5th Grade Science Project Idea for kids

5th Grade Science Project Idea #1 

Make your own Hot Air Balloon 

Hot Air Balloon is a an awesome science experiment to demonstrate that hot air is less dense than cold air and how this principle was used to fly people in the 18th century and had become the first flying machine.

Kids can build a working model of a Hot Air Balloon with simple materials: Plastic Poly Bag, Aluminum Foil, Candles, Straws and Glue.

Step-by-Step Instructions along with the materials required are available in the Video below:

Working Principle of Hot Air Balloon 

A hot air balloon consists of a bag called the 'envelope' which contains the air heated by the flame of the candles at the bottom. The bottom of the envelope is open and as the temperature of the air rises - the warm air starts going towards the top of the balloon. This process is called convection. We see it in liquids - when we heat water, the hot water goes up and the cold water comes down. This happens as the density of warm air is less than the density of cold air. This is because, when the air is heated, the air molecules start to move more randomly as heat gives them more energy and they are spaced far away from each other which lowers the density.

Even though the bottom of the envelop is open, the warm air does not escape as it is trapped by the poly bag towards the top.

Now the question is, since we know whats happening inside the balloon/envelope -

Why does it fly ?

The balloon will fly only when the density of the warm air inside the balloon + weight of the envelop + weight of the candles and straws is less than the density of the air around/outside the balloon. 

This can be checked when the kids conduct this experiment and try it with different number of candles and analyse what works out the best.

Any Questions ?

Get in touch with us from our website www.zlifeeducation.com and email us the pictures/recordings of your experiment at our email ID mentioned on the website and we would be glad to assist you with your questions. 

More information on Fun Science Experiments for Kids to do at Home :

This experiment along with many others - are a part of the Monthly Science Box Program of Zlife Education where kids aged 7 - 12 yrs get new tools and experiments shipped every month at their door step .

100+  Fun Science Experiment Videos are also available at our You Tube Channel : Science with Zlife Education.