Cambridge Secondary (7-9). Stage 8. Science. Learner's Book - Unit 3: Forces and energy - Question 141

Think like a scientist: The effect of temperature on the speed of diffusion. In this investigation, you will investigate how temperature affects the speed of diffusion in liquids. Work in groups of two or three. You will need: three or more identical beakers; water; a way to heat the water; a way to cool the water (optional); water-soluble ink or food dye; measuring cylinder; thermometer; dropper pipette; stopwatch. Method: 1 Add equal volumes of water at different temperatures to each of your beakers. 2 Measure and record the temperature of the water in each beaker. 3 Use the dropper pipette to carefully add a small volume of ink or food dye to the bottom of each beaker. Squeeze the top of the pipette gently so it does not squirt out into the water and start mixing. Add the ink or food dye to the water in order from the lowest to the highest temperature. 4 Use a stopwatch to time the diffusion process in each beaker. 5 Stop the stopwatch when the ink or food dye has fully spread out through the water of the beaker being tested.

Explain this trend.