used for future observations. This will help you to identify the progression that your students have made.

Task 2

A student from Class I completed an investigation on seed germination. She set up a practical investigation with the support of her teacher and recorded her findings ten days later (Figure 3).

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Figure 3 A student’s investigation on seed germination

Look again at Resource 4. Which level best describes this student’s ability and why? What factors cannot be assessed by looking at the written evidence?

Now ask a colleague to complete the same task. Do you both agree about the level of the student’s work? What do you disagree about?

5 Summary

Elementary students will only develop their scientific investigation skills by ‘doing’ science. Teachers need to provide opportunities for students of all ages to carry out open-ended investigations that are meaningful and relate to their life experiences. It is only through practical investigation that students will develop essential thinking skills that will enable them to distinguish between scientific claims and facts.

This unit has explored how young students can use the scientific method to develop their skills of scientific investigation with the support of their teachers. With appropriate teacher support, elementary level students are capable of asking questions, making observations, predicting outcomes, carrying out practical investigations, recording information, interpreting data, drawing conclusions and reporting findings. Incorporating investigations into their learning will increase students’ enjoyment of science, improve their skills, and contribute to the development of complex critical thinking for the future.

6 Resources

Resource 1: A closer look at the scientific method

  1. Question/problem: Questions drive the scientific method. The students’ questions should arise from observing the natural world. Those that begin with ‘Why?’, ‘What?’, ‘How?’ and ‘When?’ will help to focus an investigation and develop a prediction or hypothesis. A sample question would be: ‘How does lack of water affect plant growth?’
  2. Observation/research: ‘Research’ means finding out more about the chosen topic. Ideally, this should involve a combination of making closer observations and consulting other sources of information (such as textbooks or the internet). Undertaking this kind of research can help to refine the students’ initial question.
  3. Form a hypothesis: The next step is to turn the initial question into a hypothesis. A hypothesis is a clear statement that indicates what the investigator predicts that the answer to the question might be. For example: ‘Lack of water will reduce plant growth’. Other terms for a hypothesis are an ‘educated guess’ or a ‘scientific prediction’. A hypothesis must be testable.

    Students should be encouraged to make predictions about the possible outcomes of their investigations. For example: ‘if I reduce the amount of water a plant has, then the plant will stop growing.’

  4. Conduct an experiment: A hypothesis should be tested by conducting a controlled experiment where only one factor is changed at a time. An experiment should have a control group and one or more experimental groups. For example, a plant that is watered regularly would be the control group, whereas the plant that is not watered would be the experimental group. All factors between the control and the experimental groups must be the same, except for one factor, which is called the variable. In this experiment, the seed type, the amount of soil in the plant pot and the level of exposure to light must all remain the same. The only factor that should be different is the amount of water that each plant is given. The results will thus be the consequence of the one change that has been made.

    An independent variable is the part of the experiment that will be tested (varied) to answer the hypothesis. In the example above, the independent variable would be the amount of water a plant is given. A dependent variable is what occurs in response to the changing independent variable. In the example above, the dependent variable is how much the plant grows.

  5. Collect results: Recording the results during an experiment is a fundamental part of the scientific method, because it helps to organise ideas and observations. Results can be recorded using graphs, lists, diagrams, sketches, photographs or even video recordings.
  6. Conclusion: After completing the experiment and recording all the results, the next step is to consider what conclusions can be drawn from the investigation. A conclusion should be made as to whether or not the findings support or reject the hypothesis. If the hypothesis has been supported, the experiment can be done again to confirm the results. However, if the hypothesis has not been supported, the experimental procedure may need to be checked. If a conclusion cannot be drawn from the results, this may present a new question that can then be tested in another experiment.
  7. Communicate the results: After the completion of an investigation, the results can be reported. A report can consist of a written or oral account of what was learned and concluded from the experiment.

Resource 2: What is a fair test?

It is important for an experiment to be a fair test. You conduct a fair test by making sure that you change one factor (variable) at a time, while keeping all other conditions the same.

For example, imagine your students are testing two toy cars to see which one is the fastest by releasing them from the top of a sloping ramp. If one car is pushed and the other released gently, then the test is not fair, because one of the cars has an advantage over the other.

If your students are struggling with the concept of what makes a fair test, you could describe a simple test and ask them if it is fair or not. You could make a fair test quiz or card game.

Resource 3: Investigation sheet

This investigation sheet can be used to help your students’ understanding of the scientific method. The sheet can be adapted to suit your lesson or the learning needs of your pupils. It can be copied and enlarged and used as a classroom poster to remind students of the scientific method.

