S1 27/12 - Cold Case: The Mystery of the Melting Ice Cubes

Based on Raj's observation, which would be the most appropriate hypothesis?

• Ice melts faster in Milo compared to plain water.

• Ice melts faster when the temperature of the liquid is higher.

• Does ice melt faster in Milo compared to water?

• Does ice melt faster when the water is hotter?

Answer explanation

A hypothesis should be a statement and not a question.

Raj’s observation was about the ice cubes melting faster in his hot Milo as compared to his usual order of iced Milo. His observation is based around the temperature of the liquid and not the type of liquid.

Raj is setting up an experiment to test his hypothesis. What measures should he take to ensure this experiment is fair?

• The cups should be made of different materials (e.g. glass, plastic, etc.)

• The liquid in all 4 cups should be of different temperatures.

• There should be a different number of ice cubes in each cup.

• There should be different volumes of water in each cup.

Answer explanation

Since his hypothesis is centred around the temperature of the liquid, the independent variable in this experiment should be the temperature of the liquid.

All other variables should be controlled to keep this a fair experiment.

Which of the following devices is the most suitable for measuring the time taken for the ice cubes to melt completely?

• analog alarm clock

• hourglass

• IKEA analog clock in his living room

• stopwatch application on his iPhone

Answer explanation

The stopwatch application would be the most accurate option for measuring time in this case as it has higher precision and allows reading of milliseconds.

The stopwatch also enables Raj to stop and record the time unlike the other 3 options.

Raj's results showed that his hypothesis is true. What should he do next?

• Clean up and then rewatch all the Spiderman movies to celebrate.

• Repeat the experiment and analyse the consistency of both results.

• Restart the experiment with a brand new hypothesis.

• Tell everyone about his successful experiment.

Answer explanation

The experiment should always be repeated even if the hypothesis is proven true.

This increases the reliability of the results and ensures that the results are consistent.

If Raj's results showed that his hypothesis was not true, what should he do next?

• Check his experiment setup to see if all controlled variables are constant.

• Create a new hypothesis and start again.

• Give up, clean up and then rewatch all the Spiderman movies to cheer up.

• Lie and tell everyone that his experiment was successful.

Answer explanation

If the hypothesis is proven false, it is important to still repeat the experiment to see if the results are consistent.

However, before repeating the experiment, Raj should re-check his experiment setup to see if he made any errors and if all other variables are kept constant.

Any changes, if necessary, should be made before repeating the experiment.