Physics 2015 Archimedes Principle Minilab 10 Archimedes Principle

Physics 2015 – Archimedes’ Principle Minilab 10 Archimedes’ Principle Department of Physics & Astronomy Page 1

Physics 2015 – Archimedes’ Principle The purpose of today’s lab is to investigate Archimedes’ Principle and buoyant forces. First, we will determine the density of metal balls of the same substance, but different radii. Then, once this density is known, we will use a metal slug (made of the same metal) to find the buoyant force of 4 different substances. PURPOSE Department of Physics & Astronomy Page 2

Physics 2015 – Archimedes’ Principle Activity 1 - Finding Density • Force sensor (on the stand) • Beaker with aluminum “basket” (place the metal balls in here) • Glass cylinder filled with water Make sure that you only put water inside the tall glass cylinders – NO other liquid goes in here! EQUIPMENT Department of Physics & Astronomy Page 3

Physics 2015 – Archimedes’ Principle Activity 2 - Finding Fluid Density • You will find 4 different plastic containers full of the following substances: • • Tap Water Salt Water Corn Syrup Isopropyl Alcohol (70%) • Attach the metal slug to the end of the force sensor, and place it into the substances to see how much force acts on the slug. EQUIPMENT Department of Physics & Astronomy Page 4

Physics 2015 – Archimedes’ Principle is straightforward: • An object that is submerged in a liquid will experience an additional upward force equal to the weight of the amount of liquid that was displaced by the object. This is called the buoyant force. Translated into English, this means: • Extra force acts on an object when it is placed in water. This makes the objects appear lighter than they really are. THEORY Department of Physics & Astronomy Page 5

Physics 2015 – Archimedes’ Principle THEORY Department of Physics & Astronomy Page 6

Physics 2015 – Archimedes’ Principle T W Department of Physics & Astronomy THEORY Page 7

Physics 2015 – Archimedes’ Principle THEORY Department of Physics & Astronomy Page 8

Physics 2015 – Archimedes’ Principle There is one more idea you will want to consider before starting the lab • Remember to “Tare” your force sensor before any procedure. In this case, tare the sensor AFTER YOU PUT THE BASKET ON THE SENSOR for Activity 1. This will negate the weight of the basket on your experiment! • When you graph this in Excel, you should expect the line to go through the origin. Why do you think this is? THEORY Department of Physics & Astronomy Page 9

Physics 2015 – Archimedes’ Principle PROCEDURE Department of Physics & Astronomy Page 10

Physics 2015 – Archimedes’ Principle Activity 2 • Tie the metal slug onto the force sensor, THEN tare it! (like the left picture) • You can then place the Tare slug into the different substances (like the right picture) PROCEDURE Department of Physics & Astronomy Page 11

Physics 2015 – Archimedes’ Principle PROCEDURE Department of Physics & Astronomy Page 12

Physics 2015 – Archimedes’ Principle • DO NOT POUR ANYTHING BUT WATER down the drain! • DO NOT POUR ANYTHING BUT WATER into the tall glass cylinders! • Clean up anything that spills IMMEDIATELY! These can damage equipment in the lab! Use a paper towel or a sponge • Put the cardboard covers back on the plastic beakers before you leave. FINAL REMINDERS Department of Physics & Astronomy Page 13