# Physics - annotated exemplars level 1 AS90935

## Carry out a practical physics investigation that leads to a linear mathematical relationship, with direction (1.1)

### Low Excellence

Commentary
Student response

Student 1 (PDF, 82KB)

For Excellence, the student needs to carry out a comprehensive practical physics investigation, with direction, that leads to a linear mathematical relationship.

This involves writing a discussion that validates the conclusion. Each discussion point could relate to one of the bullet points listed in Explanatory Note (EN) 7.

The student has shown a link between the investigation findings and physics ideas (1) and has attempted to describe the link between the gradient of the graph and the spring constant of the spring (2). The student has attempted to justify the control of the spring (3), and has attempted to account for an unexpected outcome of the processing of the results (4).

For a more secure Excellence, the student could have:

• recognised that the spring constant can be calculated from the gradient only if the gradient is expressed in SI units
• considered what happened during the experiment to cause the unexpected outcome
• described the effect of the unexpected outcome on the validity of the conclusion.

### High Merit

Commentary
Student response

Student 2 (PDF, 88KB)

For Merit the student needs to carry out an in-depth practical physics investigation, with direction, that leads to a linear mathematical relationship.

This involves controlling significant variables, using appropriate accuracy improving techniques, drawing a valid linear graph and stating the equation of the relationship. Refer to Explanatory Note (EN) 6.

The student has controlled the significant variable by using the same spring (1), improved accuracy by repeating and averaging the measurements (2), drawn an appropriate linear graph (3) and stated the equation of the relationship in terms of the variables being investigated (4). The student has also explained the need to control a significant variable (7).

To reach Excellence, the student would need to write a discussion that validates the conclusion. Each discussion point could relate to one of the bullet points listed in EN7. The student could have:

• described how a method to improve accuracy had been particular to this measurement rather than just making a general statement (5)
• explained why the choice of limits to the range of independent variables was chosen in terms of gathering accurate data (6)
• linked the increased gravitational force on the mass to an increased force on the spring causing an increase in spring length (8)
• related the difficulty that has been described to an issue that could not be remedied by using appropriate experimental technique (9).

### Low Merit

Commentary
Student response

Student 3 (PDF, 82KB)

For Merit the student needs to carry out an in-depth practical physics investigation, with direction, that leads to a linear mathematical relationship.

This involves controlling significant variables, using appropriate accuracy improving techniques, drawing a valid linear graph and stating the equation of the relationship. Refer to Explanatory Note (EN) 6.

The student has attempted to identify significant variables as needing to be controlled (1). The accuracy of measurements has been increased by repeating and averaging (2), and a valid linear graph has been drawn (3).

Although the equation of the relationship has been written in terms of x and y rather than the variable names (4), since x and y have both been clearly defined the equation is sufficient (5).

For a more secure Merit, the student could have indicated that the variables other than the spring that have been listed as needing control are not significant variables. The student could have also drawn a graph line that had a better fit to the plotted points.

### High Achieved

Commentary
Student response

Student 4 (PDF, 86KB)

For Achieved the student needs to carry out a practical physics investigation, with direction, that leads to a linear mathematical relationship.

This involves developing a method, collecting data with units, drawing an appropriate graph and identifying the trend. Refer to Explanatory Note (EN) 5.

The student has listed the correct experimental procedures (1) and has collected reasonable measurements for the extended lengths of the spring (2). A linear graph based on the data, with correctly constructed axes, has been drawn (3). The trend has been correctly identified by the student (4).

The student has increased the accuracy of measurements by repeating and averaging the measured lengths (6). The equation of the relationship has been written in terms of the variable names and an attempt has been made to include the gradient of the graph in the relationship (7).

To reach Merit the student would need to carry out an in-depth practical physics investigation, with direction, that leads to a linear mathematical relationship. Refer to EN6.

The student would also need to:

• identify the variables that could have had a significant effect on the results and describe how to control these (5)
• correctly calculate the value of the gradient used in the relationship equation (7).

### Low Achieved

Commentary
Student response

Student 5 (PDF, 81KB)

For Achieved the student needs to carry out a practical physics investigation, with direction, that leads to a linear mathematical relationship.

This involves developing a method, collecting data with units, drawing an appropriate graph and identifying the trend. Refer to Explanatory Note (EN) 5.

The student has listed appropriate experimental procedures (1) and has collected reasonable measurements for the extended lengths of the spring (2). An appropriate graph has been drawn, and an attempt has been made to plot points accurately (3). The student has made several attempts to show they have recognised that the required trend is that increased mass causes an increased spring length (4).

For a more secure Achieved, the student could have plotted all points on the graph correctly. The student could also have written a conclusion that clearly links the processed data to the identified trend on the graph.

### High Not Achieved

Commentary
Student response

Student 6 (PDF, 81KB)

For Achieved, the student needs to carry out a practical physics investigation, with direction, that leads to a linear mathematical relationship.

This involves developing a method, collecting data with units, drawing an appropriate graph and identifying the trend. Refer to Explanatory Note (EN) 5.

There is sufficient evidence that a suitable method has been developed (1). An attempt has been made to measure spring lengths for different masses (2). A linear graph with correctly plotted points has been drawn, and an attempt has been made to draw a line to show the trend (3). An attempt has been made to identify the trend (4).

To reach Achieved, the student would need to measure values of the stretched spring length accurately. The line of best fit in the graph would need to be drawn to represent data appropriately, rather than just joining the first and last plotted points. The trend statement would need to state that the length of the spring increased as the mass increased.