Exercises: Extended Experimental Investigation (CBA 1)

The Extended Experimental Investigation (EEI) is the first Classroom-Based Assessment (CBA) in Junior Cycle Science. Answer using what you know from the Junior Cycle Science specification.

1. a) State when in junior cycle the EEI is completed.

1. b) State over how long a period students work on the EEI.

1. c) List the four main things the specification says students do during the EEI. Use the action verbs from the specification (for example "formulate").

1. d) Name two of the formats in which the EEI report may be presented.

1. e) State who supports and guides the student during the EEI.

1. f) The EEI uses primary data. Explain in one sentence what primary data are, and give one example of data that would not be primary data.

Aoife, a 2nd year student in Tralee, wants to investigate how fast sugar dissolves. She writes three statements in her notebook:

• Statement 1: "Does the temperature of the water change how fast a sugar cube dissolves?"

• Statement 2: "Sugar is lovely in tea."

• Statement 3: "If the temperature of the water is increased, then the time taken for a sugar cube to dissolve will decrease."

1. a) Decide which statement is a scientific question, which is a hypothesis, and which is neither. Give a short reason for each.

1. b) Formulate a hypothesis, written in the form "If ... then ...", for this question: Does the amount of light affect the number of bubbles released by a piece of pondweed in one minute?

1. c) Explain why a hypothesis for an EEI must be something you can test by measuring.

Seán, in a school in Ennis, investigates whether the length of a pendulum affects how long it takes to complete 10 swings. He uses string lengths of 20 cm, 40 cm, 60 cm, 80 cm and 100 cm. He uses the same 50 g bob each time, releases it from the same small angle, and times it with the same stopwatch.

1. a) Identify the independent variable and give its unit.

1. b) Identify the dependent variable and give its unit.

1. c) List three variables Seán keeps constant (controlled variables).

1. d) Name the instrument used to measure the independent variable and the instrument used to measure the dependent variable.

1. e) Explain why Seán times 10 swings and not just one swing.

Niamh, a 2nd year student in Cork, plans to investigate how the temperature of water affects the time an effervescent vitamin tablet takes to dissolve completely in $150\ \text{mL}$ of water. Her teacher will pour the hot water from a kettle. She has beakers, a thermometer, a stopwatch, a measuring cylinder and safety goggles.

1. a) Identify the independent variable, the dependent variable and three variables she must control.

1. b) Copy and complete a risk assessment table with the columns Hazard, Possible harm and Control measure. Include at least two different hazards. "Be careful" is not an acceptable control measure; each one must say exactly what you do.

1. c) Write a numbered method of at least six steps. It must include: five different temperatures, how the temperature is checked, how the time is measured, and how many times each temperature is repeated.

1. d) The specification says the teacher supports and guides students during the EEI. State one point in Niamh's plan where she should check with her teacher before going ahead, and explain why.

Niamh carried out her investigation and recorded the time for the tablet to dissolve completely:

Temperature ($^\circ$C)	Trial 1 (s)	Trial 2 (s)	Trial 3 (s)
10	92	88	90
20	64	61	66
30	45	70	43
40	31	33	30
50	22	21	23

1. a) Identify the result that looks anomalous. Suggest one likely cause of it.

1. b) Decide whether to include or exclude the anomalous result when calculating the mean for that temperature. Justify your decision.

1. c) Calculate the mean time for each temperature. Show your working for at least one row.

1. d) Present your means in a neat results table with correct headings and units.

1. e) Describe how you would draw a graph of the means: which variable goes on which axis, what the axis labels are, how you would choose the scale, and what kind of line you would draw through the points.

1. f) Describe the pattern in the means in one sentence that includes at least two numbers from your table.

Niamh's hypothesis was: If the temperature of the water increases, then the time for the tablet to dissolve will decrease. Her first draft of a conclusion was:

"My hypothesis was proved. Hot water is better. The tablet dissolved quicker in the hot water. Everything went well."

Use the results from the previous task (the means were about $90\ \text{s}$ at $10\ ^\circ\text{C}$ and $22\ \text{s}$ at $50\ ^\circ\text{C}$).

1. a) Rewrite the conclusion in 4-6 sentences. It must refer to the hypothesis, quote data with units, describe the pattern, give a scientific explanation based on the movement of particles, and avoid claiming more than the data show.

1. b) Explain why "my hypothesis was proved" is not a good way to put it.

1. c) Assess your rewritten conclusion with this rubric. For each criterion, give the level you think you reached and quote the words from your answer that show it.

Criterion 1: Link to the hypothesis

• Level 1: Does not mention the hypothesis.

• Level 2: Says whether the hypothesis was supported, but gives no data.

• Level 3: Says whether the hypothesis was supported and backs it with data.

Criterion 2: Use of data

• Level 1: No numbers, or numbers without units.

• Level 2: One number with units.

• Level 3: At least two numbers with units, describing a pattern.

Criterion 3: Scientific explanation

• Level 1: No explanation.

• Level 2: Explanation is vague ("it works better").

• Level 3: Explanation uses particle movement correctly.

Criterion 4: Scope of the claim

• Level 1: Claims go beyond the data (for example, "any temperature").

• Level 2: Some limit is stated, but not clearly.

• Level 3: Claim is limited to the range tested.

A group of students at a school in Galway investigate how the distance of a lamp from a piece of pondweed affects the number of bubbles it releases per minute. Their hypothesis was: The closer the lamp, the more bubbles are released. The pondweed stayed in the same beaker of water throughout. A normal filament lamp was used, one student counted the bubbles by eye, and the investigation was done in a room with a window.

