You will find the volume of a small glass ball (marble) by two different methods. You are provided with: • six similar small glass balls (marbles) • a metre rule fixed in place on the bench • two set squares • a 50 cm³ measuring cylinder • a 100 cm³ beaker containing water • access to a top-pan (electronic) balance • paper towels.

1. (a)method 1 • Place six small glass balls by the side of the metre rule, as shown in Fig. 1.1. • Make sure that there are no gaps between the balls. [Figure 1.1]
2. (a)(i)Use the set squares to help you take readings on the metre rule of the positions of points A and B, as shown in Fig. 1.1. Give your readings to the nearest 0.1 cm. position of point A = .................................................... cm position of point B = .................................................... cm[1]
3. (a)(ii)The length l is the distance between points A and B. The average diameter d of one ball can be found using the equation: l = 6d Use your answers to (a)(i) to find length l and diameter d. Give your answers to the nearest 0.1 cm. l = .................................................... cm d = .................................................... cm[2]
4. (a)(iii)The average volume V of one glass ball found using this method is given by the equation: V = 3.14d³/6 Calculate V. V = .................................................... cm³[1]
5. (b)method 2 • Pour water into the measuring cylinder until it is just over half full.
6. (b)(i)Record the volume V₁ of the water in the measuring cylinder. V₁ = .................................................... cm³[1]
7. (b)(ii)• Carefully add the six glass balls to the water in the measuring cylinder. Record the new volume V₂ of the water and glass balls in the measuring cylinder. V₂ = .................................................... cm³ The volume V_T of the six balls is given by the equation: V_T = V₂ – V₁ Calculate V_T. V_T = .................................................... cm³[1]
8. (b)(iii)• Remove the glass balls from the measuring cylinder and dry them using the paper towel. Calculate the average volume V of one ball found using this method. V = .................................................... cm³[1]
9. (c)Suggest whether method 1 or method 2 gives the more accurate value for the volume of the ball. Explain your answer. method giving more accurate value ............................................................................................ explanation ................................................................................................................................[1]
10. (d)The average mass of a glass ball can be found using a small beaker and a top-pan balance. Find the average mass of one glass ball using the small beaker and the top-pan balance supplied. Describe your method and record the readings you take. method ..................................................................................................................................... ................................................................................................................................................... readings .................................................................................................................................... mass of one glass ball = .................................................... g[2]

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