Name: _____________________ Wire Resistance and Ohm’s Law PhET MiniLab Introduction: When an electrical potential exists in a circuit, a current may flow. Current is the flow of electrons in a circuit. Resistance in the circuit slows the flow of the electrons, reducing the current in the circuit. We will use the mathematical form of Ohm’s Law frequently when we investigate electric current and circuits later in this unit. Additional Material Needed: Clean Drinking Straw Procedure Part I Wire Resistance: • Blow through the drinking straw. • Cut the drinking straw in half and blow through a half-straw. • Describe the effect of length on ease to blow air through the straw. _________________________________________ • Cut the halves again in half. • With the four pieces, blow through one, then blow through all four made into a larger, square-shaped straw. • Describe the effect of straw size (diameter) on ease to blow air through the straw. ______________________________ • Now, open the PhET Simulation Electricity, Magnets, and Circuits  Resistance in a Wire As wire length (cm) increases, the resistance (Ω) _________________ As wire area (cm2) increases, the resistance (Ω) __________________ As wire density (Ωcm) increases, the resistance (Ω) _______________ Procedure Part II: Ohm’s Law: Electricity, Magnets, and Circuits  Ohm’s Law mA is milliamps, and _________ milliamps equals one Ampere. • Move the potential (volts) and resistance (ohms) sliders and observe the current (amps) As voltage increases, current __________________. As resistance increases, current ________________. Fill out the tables below and check your work in the simulation. ( ½ pt each ) • Remember, the simulation shows milliamps. • You should show Amperes V = I * R 8.0 V A 800 Ω 2.0 V .044 A Ω V .0058 A 430 Ω V .069 A 100 Ω 6.4 V A 300 Ω Conclusion Questions: ( ½ pt each) 1. Incandescent light bulbs have a very thin filament that glows when hot. Thin filaments have very high / low resistance. 2. The 12V battery in your car operates a 25 amp car stereo. What is the resistance of this stereo system? ___________ 3. A “2D” Maglite flashlight runs on 3.0V. What is the current through the bulb if resistance is 15 Ω ? ____________ 4. How many volts must an iPod charger provide to charge an iPOD using .85 Amps at 35 Ω? _____________ 5. You need to buy a long extension cord to power a stereo at your spring break BBQ. You need 200feet. You have a 50 ft cord that will work. You rationalize that four such 50 ft cords will do the job. Is this a good idea? Why or Why not? ___________________________________________________________________________________________

Name: _____________________ Wire Resistance and Ohm’s Law PhET MiniLab Introduction: When an electrical potential exists in a circuit, a current may flow. Current is the flow of electrons in a circuit. Resistance in the circuit slows the flow of the electrons, reducing the current in the circuit. We will use the mathematical form of Ohm’s Law frequently when we investigate electric current and circuits later in this unit. Additional Material Needed: Clean Drinking Straw Procedure Part I Wire Resistance: • Blow through the drinking straw. • Cut the drinking straw in half and blow through a half-straw. • Describe the effect of length on ease to blow air through the straw. _________________________________________ • Cut the halves again in half. • With the four pieces, blow through one, then blow through all four made into a larger, square-shaped straw. • Describe the effect of straw size (diameter) on ease to blow air through the straw. ______________________________ • Now, open the PhET Simulation Electricity, Magnets, and Circuits  Resistance in a Wire As wire length (cm) increases, the resistance (Ω) _________________ As wire area (cm2) increases, the resistance (Ω) __________________ As wire density (Ωcm) increases, the resistance (Ω) _______________ Procedure Part II: Ohm’s Law: Electricity, Magnets, and Circuits  Ohm’s Law mA is milliamps, and _________ milliamps equals one Ampere. • Move the potential (volts) and resistance (ohms) sliders and observe the current (amps) As voltage increases, current __________________. As resistance increases, current ________________. Fill out the tables below and check your work in the simulation. ( ½ pt each ) • Remember, the simulation shows milliamps. • You should show Amperes V = I * R 8.0 V A 800 Ω 2.0 V .044 A Ω V .0058 A 430 Ω V .069 A 100 Ω 6.4 V A 300 Ω Conclusion Questions: ( ½ pt each) 1. Incandescent light bulbs have a very thin filament that glows when hot. Thin filaments have very high / low resistance. 2. The 12V battery in your car operates a 25 amp car stereo. What is the resistance of this stereo system? ___________ 3. A “2D” Maglite flashlight runs on 3.0V. What is the current through the bulb if resistance is 15 Ω ? ____________ 4. How many volts must an iPod charger provide to charge an iPOD using .85 Amps at 35 Ω? _____________ 5. You need to buy a long extension cord to power a stereo at your spring break BBQ. You need 200feet. You have a 50 ft cord that will work. You rationalize that four such 50 ft cords will do the job. Is this a good idea? Why or Why not? ___________________________________________________________________________________________

The term used to describe the cell taking in large amounts of liquid, also known as cell drinking, is, phagocytosis, hydration, pinocytosis, dehydration, none of the above.