Distance of lamp (cm)	Bubbles per minute, trial 1	trial 2	trial 3
10	48	52	50
20	31	29	33
30	18	20	19
40	12	11	13
50	8	9	7

1. a) Calculate the mean number of bubbles per minute for each distance.

1. b) Describe the pattern. Say whether the data support the hypothesis, and quote numbers to back up your answer. Also say whether doubling the distance from $10\ \text{cm}$ to $20\ \text{cm}$ halves the number of bubbles.

1. c) Evaluate the data by identifying at least three sources of error or limitations in the method (use the information in the description above). For each one, state how it could have affected the results and suggest one specific improvement.

1. d) Find the range (highest minus lowest) of the three trials at $10\ \text{cm}$ and at $20\ \text{cm}$. Explain what the ranges, and the fact that they do or do not overlap, tell you about how much confidence you can have in the conclusion.

1. e) Suggest one new investigation question that follows from these results.

Plan your own investigation. Choose one of these starting ideas:

• A: Does the colour of paper wrapped around a glass jar of water affect how much the temperature rises in 20 minutes on a sunny windowsill?

• B: Does the mass of bread soda (sodium hydrogencarbonate) added to a fixed volume of vinegar affect the volume of gas collected?

• C: Does the mass of a load on a small trolley affect the distance it rolls after leaving a ramp?

The investigation must generate primary data that you collect yourself. Write a one-page plan with these headings:

1. Question and hypothesis (with a scientific reason for your prediction)

2. Variables table (independent, dependent, at least three controlled)

3. Materials

4. Safety (specific hazards and control measures)

5. Numbered method (at least five values of the independent variable, repeats stated)

6. A blank results table (headings, units, space for repeats and the mean)

7. How you will analyse the data (mean, graph, how you will decide whether the hypothesis is supported)

8. One point where you will ask your teacher for guidance

Then assess your plan with this rubric. Give a level for each criterion and one sentence of evidence.

Criterion A: Hypothesis

• Level 1: A question or opinion, not testable.

• Level 2: Testable, but no reason is given.

• Level 3: Testable, with a prediction and a scientific reason.

Criterion B: Variables and control

• Level 1: Variables are missing or mixed up.

• Level 2: Independent and dependent variables are correct, but fewer than three are controlled.

• Level 3: All variables are correct, with at least three controlled and how they are kept constant.

Criterion C: Method

• Level 1: Steps are unclear or cannot be repeated by someone else.

• Level 2: Steps are clear, but there are fewer than five values or no repeats.

• Level 3: Steps are clear, with at least five values, repeats, and how each measurement is made.

Criterion D: Safety

• Level 1: No hazards identified, or only "be careful".

• Level 2: Hazards are identified, but the control measures are vague.

• Level 3: Specific hazards with specific control measures.

Criterion E: Data handling plan

• Level 1: No plan for the data.

• Level 2: Mentions a table or graph only.

• Level 3: Table, mean, graph and how the hypothesis will be judged.

Ciara, a 2nd year student in Sligo, investigated how the mass of bread soda added to a fixed volume of vinegar affects the volume of gas produced. She kept this log during her three weeks:

1. Week 1, Monday: I chose my question and wrote my hypothesis: more bread soda, more gas.

2. Week 1, Tuesday: I planned to measure the gas by the size of a balloon. My teacher asked how I would measure it accurately, so I changed to collecting the gas in an upturned measuring cylinder over water.

3. Week 1, Thursday: My first trials with the same mass gave $12\ \text{cm}^3$, $25\ \text{cm}^3$ and $9\ \text{cm}^3$. I realised I poured the vinegar at different speeds and put the bung on late.

4. Week 2: I fixed a pouring routine and inserted the bung within 2 seconds. I tested five masses, three repeats each.

5. Week 3, Monday: I calculated the means and drew a line graph. The volume levelled off above 4 g.

6. Week 3, Wednesday: I think the vinegar was used up above 4 g, so adding more bread soda made no more gas. I'd need to test this.

1. a) For each of the six log entries, name which part of the investigation it belongs to: formulate a hypothesis, plan, conduct, analyse data or reflect on the process. Some entries may belong to more than one.

1. b) Write a first-person reflection of about 120-150 words as if you were Ciara. It must say what went well, what went wrong, what you changed and why, what you would do differently, and what you learned.

1. c) The specification lists these formats for presenting an EEI: a hand-written or typed report, model building, a multimodal presentation, a podcast or a webpage. Choose one and explain in 2-3 sentences how Ciara could use it to show her hypothesis, her data and her reflection.

1. d) Details such as suggested length, the features of quality and how the teacher makes an "on-balance" judgement are not in the specification extract. State where students should look for these and what they should ask their teacher for early in the process.

1. e) Assess your reflection from part (b) with this rubric. Give a level for each criterion and quote evidence.

Criterion 1: Honesty about what went wrong

• Level 1: Says everything went well.

• Level 2: Mentions a problem, but not its cause.

• Level 3: Names a specific problem and explains its cause.

Criterion 2: Link between problem and change

• Level 1: No change is described.

• Level 2: A change is described, but not why.

• Level 3: A change is described and explained, with its effect on the results.

Criterion 3: Looking forward

• Level 1: Nothing about next steps.

• Level 2: A vague improvement ("be more careful").

• Level 3: A specific improvement or a new question to test.