Topical questions: The Scientific Endeavour

State the SI unit of each quantity, and name an instrument used to measure it in the school lab.

1. (a)Time[1]
2. (b)Mass[1]
3. (c)Volume of a liquid[1]

A bottle carries a hazard symbol showing a skull and crossbones. State what the symbol means and give two precautions for using the substance.

Describe how to read the volume of water in a measuring cylinder accurately.

State two differences between the luminous flame and the non-luminous flame of a Bunsen burner.

Name the piece of apparatus used for each job.

1. (a)Holding a test tube while it is heated[1]
2. (b)Supporting a beaker above a Bunsen burner[1]
3. (c)Adding a liquid a few drops at a time[1]

Some Sec 1 students want to find out how the temperature of water affects the time taken for a vitamin C tablet to dissolve.

1. (a)Identify the independent variable.[1]
2. (b)Identify the dependent variable.[1]
3. (c)State two variables that must be kept the same.[2]

During a practical lesson, a Bunsen burner suddenly makes a roaring sound. The flame disappears from the top of the barrel and a small flame burns at the bottom. The barrel becomes very hot.

1. (a)Name what has happened.[1]
2. (b)Suggest one cause.[1]
3. (c)Describe three things the student should do.[3]

An irregular stone is lowered into a measuring cylinder containing 35.0 cm³ of water. The water level rises to 48.5 cm³.

1. (a)Calculate the volume of the stone.[2]
2. (b)State one assumption made when using this method.[1]

A student needs 18 cm³ of water. She can use a 25 cm³ measuring cylinder marked every 0.5 cm³, or a 100 cm³ measuring cylinder marked every 1 cm³.

1. (a)Which measuring cylinder should she use?[1]
2. (b)Explain your choice.[1]
3. (c)State two things she should do to read the volume accurately.[2]

A student wants to find the thickness of one page of her textbook using a 30 cm ruler marked in millimetres.

1. (a)Explain why she cannot measure the thickness of one page directly.[1]
2. (b)Describe a better method.[1]
3. (c)200 pages pressed together are 1.6 cm thick. Calculate the thickness of one page in mm.[2]

A student times a pendulum with a stopwatch. Explain why she should time 20 complete swings and divide by 20, instead of timing one swing.

A student says: “The yellow luminous flame is brighter than the blue flame, so it must be hotter.” Evaluate this statement.

A student investigated how the temperature of water affects the time taken for 2 g of sugar to dissolve. Her results are shown in the table.

1. (a)Identify the anomalous result.[1]
2. (b)Suggest what the student should do about it.[1]
3. (c)Describe the pattern shown by the other results.[1]
4. (d)Which variable should be plotted on the x-axis of a graph?[1]
5. (e)State one variable she should keep the same.[1]

Two students each need 40 cm³ of water. Student A uses a 250 cm³ beaker marked every 50 cm³. Student B uses a 50 cm³ measuring cylinder marked every 1 cm³. Explain which student measures the volume more accurately.

A scientist finds that 2 out of 10 trials give unexpected results. Describe how she should show the scientific attitudes of integrity and objectivity when she reports her findings.