Resource 4: Assessing a scientific investigation

Level 1

Students can:

  • suggest how to find things out and, with help, make suggestions about collecting data that will answer questions
  • make simple predictions
  • use simple texts, with help, to find information
  • use simple equipment and make observations during an investigation
  • observe and compare objects, living things and events
  • describe observations using scientific vocabulary and record them, using simple tables
  • say whether what happened was what they expected.

Level 2

Students can:

  • suggest how to find things out and put forward ideas about how to find the answer to a question
  • understand why it is important to collect data to answer questions
  • make and justify predictions
  • use simple texts to find information
  • make relevant observations and measure quantities, using a range of simple equipment
  • carry out a fair test with some help, understanding and explaining why it is fair
  • record observations in different ways
  • explain observations and simple patterns in recorded measurements
  • show in a scientific way what has been found out and suggest improvements to work.

Level 3

Students can:

  • recognise that scientific ideas are based on evidence
  • find the best way to answer a question in investigative work
  • know how to change one factor or variable while keeping others the same in an experiment
  • make predictions based on scientific knowledge and select information from sources
  • choose suitable equipment and make observations and measurements in an experiment
  • record observations, comparisons and measurements using tables and bar charts, and plot results on simple graphs
  • use graphs to find and interpret patterns in data
  • relate conclusions to patterns found in data as well as scientific knowledge and understanding
  • share findings using appropriate scientific language and suggest improvements to work, giving reasons why.

7 Related units

All 15 Elementary Science teacher development units aim to explore investigative skills. The principles in this unit can therefore be applied to the activities and practical tasks suggested in all of them.

References

Ask (undated) ‘What are three different ways you could record or summarize data in your science journal?’ (online). Available from: http://www.ask.com/ question/ what-are-three-different-ways-you-could-record-or-summarize-data-in-your-science-journal (accessed 13 December 2013).
BrainPOP (undated) ‘Lesson ideas: scientific method’ (online), BrainPOP Educators. Available from: http://www.brainpopjr.com/ science/ scienceskills/ scientificmethod/ grownups.weml (accessed 13 December 2013).
Dalcour, J. (undated) ‘How to record & analyse data using the scientific method’ (online), eHow. Available from: http://www.ehow.com/ how_8681934_record-data-using-scientific-method.html (accessed 13 December 2013).
Julian’s Science Fair (undated) ‘Seeds & germination’ (online). Available from: http://www.juliantrubin.com/ fairprojects/ botany/ seedsgermination.html (accessed 13 December 2013).
My Science Journal (2008) ‘Germination investigation’ (online). Available from: http://mysciencejournal.pbworks.com/ w/ page/ 11341701/ Germination%20Investigation (accessed 13 December 2013).
New Mexico State University (undated) ‘Measuring germination rates’ (online). Available from: http://ddl.nmsu.edu/ kids/ explore/ experiments/ germination.html (accessed 13 December 2013).
Rillero, P. (1999) ‘Raphanus sativus, germination, and inquiry: a learning cycle approach for novice experimenters’ (online), University of Nevada, Reno. Available from: http://wolfweb.unr.edu/ homepage/ crowther/ ejse/ rillero.html (accessed 13 December 2013).
Science Stuff (undated) ‘The scientific method’ (online). Available from: http://sciencefairproject.virtualave.net/ scientific_method.htm (accessed 13 December 2013).
ThinkQuest (undated) ‘Germination’ (online). Available from: http://library.thinkquest.org/ C0118022/ germnation.htm (accessed 13 December 2013).
Wisconsin Fast Plants (undated) ‘Growth, development and reproduction’ (online). Available from: http://www.fastplants.org/ pdf/ activities/ WFP_growth-development-06web.pdf (accessed 13 December 2013).
The Worlds of David Darling (undated) ‘Germination’ (online), Encyclopedia of Science. Available from: http://www.daviddarling.info/ encyclopedia/ G/ germination.html (accessed 13 December 2013).

Acknowledgements

The content of this teacher development unit was developed collaboratively and incrementally by the following educators and academics from India and The Open University (UK) who discussed various drafts, including the feedback from Indian and UK critical readers: Jane Devereux, Kavita Grover and Christine James.

Except for third party materials and otherwise stated, this content is made available under a Creative Commons Attribution-ShareAlike licence: http://creativecommons.org/licenses/by-sa/3.0/.

The material acknowledged below is Proprietary and used under licence (not subject to Creative Commons Licence). Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit:

Grateful acknowledgement is made to the following:

Video: appreciation and thanks are extended to the participation of teachers and students at Ramjas School, R.K. Puram and all those involved in the making of this video.

Images:

Case Study 1: Photo of seed - by Jane Devereux for The Open University

CCE Logo: www.cbse.nic.in

Figure 3: example of student’s work © unidentified student

Every effort has been made to contact copyright owners. If any have been inadvertently overlooked, the publishers will be pleased to make the necessary arrangements at the first opportunity.