Pressure

• Pressure
• Newton

F = MA

• 1N = is about the amount or force needed to hold a medium sized apple
• An adult heart generates 7-10N with each pump.
• Pressing a key on a keyboard is a few N
• Holding a tennis ball is about 10N
• Moving your water bottle is about 10N

Pressure is a measure of force to an area

P = F/A

1 Pascal = 1 Newton over an area of 1 metre squared

1 kilopascal = 1000 p

• 50 psi = 344.74 kpa
• 30 psi = 206.34
• At sea level 101,325 Pascals (101.3 kPa).
• Teen blood pressure Systolic Pressure:12,000 to 21,000 Pascals. Diastolic Pressure: 8,000 to to 14,000 Pascals.

Pascal's Law

Pressure applied to an enclosed fluid/gas is transmitted equally in all directions throughout the fluid

Hydraulic = fluid

Pneumatic = air

compressible?

Pascal's Law and MA

MA = it’s the size of each piston (surface area)

Force of small piston/area of small piston = force of large piston/area of large piston

What is the cost for a small piston to move a larger one ?

Activities

• Cue tip blowgun
• Pressure Rocket you build - more interesting
• Vacuum Syringe Rocket - easy
• Fill bike tires - easy

Soon

• Before the siege engines begin, we’ll be playing with hydraulic machines.
• These kits are made by the same company as the siege engine models.