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===About Upthrust===
: [[Upthrust]] is a [[force]] so it is [[Measure|measured]] in [[Newton]]s.
: The [[force]] of [[upthrust]] is equal to the [[weight]] of [[fluid]] that has been [[Displace|displaced]] by an [[object]].: An [[object]] in the [[water]] experiences as lot of more [[upthrust]] than an [[object]] in [[air]] because [[water]] is more [[Density|dense]] than [[air]].
: [[Upthrust]] is weak in the [[air]] because the [[air]] is not very [[Density|dense]]. For most [[object]]s in [[air]] [[upthrust]] can be ignored because it is so small.
: [[Upthrust]] is caused by the [[pressure]] in a [[fluid]]. [[Pressure]] increases with [[depth]] so the bottom of an [[object]] will experience more [[pressure]] than the top. This difference in [[pressure]] results in a difference between the [[force]] on the bottom and the top, known as [[upthrust]].
===Examples===
{| class="wikitable"
|-
|[[File:UpthrustBoat.png|center|250px]]
|[[File:UpthrustSubmarine.png|center|300px]]
|-
| style="height:20px; width:300px; text-align:center;" |A boat floats on the water because the [[weight]] is balanced by the [[upthrust]].
| style="height:20px; width:300px; text-align:center;" |A submarine can change the amount of [[upthrust]] in order to rise or sink in the [[water]].
|}
==Key Stage 4 Foundation==
===Meaning===
[[Upthrust]] is a [[force]] that acts upwards in a [[fluid]] due to the [[fluid]] being [[Displace|displaced]].
===About Upthrust===
: [[Upthrust]] is a [[force]] so it is [[Measure|measured]] in [[Newton]]s.
: The [[force]] of [[upthrust]] is equal to the [[weight]] of [[fluid]] that has been [[Displace|displaced]] by an [[object]].
: An [[object]] in the [[water]] experiences more [[upthrust]] than an [[object]] in [[air]] because [[water]] is more [[Density|dense]] than [[air]].
: [[Upthrust]] is weak in the [[air]] because the [[air]] is not very [[Density|dense]]. For most [[object]]s in [[air]] [[upthrust]] can be ignored because it is so small.
: [[Upthrust]] is caused by the [[pressure]] in a [[fluid]]. [[Pressure]] increases with [[depth]] so the bottom of an [[object]] will experience more [[pressure]] than the top. This difference in [[pressure]] results in a difference between the [[force]] on the bottom and the top, known as [[upthrust]].
===Key Stage 4 Higher===
===Calculating Upthrust===
''NB: You don not need to remember this equation.''
Upthrust = (Density of the fluid) x (Gravitational Field Strength) x (Object Height) x (Cross sectional area perpendicular to the height)
<math> F_U = \rho g h A</math>
Where:
<math> F_U</math> = [[Force]] of [[upthrust]].
<math>\rho</math> = [[Density]] of [[fluid]].
<math>g</math> = [[Gravitational Field Strength]]
<math>h</math> = [[Height]] of [[object]] from top to bottom.
<math>A</math> = [[Cross Sectional Area|Cross sectional area]] of the [[object]] [[perpendicular]] to the [[height]].
===Example Calculations===
===Examples===
{| class="wikitable"