❌ 9. Required Practical: Stretch Tests (P10)

Question 1

What is an Independant Variable

Answer 1

In Independant Variable is the variable that is altered during a scientific experiment.

Question 2

What is a Dependant Variable

Answer 2

A Dependant Varibale is the variable being tested or measured during a scientific experiment.

Question 3

What is a Control Variable

Answer 3

A Control Variable is the variable that is kept the same during a scientific experiment.

Question 4

Stretch Tests RP: Safety

Answer 4

• Eye protection must be worn.
• The clamp stand should be securely fastened to the bench.
• Do not make the masses bounce up and down on the spring.
• Make sure masses do not fall onto the floor or onto people’s feet.

Question 5

Stretch Tests RP: Equipment and Materials

Answer 5

• Eye Protection
• Spring
• Set Of 50 g (0.5 N) Masses
• Mass Holder
• 1 meter ruler
• Clamp stand with three clamps
• G-clamp

Question 6

Stretch Tests RP: Method

Answer 6

1. Attach the spring to the clamp stand by hanging it off a clamp, and allow the spring to hang freely over the side of the bench.
2. Use the G-clamp to fasten the clamp stand to the bench.
3. Use the other two clamps to hold the ruler vertically, close to but not touching
   the spring. You will use this to measure the length of the spring.
4. Measure the length of the spring with no force acting on it.
5. Hang the mass holder from the spring. Check the mass of the holder, and measure the new length of the spring. Record the length of the spring and the mass suspended from it.
6. Add a 50 g (0.5 N) mass and measure the length of the spring.
7. Repeat step 6 until a total of 250 g (including the mass holder) is hanging from the spring. Each time, record the length of the spring and the total mass suspended from the spring.
8. Remove a 50 g mass.
9. Measure the length of the spring.
10. Repeat steps 8 and 9 until there is no mass hanging from the spring.
11. Record all your results in a table.

Question 7

What to put the Results Table

Answer 7

The Results Tabke should have 6 columns with:

• Weight in N
• Stretched Length in cm: When adding masses
• Stretched Length in cm: When removing masses
• Stretched Length in cm: Mean
• Original Length in cm
• Average Extension (Average Stretched Length - Original Length) in cm.

Question 8

What to put on the Graph

Answer 8

On the graph, the X-Axis has the Force (N) on it, and the Y-Axis has the Extension (cm) on it.

From here, there should be a positive correlation between the increase of Force and Extension, and the line of best fit should be linear, while travelling in this positive correlation.

(See Goodnotes for more Information)

Question 9

How do you find out the Spring Constant

Answer 9

To find tne Spring Constant, you will essentially need to draw a triangle on the graph, connecting two points. You will need to know the length and height of this triangle.

Now you will need to do:

The length of the triangle / The height of the Triangle = Spring Constant

Force (N) / Extension (cm) = Spring Constant (N/cm)

Question 10

What is the independent variable in this experiment?

Answer 10

The independant variable is the Force (N)

Question 11

What is the dependent variable in this experiment?

Answer 11

The dependant variable is the length of Extension (cm).