Pressure Bottle

1. What is the engineering principle that the children will learn? 

   This project will allow children to learn about principles of pressure as it relates to the temperature of the liquid. They will learn that by understanding how pressure acts, they can in turn predict the weather using a barometer.  

    

2. What is the activity? 

   This activity consists of play dough or clay, a glass bottle, a strong clear straw, water, and food coloring. Water is heated and placed inside the glass bottle.  A few drops of food coloring are added to the water in the bottle.  The straw is then placed inside the bottle and used to stir the food coloring and the water.  By either sucking or some other form of suction, the children will raise the level of the water so that it is above the rest of the water in the bottle.  With their finger, they will temporarily plug the top of the straw with their finger so that the water remains above the normal water level.  While keeping the top of the straw closed with their finger, the children will then place the play dough or clay around the straw and the top of the bottle in order to form an airtight seal.  Once this is accomplished, the children may then let go of the straw and watch the water level change as the water cools.  To see this happen rapidly, the bottle can be placed inside of a bowl with cold water from the tap.  The children might want to mark on the side of the bottle were the original water level was in the straw so they can see how the level has changed.  This, along with some explanation, will allow them to see pressure principles at work. 

    

3. What age group is this activity designed for? 

   Middle school students should be able to grasp the concepts fairly easily. Older elementary students might enjoy the activity too.  

    

4. What will the children do and how will they learn by doing your activity? 

   The children will basically make the entire barometer apparatus. However, it will be somewhat difficult for them to grasp all the concepts behind the system without some explanations. After a thorough explanation, the students should be able to understand why the water level in the straw moves up and down. 

    

5. What will be in your activity box? If appropriate, include a sketch of the activity. 
   • Play dough or clay
   • Glass bottle
   • Strong, clear straw
   • Food coloring
   • Electric hot pot

    

6. How does your activity meet the requirements given above? 

   This activity merely shows them the concept of pressure. The changing water levels can easily be related to hydraulic lifts and other such devices. This is quite safe and non-toxic to children, with no sharp or hot parts. This will occupy children for approximately 20-30 minutes, not including explanation time. 30 of these activity kits should easily fit within a compact car.