Overview
This lesson covers a parachute experiment focused on testing how parachute size affects the time it takes to fall, introducing concepts like hypothesis, fair testing, air resistance, and friction.
Formulating the Hypothesis
- The hypothesis is a prediction of which parachute (smaller or larger) will fall to the ground faster or slower.
- You should write the hypothesis before starting the experiment.
Materials and Preparation
- Use a plastic bag or trash bag to make parachutes (trash bags are larger and easier to cut).
- Cut two large squares (30 cm x 30 cm) from the plastic or trash bag.
- Use a long ruler for accurate measurement.
- Cut two pieces of string, each 45 cm long, per parachute.
- Label the corners of the square A, B, C, and D in clockwise direction.
- Tie a knot at each corner, close to the edge.
- Attach strings to each corner and secure a weighted object (like a sweet or eraser) in the middle.
Experiment Steps
- Ensure the attached weight has the same mass for each parachute to keep the test fair.
- The strings must be of equal length from all four corners to the center.
- Drop the parachutes from the same height to avoid bias.
Observations and Explanation
- Observe which parachute takes longer to fall.
- Typically, the larger the parachute, the longer it takes to reach the ground.
- A larger parachute has more exposed surface area, increasing air resistance.
- Air resistance pushes against the parachute, slowing its fall.
Forces and Air Resistance
- Air resistance is a type of friction force acting against the movement of the parachute.
- Friction occurs when one surface rubs against another, always opposing motion.
- More surface area creates more air resistance, causing a slower descent.
Key Terms & Definitions
- Hypothesis — A prediction about the outcome of the experiment.
- Air Resistance — A force that opposes the motion of objects through air, also known as drag.
- Friction — The force when two surfaces rub against each other, opposing motion.
- Fair Test — An experiment where only one variable is changed at a time.
Action Items / Next Steps
- Complete cutting and assembling parachutes as described.
- Write down your hypothesis and precautions taken.
- Conduct the experiment and record your observations.