The term used to describe the cell taking in large amounts of liquid, also known as cell drinking, is, phagocytosis, hydration, pinocytosis, dehydration, none of the above.

The term used to describe the cell taking in large … Read More...
Researchers recently investigated whether or not coffee prevented the development of high blood sugar (hyperglycemia) in laboratory mice. The mice used in this experiment have a mutation that makes them become diabetic. Read about this research study in this article published on the Science Daily web-site New Evidence That Drinking Coffee May Reduce the Risk of Diabetes as well as the following summary: A group of 11 mice was given water, and another group of 10 mice was supplied with diluted black coffee (coffee:water 1:1) as drinking fluids for five weeks. The composition of the diets and living conditions were similar for both groups of mice. Blood glucose was monitored weekly for all mice. After five weeks, there was no change in average body weight between groups. Results indicated that blood glucose concentrations increased significantly in the mice that drank water compared with those that were supplied with coffee. Finally, blood glucose concentration in the coffee group exhibited a 30 percent decrease compared with that in the water group. In the original paper, the investigators acknowledged that the coffee for the experiment was supplied as a gift from a corporation. Then answer the following questions in your own words: 1. Identify and describe the steps of the scientific method. Which observations do you think the scientists made leading up to this research study? Given your understanding of the experimental design, formulate a specific hypothesis that is being tested in this experiment. Describe the experimental design including control and treatment group(s), and dependent and independent variables. Summarize the results and the conclusion (50 points) 2. Criticize the research described. Things to consider: Were the test subjects and treatments relevant and appropriate? Was the sample size large enough? Were the methods used appropriate? Can you think of a potential bias in a research study like this? What are the limitations of the conclusions made in this research study? Address at least two of these questions in your critique of the research study (20 points). 3. Discuss the relevance of this type of research, both for the world in general and for you personally (20 points). 4. Write answers in your own words with proper grammar and spelling (10 points)

Researchers recently investigated whether or not coffee prevented the development of high blood sugar (hyperglycemia) in laboratory mice. The mice used in this experiment have a mutation that makes them become diabetic. Read about this research study in this article published on the Science Daily web-site New Evidence That Drinking Coffee May Reduce the Risk of Diabetes as well as the following summary: A group of 11 mice was given water, and another group of 10 mice was supplied with diluted black coffee (coffee:water 1:1) as drinking fluids for five weeks. The composition of the diets and living conditions were similar for both groups of mice. Blood glucose was monitored weekly for all mice. After five weeks, there was no change in average body weight between groups. Results indicated that blood glucose concentrations increased significantly in the mice that drank water compared with those that were supplied with coffee. Finally, blood glucose concentration in the coffee group exhibited a 30 percent decrease compared with that in the water group. In the original paper, the investigators acknowledged that the coffee for the experiment was supplied as a gift from a corporation. Then answer the following questions in your own words: 1. Identify and describe the steps of the scientific method. Which observations do you think the scientists made leading up to this research study? Given your understanding of the experimental design, formulate a specific hypothesis that is being tested in this experiment. Describe the experimental design including control and treatment group(s), and dependent and independent variables. Summarize the results and the conclusion (50 points) 2. Criticize the research described. Things to consider: Were the test subjects and treatments relevant and appropriate? Was the sample size large enough? Were the methods used appropriate? Can you think of a potential bias in a research study like this? What are the limitations of the conclusions made in this research study? Address at least two of these questions in your critique of the research study (20 points). 3. Discuss the relevance of this type of research, both for the world in general and for you personally (20 points). 4. Write answers in your own words with proper grammar and spelling (10 points)

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1. Develop a thought experiment that attempts to uncover hidden assumptions about human freedom. 2. Find a paragraph from a book, magazine, ect. First, tell whether there are claims in the paragraph. If there are, identify the types of claims (descriptive, normative, a priori, a posteriori) in the paragraph

1. Develop a thought experiment that attempts to uncover hidden assumptions about human freedom. 2. Find a paragraph from a book, magazine, ect. First, tell whether there are claims in the paragraph. If there are, identify the types of claims (descriptive, normative, a priori, a posteriori) in the paragraph

