Required Practicals: Biology Investigations

Ever wondered how fast your reaction time really is? RP7 tests this using a simple ruler drop method. Place your non-dominant hand over a table edge, have your partner hold a ruler between your fingers at the zero end, then catch it when they drop it without warning. Record where your thumb catches the ruler and repeat five times for accuracy.

Plant responses in RP8 show how seedlings react to light direction. Place 10 cress seeds in three petri dishes with moist filter paper, then shine light from different angles - above and from the sides. After a week, you'll see the plants grow towards the light source, demonstrating phototropism.

For field investigations (RP9), you've got two sampling methods. Random sampling uses coordinates from a number generator to place quadrats and count species. Continuous sampling involves laying a transect line and collecting data along its entire length to show how species change across different areas.

Top Tip: Always repeat measurements multiple times - it makes your results much more reliable and shows examiners you understand good scientific method.

The decay investigation (RP10) uses lipase enzyme to break down fats in milk. Mix milk with phenolphthalein indicator and sodium carbonate (turns pink), add lipase at different temperatures, then time how long it takes to turn white. Calculate the rate using 1000/time to see how temperature affects enzyme activity.