Week 3 - Does the shape of an object affect its movement in a liquid?
Last week we did an experiment to show that there is a force called air resistance which slows down objects which are moving through air. Below is the video of Brian Cox dropping feathers and a heavy ball in a vacuum chamber. Because there is no air in the room, there is no air resistance so both objects fall at the same speed, even though they are different weights.
Can you run better in air than water? Why is this? It is harder to run in water because of a force called water resistance. Water resistance slows objects down as they move through water and is similar to air resistance as objects travel through air. It is the force of water which pushes back against an object moving through it. Boats, submarines and any other objects which travel through water are affected by water resistance, even fish! The shape of the object is what determines the amount of water resistance which is very similar to air resistance which we learnt about last week. The more streamlined the object is, the less resistance it has.
Task 1: Please watch the video below:
Task 2: Your written task today is to answer the questions on the sheet below. The experiment explores the effect different shaped boats have on the time it takes for them to travel along some guttering. Which one do you think would be fastest?
If you finish early, I would like you to design a streamlined vehicle, boat, plane or animal. It can be completely imaginary but must have as little water or air resistance as possible.Please colour and label your diagram.
Here is a summary about air and water resistance:
Task 3: This is a video of a similar experiment to the one we would normally have been completing in class. Please watch it. www.bbc.co.uk/education/clips/zxqd7ty
Extension activity: With your parent's permission, have a go at the experiment you have just watched. I sometimes replace the water with translucent bubble bath to slow the objects down to make it easier to see the winner. Have fun!