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Scientific Enquiry - Making predictions and drawing conclusions

Grade 3Cambridge (IGCSE)

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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A prediction is an educated guess about what will happen in an investigation based on prior scientific knowledge or patterns observed.

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A fair test is an experiment where only one variable is changed (the independent variable) while all other conditions are kept exactly the same.

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Observations involve using the five senses and scientific tools to collect data, such as measuring a liquid's volume in mlml or a plant's growth in cmcm.

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A conclusion is a final statement that explains what the results show and whether they support the original prediction.

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Data patterns help in drawing conclusions; for example, if the temperature of H2OH_2O increases, the rate of dissolving usually increases.

📐Formulae

Prediction→Investigation→Evidence→Conclusion\text{Prediction} \rightarrow \text{Investigation} \rightarrow \text{Evidence} \rightarrow \text{Conclusion}

Result=Observation+Measurement\text{Result} = \text{Observation} + \text{Measurement}

Change in Height=hfinal−hinitial\text{Change in Height} = h_{final} - h_{initial}

💡Examples

Problem 1:

Leo wants to see if the amount of light affects how tall a sunflower grows. He places one plant in the sun and one in a dark cupboard. He predicts the sunlit plant will grow more. After 10 days, the sunlit plant is 15 cm15\text{ cm} tall and the dark plant is 5 cm5\text{ cm} tall. Draw a conclusion.

Solution:

The plant in the sunlight grew taller (15 cm>5 cm15\text{ cm} > 5\text{ cm}), which supports the prediction.

Explanation:

By comparing the two measurements, we see a clear difference of 10 cm10\text{ cm}. This evidence confirms that light is necessary for healthy growth.

Problem 2:

A student is testing how fast salt dissolves in H2OH_2O. They use 50 ml50\text{ ml} of water at 10∘C10^\circ\text{C} and 50 ml50\text{ ml} of water at 40∘C40^\circ\text{C}. If they predict that heat speeds up the process, what result should they look for?

Solution:

The salt should dissolve in less time in the 40∘C40^\circ\text{C} water.

Explanation:

In scientific enquiry, 'faster' means the time (tt) taken for the process to complete is smaller (t40∘C<t10∘Ct_{40^\circ\text{C}} < t_{10^\circ\text{C}}).

Problem 3:

Identify the 'Fair Test' variables in an experiment where you measure how far a toy car rolls on different surfaces (carpet vs. wood).

Solution:

Keep the car type, the ramp height (hh), and the starting force (FF) the same; only change the surface.

Explanation:

To ensure the results are reliable, only the surface texture should change. If we changed the ramp height as well, we wouldn't know which change caused the car to move a different distance.

Making predictions and drawing conclusions Grade 3 Notes & Examples