Activity 1. Eureka!

Description:

Objetive:

To apply physical principles to determine the state of fluids.

Description:

In this activity you will apply the principles of Archimedes, Pascal and Bernoulli in three simple experiments.

Requirements:

Experiment 1

  • Stopwatch
  • Ruler
  • Access to a water faucet
  • Calculator
  • 1lt container

Experiment 2

  • 2 cylinders of modeling clay
  • 2 beakers
  • Weighing scale
  • Wide glass container
  • 3 markers (different colors)

Experiment 3

  • 1 syringe of 3ml
  • 1 syringe of 20ml
  • 50cm of transparent hose, Venofix type (must fit inside the syringes)
  • 1 object with a mass of 500gr
  • 80 ml of red oil for furniture
  • 1 photo and video camera
Instructions for the student:

Part 1

  1. According to your experience, describe what a fluid is.
  1. Draw a table and fill it with the properties of fluids, the usages or functions that you consider fluids have, as well as the principles that governs them.
  1. Share your work with a classmate and integrate the missing information to your table.

Part 2

  1. Gather in teams and do  the following experiments in the science laboratory, with the requested material and the one provided by your teacher:

Click on each experiment to know the information.

Experiment 1
  1. Take the time a water faucet takes to fill a 1 lt container.
  2. Measure the diameter of the faucet and calculate its area.
  3. Convert 1 liter to m3 and calculate the expense and the speed at which the water leaves the faucet.
  4. Repeat the experiment on a higher faucet and compare the speeds.
  5. Calculate the pressure difference of the two faucets using Bernoulli’s principle.
  6. Save the water for the next experiment.
Experiment 2
  1. Fill the glass container ¾ of its capacity.
  2. With a marker, draw a line in the container to indicate the original height of the water.
  3. Shape one cylinder of modeling clay into a sphere and put it in the container.
  4. Using a different marker, mark the rise of the water on the container and with a syringe remove the water (don’t remove the sphere) until it reaches the original height and put it in a beaker.
  5. Fill the container again up to the first mark and shape the modeling clay into a ship. The goal is to make the ship float maintaining the same mass.
  6. Once the ship floats, using the last marker, mark the rise of the water on the container and take the water out using a syringe. You need to do it until the water reaches its original height. Put it into another beaker.
  7. Using the scale, measure the mass the water of each beaker and the modeling clay. Then calculate the buoyant force exerted on the sphere and the boat. Compare it with the weight of the modeling clay.
Experiment 3
  1. Measure the area of the pistons of the syringes (A1 and A2).
  2. Fill the hose with red oil and join each side of the hose to each of the two syringes (which also have some red oil). The device should be so that squeezing out a syringe should push the other one.
  3. Place the object that has a mass of 500 g on the 3 ml syringe.
  4. Observe whether the large syringe plunger rises.

Calculate the following:

  • Syringe with a piston area of 3 ml.
  • Syringe plunger with an area of 20 ml.
  • The force applied in the 3 ml syringe according to the mass of 500 g which was placed on top: W = mg.

Using the Pascal’ principle, obtain the force on the plunger of the 20 ml syringe.

Part 3

  1. Based on the above, make a video about the results of the three experiments, using the laws to determine the state of the fluids that includes the following criteria:
    1. Experiment 1: Explanation of your results using the flow rate formula and Bernoulli’s principle.
    2. Experiment 2: Explain your results and how they agree with Archimedes’ principle.
    3. Experiment 3: relation of the results with the Pascal’s law and its applications, as well as the mechanic advantage of the device that you built with the syringes.
  2. Write your conclusions about the importance of physics to explain the fluids states.

Note for the student: consider that your activity must be documented (process) and supported.

Deliverable(s):

Video including the results obtained in the three experiments, as well as their explanation through principles and appropriate physical equations.

Evaluation criteria:
  1. Define the fluids properties and states, regarding the physical principles.
  2. Develop each experiment applying the necessary procedure and equations.
  3. Justify the obtained results of each experiment, mentioning the indicated criteria.
This activity is complemented with the readings and videos found in Blackboard.