Science Year 3 PdPR Week 22 Wednesday 7th July 2021 - UNIT 6 ... - Free Printable

Problem Analysis:

The worksheet is about measuring the volume of liquids. It consists of two main tasks:

1. Identifying apparatus that can be used to measure the volume of liquids.
2. Determining the correct eye position to read a measuring cylinder and explaining the reasoning.

Let's solve each part step by step.

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Task 1: Tick the apparatus that can be used to measure the volume of liquids.

#### Apparatus shown:
1. Syringe
2. Tape measure
3. Balance scale
4. Ruler
5. Graduated cylinder
6. Beaker

#### Explanation:
- Syringe: Can measure small volumes of liquid accurately, especially in laboratory settings.
- Tape measure: Used for measuring length or distance, not suitable for measuring liquid volume.
- Balance scale: Used for measuring mass, not volume.
- Ruler: Used for measuring length, not volume.
- Graduated cylinder: Specifically designed to measure liquid volume with precise markings.
- Beaker: Can hold liquids but does not have precise markings for accurate volume measurement; it is generally used for rough estimates.

#### Correct choices:
- Syringe (✓)
- Graduated cylinder (✓)

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Task 2: Join the dotted lines to show the correct eye position to read the measuring cylinder.

#### Part (i): Join the dotted lines.
The image shows a measuring cylinder with liquid up to the 40 mL mark. There are three eye positions indicated:
1. Above the meniscus (top view).
2. At the level of the meniscus (correct view).
3. Below the meniscus (bottom view).

The correct eye position is at the level of the meniscus (the bottom curve of the liquid surface). This ensures an accurate reading without parallax error.

#### Part (ii): Explain your answer.
The explanation for the correct eye position is as follows:

- The meniscus is the curved surface of the liquid in the measuring cylinder. For water and most liquids, the meniscus forms a concave curve.
- To read the volume accurately, the eye must be at the same horizontal level as the bottom of the meniscus. This eliminates parallax error, which occurs when the eye is not aligned properly and leads to incorrect readings.
- If the eye is above or below the meniscus, the reading will be inaccurate due to the curvature of the liquid surface.

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Final Answer:

1. Apparatus that can measure the volume of liquids:
- Syringe (✓)
- Graduated cylinder (✓)

2. Correct eye position to read the measuring cylinder:
- Join the dotted line from the eye to the level of the meniscus (at the 40 mL mark).
- Explanation: The eye should be at the same horizontal level as the bottom of the meniscus to avoid parallax error and ensure an accurate reading.

Boxed Final Answer:
\[
\boxed{\text{Syringe, Graduated cylinder; Eye at the level of the meniscus}}
\]