Let us think of a thought experiment that wants to … Read More...
Question 1, chap 33, sect 3. part 1 of 2 10 points The compound eyes of bees and other insects are highly sensitive to light in the ultraviolet portion of the spectrum, particularly light with frequencies between 7.5 × 1014 Hz and 1.0 × 1015 Hz. The speed of light is 3 × 108 m/s. What is the largest wavelength to which these frequencies correspond? Question 3, chap 33, sect 3. part 1 of 3 10 points A plane electromagnetic sinusoidal wave of frequency 10.7 MHz travels in free space. The speed of light is 2.99792 × 108 m/s. Determine the wavelength of the wave. Question 4, chap 33, sect 3. part 2 of 3 10 points Find the period of the wave. Question 2, chap 33, sect 3. part 2 of 2 10 points What is the smallest wavelength? Question 5, chap 33, sect 3. part 3 of 3 10 points At some point and some instant, the electric field has has a value of 998 N/C. Calculate the magnitude of the magnetic field at this point and this instant. Question 6, chap 33, sect 3. part 1 of 2 10 points A plane electromagnetic sinusoidal wave of frequency 10.7 MHz travels in free space. The speed of light is 2.99792 × 108 m/s. Determine the wavelength of the wave. Question 8, chap 33, sect 3. part 1 of 1 10 points The magnetic field amplitude of an electromagnetic wave is 9.9 × 10−6 T. The speed of light is 2.99792 × 108 m/s . Calculate the amplitude of the electric field if the wave is traveling in free space. Question 7, chap 33, sect 3. part 2 of 2 10 points At some point and some instant, the electric field has has a value of 998 V/m. Calculate the magnitude of the magnetic field at this point and this instant. Question 9, chap 33, sect 5. part 1 of 1 10 points The cable is carrying the current I(t). at the surface of a long transmission cable of resistivity ρ, length ℓ and radius a, using the expression ~S = 1 μ0 ~E × ~B . Question 10, chap 33, sect 5. part 1 of 1 10 points In 1965 Penzias and Wilson discovered the cosmic microwave radiation left over from the Big Bang expansion of the universe. The energy density of this radiation is 7.64 × 10−14 J/m3. The speed of light 2.99792 × 108 m/s and the permeability of free space is 4π × 10−7 N/A2. Determine the corresponding electric field amplQuestion 11, chap 33, sect 5. part 1 of 5 10 points Consider a monochromatic electromagnetic plane wave propagating in the x direction. At a particular point in space, the magnitude of the electric field has an instantaneous value of 998 V/m in the positive y-direction. The wave is traveling in the positive x-direction. x y z E wave propagation The speed of light is 2.99792×108 m/s, the permeability of free space is 4π×10−7 T ・ N/A and the permittivity of free space 8.85419 × 10−12 C2/N ・ m2. Compute the instantaneous magnitude of the magnetic field at the same point and time.itude. Question 12, chap 33, sect 5. part 2 of 5 10 points What is the instantaneous magnitude of the Poynting vector at the same point and time? Question 13, chap 33, sect 5. part 3 of 5 10 points What are the directions of the instantaneous magnetic field and theQuestion 14, chap 33, sect 5. part 4 of 5 10 points What is the instantaneous value of the energy density of the electric field? Question 16, chap 33, sect 6. part 1 of 4 10 points Consider an electromagnetic plane wave with time average intensity 104 W/m2 . The speed of light is 2.99792 × 108 m/s and the permeability of free space is 4 π × 10−7 T・m/A. What is its maximum electric field? What is the instantaneous value of the energy density of the magnetic field? Question 17, chap 33, sect 6. part 2 of 4 10 points What is the the maximum magnetic field? Question 19, chap 33, sect 6. part 4 of 4 10 points Consider an electromagnetic wave pattern as shown in the figure below. Question 18, chap 33, sect 6. part 3 of 4 10 points What is the pressure on a surface which is perpendicular to the beam and is totally reflective? Question 20, chap 33, sect 8. part 1 of 1 10 points A coin is at the bottom of a beaker. The beaker is filled with 1.6 cm of water (n1 = 1.33) covered by 2.1 cm of liquid (n2 = 1.4) floating on the water. How deep does the coin appear to be from the upper surface of the liquid (near the top of the beaker)? An cylindrical opaque drinking glass has a diameter 3 cm and height h, as shown in the figure. An observer’s eye is placed as shown (the observer is just barely looking over the rim of the glass). When empty, the observer can just barely see the edge of the bottom of the glass. When filled to the brim with a transparent liquid, the observer can just barely see the center of the bottom of the glass. The liquid in the drinking glass has an index of refraction of 1.4 . θi h d θr eye Calculate the angle θr . Question 22, chap 33, sect 8. part 2 of 2 10 points Calculate the height h of the glass.

Question 1, chap 33, sect 3. part 1 of 2 10 points The compound eyes of bees and other insects are highly sensitive to light in the ultraviolet portion of the spectrum, particularly light with frequencies between 7.5 × 1014 Hz and 1.0 × 1015 Hz. The speed of light is 3 × 108 m/s. What is the largest wavelength to which these frequencies correspond? Question 3, chap 33, sect 3. part 1 of 3 10 points A plane electromagnetic sinusoidal wave of frequency 10.7 MHz travels in free space. The speed of light is 2.99792 × 108 m/s. Determine the wavelength of the wave. Question 4, chap 33, sect 3. part 2 of 3 10 points Find the period of the wave. Question 2, chap 33, sect 3. part 2 of 2 10 points What is the smallest wavelength? Question 5, chap 33, sect 3. part 3 of 3 10 points At some point and some instant, the electric field has has a value of 998 N/C. Calculate the magnitude of the magnetic field at this point and this instant. Question 6, chap 33, sect 3. part 1 of 2 10 points A plane electromagnetic sinusoidal wave of frequency 10.7 MHz travels in free space. The speed of light is 2.99792 × 108 m/s. Determine the wavelength of the wave. Question 8, chap 33, sect 3. part 1 of 1 10 points The magnetic field amplitude of an electromagnetic wave is 9.9 × 10−6 T. The speed of light is 2.99792 × 108 m/s . Calculate the amplitude of the electric field if the wave is traveling in free space. Question 7, chap 33, sect 3. part 2 of 2 10 points At some point and some instant, the electric field has has a value of 998 V/m. Calculate the magnitude of the magnetic field at this point and this instant. Question 9, chap 33, sect 5. part 1 of 1 10 points The cable is carrying the current I(t). at the surface of a long transmission cable of resistivity ρ, length ℓ and radius a, using the expression ~S = 1 μ0 ~E × ~B . Question 10, chap 33, sect 5. part 1 of 1 10 points In 1965 Penzias and Wilson discovered the cosmic microwave radiation left over from the Big Bang expansion of the universe. The energy density of this radiation is 7.64 × 10−14 J/m3. The speed of light 2.99792 × 108 m/s and the permeability of free space is 4π × 10−7 N/A2. Determine the corresponding electric field amplQuestion 11, chap 33, sect 5. part 1 of 5 10 points Consider a monochromatic electromagnetic plane wave propagating in the x direction. At a particular point in space, the magnitude of the electric field has an instantaneous value of 998 V/m in the positive y-direction. The wave is traveling in the positive x-direction. x y z E wave propagation The speed of light is 2.99792×108 m/s, the permeability of free space is 4π×10−7 T ・ N/A and the permittivity of free space 8.85419 × 10−12 C2/N ・ m2. Compute the instantaneous magnitude of the magnetic field at the same point and time.itude. Question 12, chap 33, sect 5. part 2 of 5 10 points What is the instantaneous magnitude of the Poynting vector at the same point and time? Question 13, chap 33, sect 5. part 3 of 5 10 points What are the directions of the instantaneous magnetic field and theQuestion 14, chap 33, sect 5. part 4 of 5 10 points What is the instantaneous value of the energy density of the electric field? Question 16, chap 33, sect 6. part 1 of 4 10 points Consider an electromagnetic plane wave with time average intensity 104 W/m2 . The speed of light is 2.99792 × 108 m/s and the permeability of free space is 4 π × 10−7 T・m/A. What is its maximum electric field? What is the instantaneous value of the energy density of the magnetic field? Question 17, chap 33, sect 6. part 2 of 4 10 points What is the the maximum magnetic field? Question 19, chap 33, sect 6. part 4 of 4 10 points Consider an electromagnetic wave pattern as shown in the figure below. Question 18, chap 33, sect 6. part 3 of 4 10 points What is the pressure on a surface which is perpendicular to the beam and is totally reflective? Question 20, chap 33, sect 8. part 1 of 1 10 points A coin is at the bottom of a beaker. The beaker is filled with 1.6 cm of water (n1 = 1.33) covered by 2.1 cm of liquid (n2 = 1.4) floating on the water. How deep does the coin appear to be from the upper surface of the liquid (near the top of the beaker)? An cylindrical opaque drinking glass has a diameter 3 cm and height h, as shown in the figure. An observer’s eye is placed as shown (the observer is just barely looking over the rim of the glass). When empty, the observer can just barely see the edge of the bottom of the glass. When filled to the brim with a transparent liquid, the observer can just barely see the center of the bottom of the glass. The liquid in the drinking glass has an index of refraction of 1.4 . θi h d θr eye Calculate the angle θr . Question 22, chap 33, sect 8. part 2 of 2 10 points Calculate the height h of the glass.