Sugar Aunts: Experiments with Air Drag and Streamlined Shapes

## Experiments with Air Drag and Streamlined Shapes

Today's experiment with streamlined vehicles and shapes was a very fun way to learn about air drag!  My son loves anything with experiments or discovery, so this STEM (Science, Technology, Engineering, Math) activity was right up his alley.  We discovered why sports cars have pointed fronts and a little about how an object's shape affects it's movement with drag and airflow.

## Experimenting with Air Drag and Streamlined Vehicles

We used just a few materials for this experiment (I'm including the affiliate links for your convenience.)
You'll need:
Two identical toy cars.  We used ones similar to these.
colored cardstock, cut into rectangles

stack of books

This is an easy STEM activity to set up.  Cut the cardstock into strips that are as wide as the cars.  You'll want the length to be a little longer than the cars, but even with the end.  I taped the edge of the cardstock rectangle to the front of each car, then bent one into a curved shape and the other into an right angle shape.  The cardstock is a good material for this experiment because it holds the curve and angled shapes well.  Regular paper will not work as well.  Finally, snip the edge of the cardstock so that it ends at the end of each car.

Prediction:  Ask your child their predictions!  What will the shapes do to the cars?  Will one shape go faster? Why?  What will happen when air is applied to the cars?

Now comes the fun part: the streamlined shapes experiment!

Stack a few books and prop one end of the foam board up.  You can use any flat surface for this project, but the foam board was the right length and perfect for both cars to travel without sailing over the edge.

First line each car up on the edge of the foam board.  This is a fun activity in itself; sending toy cars down planks and ramps is a great boredom buster!

Experiment with force, but just tapping the cars down the ramp and pushing.  More force gives them more speed!  We noticed that both cars went down the ramp at the same time.   Be sure to push the cars over the edge of the ramp at exactly the same time.

Next, we applied a source of air to the bottom of the ramp.  Turn on the hair dryer and aim the air toward the cars going down the ramp.  Now, the curved car went faster!

What is happening?  The car with the streamlined shape travels faster because it's shape disturbs less of the air.  The car with the angular shape disturbs air as it travels.  This unstreamlined shape increases the force called drag and slows the car down.

### What is drag? Drag is air resistance caused by disturbances in the flow of air over an object.  This force slows down moving objects like the cars in our experiment.

Have fun with your air flow experiments!  You might also like our Bernoulli's Principle air glider project: