Artists, architects, and engineers all use Pi, which is actually an infinite number (one that has no end) to help them calculate and create perfect circles or curves of specific sizes. This can help in everything from truck wheels to arches in buildings!
For more formulas that use pi, check out: http://www.mathgoodies.com/lessons/vol2/circumference.html
Pi is an infinite number! To see a million digits of pi, visit: http://mathforum.org/library/drmath/view/58312.html
You will need:
|| Test Your Blaster
What is the greatest distance you can be from a target and still hit it with the air?
How could you make a stronger air blaster?
What if you try different sizes of containers?
How about balloons that are stretched more or less taut?
The science that makes this work:
The physics of moving air is called fluid dynamics. Air is a fluid just like liquids. Hitting, tapping, or stretching and releasing the rubber membrane forces a sudden gush of air out the opening. The surrounding air is disturbed forming an invisible swirling and twisting of air similar in shape to a doughnut. Such twisting of air is called a vortex. In fact, some sciene theater performers making these rings of air visible using dry ice or a fog machine.
You will need:
1) Prepare your ice several hours or overnight before your experiment.
2) Feel the metal pan and cutting board with your hand. When you put your palm or fingers on it, does one of the surfaces feel warmer or colder than the other?
3) Make a prediction about which material will cause an ice cube to melt faster.
4) Take out two ice cubes. Place one on the pan and one on the cutting board at the same time.
5) Choose other materials to test how quickly they melt the ice. Feel the material and predict if it will melt the ice quickly or slowly, then place ice cubes on them and see if the results match your predictions. OPTIONAL: You might want to use a timer, to time your melting races, and make a chart for your predictions and results.
Do you notice a relationship between how warm or cool each material feels to your hand and how quickly it melts the ice?
Spoiler Alert: You may want to read this AFTER you have conducted all your tests.
You’ve probably noticed that the frying pan feels colder than the cutting board. They are both at room temperature, but even though the pan feels colder, it actually makes the ice melt faster!
When you touch the pan, the heat of your hand quickly transfers out of your hand and into the pan. This leaves your hand feeling cold. But when you touch the cutting board, only a little heat slowly flows into the board. So your hand still feels warm. Remember both the pan and cutting board are at room temperature, much warmer than an ice cube! Heat from the room transfers quickly through the pan into the ice cube, melting it very quickly. But heat only slowly transfers to the ice cube on the cutting board, making it melt more slowly.
The difference happens because of a property called thermal conductivity. Thermal conductivity measures how quickly heat flows through a material. Materials like aluminum, stainless steel and copper (materials that pans are usually made of) have a high thermal conductivity, while materials like plastic and Styrofoam (materials that are often used in things like ice chests) have a low thermal conductivity.