How does air pressure work? This collapsing can experiment will show you how 

Scientific concepts are best grasped by kids when demonstrated practically through experimentation. Not only does this help them understand the concepts more clearly, it is also fun and engaging! With the use of aluminium soda cans, this DIY experiment showcases exactly how air pressure works. Read on to find out how you and your budding scientist can conduct this experiment at home. 

What you will need 
Help your budding scientist gather these supplies from around the house and lay them on your kitchen counter. 

• 4 aluminium soda cans 
• A frying pan 
• A stove  
• Water 
• Tongs 
• Two glass bowls 
• Ice cubes 

Step-by-step guide  
Encourage your little scientist to follow these guidelines. Make sure to supervise while conducting this experiment as it makes use of a stove.  

• Fill two aluminium soda cans with some water. The water should ideally just cover the bottom of the cans- about half an inch is sufficient. More water will require a longer time to boil, and hence, the experiment would not be as much fun. 
• Place both the cans on a frying pan. Heat them until the water inside comes to a boil. 
• As the water in these cans is boiling, fill two bowls with ice cubes and ice cold water. Ensure that these bowls are filled with ice. 
• As soon as you notice steam rising from the cans, transfer one of them to the ice bowl using tongs. Be careful while doing so and ensure that the can is placed upside down. You will see that it collapses instantly. 
• Using the tongs, transfer the second can to the bowl. However, this time, place it right side up instead. You will notice that no change occurs. 

What exactly is happening in this experiment? 
As the water inside the cans is boiling, it starts to transform into steam. Steam is nothing but water in gaseous state, and it also takes up more space than liquid water. The can gets filled with this steam, and starts pushing out all the air from within it.  

When the first can is placed in the ice bowl upside down, the steam cools down and turns into water again and naturally, it occupies less space in its liquid form. Since the opening of the can is submerged in the ice bowl, there is no space for air to fill into it. As a consequence, the air outside of it exerts pressure, causing the can to collapse. 

As against this, with the second can which is placed upright in the ice bowl, no change occurs. This is because the outside air could enter the can through the can opening. The pressure inside it and outside it is equalised, causing the can to remain stable.