What slows a falling object down?
The question
How does the size of a paper parachute affect the time it takes to fall?
A meteorite is slowed by air resistance so much that, for its last few kilometres, it falls at only a few hundred kilometres per hour or less, no longer glowing. This is called dark flight.
Equipment
- Paper or thin plastic bags cut into squares of 10, 20, 30 and 40 cm
- String or thread and sticky tape
- The same small weight for each parachute, such as a lump of modelling clay
- A stopwatch and a metre rule
Method
- Make four parachutes that are the same except for their size.
- Drop each one from the same height, at least 2 metres, from a safe place such as a staircase landing with an adult.
- Time how long it takes to reach the floor. Repeat three times and work out the average.
- Drop the weight on its own too.
- What to measure
- Fall time in seconds for each parachute size.
- How to present it
- A bar chart or line graph of fall time against parachute size, with your explanation of air resistance and a fact about dark flight.
- Take it further
- Keep the parachute size the same and change the weight. How do meteorite scientists use dark flight to work out where pieces landed?
Safety
Drop from a safe landing or balcony with a rail, with an adult. Never lean over a rail or stand on furniture.