IB MYP Integrated Sciences e-Assessment : Pressure Exam Style Practice Questions - New Syllabus
Question (10 marks)
A student wonders if his guitar strings act like spider silk. He knows that his steel guitar strings have different diameters. The student wants to know if there is a relationship between the diameter of the string and how much force he can hang from the (unwound) string until it breaks.
Question (2 marks)
State the independent variable and the dependent variable in this experiment.
▶️Answer/Explanation
Independent Variable: Diameter of the guitar string
Dependent Variable: Force needed to break the string
Explanation:
– The diameter of the string is what the student is changing (independent variable).
– The force required to break the string is what is being measured (dependent variable).
Question (18 marks)
You are provided with several sets of guitar strings, each with the following diameters:
| Diameter of string / mm |
|---|
| 0.28 |
| 0.33 |
| 0.46 |
| 0.71 |
| 0.97 |
| 1.22 |
The following equipment is also available:
- Ruler
- Clamp stand
- Sticky tape
- Thermometer
- Stop clock
- Slotted masses
- Hanger
- Safety glasses
- Foam mat
- Thread
- Strong glue
- 1N weights
Design a method to investigate how the force needed to break a guitar string is related to the string’s diameter. In your answer, you should:
- Identify two control variables
- Select additional equipment you will use
- Describe how you will set up the equipment
- Outline how you will collect sufficient data
- Outline how to make suitable measurements
- State how you will make sure your method is safe
▶️Answer/Explanation
Method:
1. Control Variables:
– Temperature of the environment (keep constant using a thermometer).
– Length of the string (keep constant using a ruler).
2. Equipment:
– Clamp stand, slotted masses, hanger, ruler, safety glasses, foam mat.
3. Setup:
– Secure the guitar string horizontally using the clamp stand.
– Attach the hanger to the end of the string and place slotted masses on it.
– Place the foam mat below the setup to catch falling masses.
4. Data Collection:
– Gradually add 1N weights to the hanger until the string breaks.
– Record the force (in newtons) required to break the string for each diameter.
– Repeat the experiment three times for each string diameter to ensure reliability.
5. Measurements:
– Measure the diameter of each string using a ruler or calipers.
– Record the force at which the string breaks.
6. Safety:
– Wear safety glasses to protect eyes from snapping strings.
– Use a foam mat to prevent damage from falling weights.
– Ensure the clamp stand is securely fixed to avoid accidents.
Question (2 marks)
The student has plotted the results on the graph below:
Graph: Breaking force (N) vs Diameter of string (mm)
Outline the relationship between breaking force and diameter of the string.
▶️Answer/Explanation
Relationship:
– As the diameter of the string increases, the breaking force also increases.
– This indicates that thicker strings can withstand more force before breaking.
– The relationship is likely linear, meaning that doubling the diameter of the string would approximately double the breaking force.