Microscopes

Biology Index

Where are we going with this? The information on this page introduces microscopes and their use.

Article includes ideas, images, and content from Troy Smigielski (2021-08)

Microscopes

(We should take a very close look at this! See what I did there?)

A microscope is… Okay, most people know what they are and that they allow us to look at very minute details. 

Microscopes are tools that make an enlarged image of something that is otherwise too small to see.

Microscopes differ. Not all are equal.

Microscopes have two important specifications

• Magnification - the power to increase an object’s size
• Resolution - the power to show details clearly

These specifications make a big difference! It's not easy to have BOTH high magnification and high resolution. But, ideally, a good, quality microscope will have strong magnification and high resolution.

Source

Microscopes have been around for a long time. A dude named Zacharias Janssen is credited with inventing the microscope. Later, Anton van Leeuwenhoek was acknowledged as being the first microscopist. 

Later still, Robert Hooke discovered and coined the term "cell" by using a microscope to examine cork.

Microscopic Cork Image

Types of Microscopes

There are three types of microscopes! Yeah, that's right! Three!

Compound Light Microscopes

The compound light microscope is the most common type. 

• Uses a mirror (or other light source) that directs light upward through the specimen and into the lenses.

• Specimens can be living or non-living

• Can magnify up to 1000x.

About the Compound Light Microscope…

 

The compound light microscopes has an ocular lens (the one your eye goes on) and 4 objective lenses (the ones that point at the object you are trying to see).

•  The ocular lens is always 10x.

• You only use one of the 4 objective lenses at a time. The objective lenses have different powers such as:

• Scanning lens = 4x 

 

• Low objective = 10x 

 

• High objective = 40x 

 

• Oil immersion = 100x

The total magnification is equal to the power of the ocular lens multiplied by the objective lens.

As you magnify the image, you see less and less of it (duh). What you can see is called the field of view.

Said differently, the field of view is the diameter of the what you can see. The field of view decreases as magnification increases. 

Parts of a compound light microscope…

1. Body tube

2. Revolving nosepiece

3, 4, 5. Objective lenses

6. Stage clips

7. Diaphragm

8. Light source

9. Ocular lens (Eyepiece)

10. Arm

11. Stage

12. Course focus adjustment knob

13. Fine focus adjustment knob

14. Base

Scanning Electron Microscope (SEM)

• Uses a stream of electrons (not light) to produce an image.

• Specimens are non-living

• Can magnify up to 100,000 x

• Creates a 3-dimensional image

Transmission Electron Microscope (TEM)

• Uses a beam of electrons (not light) to produce an image

• Specimens are non-living

• Can magnify up to 200,000 x

• Looks at interior of cells

What is Physics?

Physics Index

Where are we going with this? The information on this page introduces the broad topic of physics by identifying different fields within it.

What is Physics?

(Yeah, some of us need to start with this!)

Physics enjoys, within broader pop culture, the respect of being a brainy, high-level, impressive knowledge. That's nice. But… physics really can be accessible to anyone, and in fact, it is commonly used on a daily basis by a huge sector of society. Actually, anyone operating a machine or crossing a bridge, or sitting on furniture is relying on physics.

Physics need not be impossibly difficult. It's not like it's rocket science! 

Wait! Actually, rocket science is physics!

Physics is the study of matter, energy, and time… and how those three things react and interact.

Modeling Reality

Taking a broad look at it, the purpose of physics is to create models (often involving math) that attempt to reliably explain the basic features of complex phenomena.

These models only describe a part of realty, but they help build hypotheses and help guide experimental design.

The Broad Scope of Physics

Physics includes many things: mechanics, heat, light and other radiation, sound, electricity, magnetism, the structure of atoms, outer space… and more! 

There are a number of common ways that physics topics are grouped. For instance…

Mechanics: the study of forces and motions; motion and its causes; interactions between moving and non-moving objects.

Examples:

Moving objects

Falling objects

Friction

Weight

Spinning objects

Bridges

Fluid Mechanics: the study of mechanics related to liquids, gases, and plasmas and the forces on them.

Examples:

Hydraulic jacks

Piping

Boats

Hot-air balloons and blimps

Thermodynamics: the study of heat and its effect on matter including temperature, pressure, volume and heat transfer.

Examples:

Melting

Freezing

Engines

Refrigerators

Heat transfer

Vibrations and Waves: the study of mechanical waves through physical media

Examples:

Ocean waves

Earthquakes

Sound

Periodic Motion: the study of the motion that repeats in equal intervals of time.

Examples:

Pendulums

Springs

Optics: the study of the behavior and properties of light and its interaction with matter

Examples:

Mirrors

Lenses

Color

Cameras

Electromagnetism: the study of electricity and magnetism and the resulting fields of force; the radiation of electromagnetic energy.

Examples:

Radio signals

Xray

Cell phone signals

Relativity: a model or construct to explain observed phenomena, general and special relativity examines the universe, especially with regard to objects or particles moving at high rates of speed or where gravitational forces are extreme,

Examples:

Particle collisions

Particle accelerators

Atomic Physics: the study of atoms with regard to electrons and atomic nuclei.

Examples:

Electron configuration

Plasmas

Nuclear Physics: the study of atomic nuclei and their interactions.

 

Examples:

Fission

Fusion

Radioactive decay

Quantum Mechanics: describes (models) the physical properties of nature at the scale of atoms and subatomic particles.

Examples:

Atoms

Parts of atoms

Astrophysics: the study of the universe, galaxies, solar systems, planets and moons.\

Examples

Astronomy

Much of physics rubs up against or even overlaps with topics of chemistry, so you might see some things that seem familiar. However, the two subjects are subtly differentiated.

The Goal of Physics (reprised)

The goal of physics is to describe the physical world in terms of how matter and energy interact. The laws of physics grow out of basic concepts, assumptions, established relationships and equations that can predict how things behave.

How does that actually work?

Think of physics like this…

For any known relationship between objects, energy, and time, the laws of physics serve as a "because," so whatever conditions are present act like an "if" and the predicted outcome is the "then" such that…

Because [some relationship exists], if [some conditions are present] then [some outcome will occur].

Let's try it this way…

Because the distance an object will travel can be found using the equation

d = vt

(where d is the distance, v is velocity (rate of motion), and t is the elapsed time),

if a car travels at 20 m/hr for 3 hours

then it will have moved a distance of 60 miles.

The outcome (the then) of any situation (the if) will be determined by relevant laws of physics (the because).

Tennessee Standard Physics Standards

 The following information comes from

https://www.tn.gov/content/dam/tn/stateboardofeducation/documents/massivemeetingsfolder/meetingfiles4/10-20-17_III_J_Non-Substantive_Changes_to_Math_ELA__Science_Standards_Attachment_3_-_Science.pdf (2020/07/19)

beginning on page 116 and following…

PHYSICS: COURSE OVERVIEW

The Physics academic standards were written to establish the core content and practices for all schools in the state of Tennessee. The core and component ideas in the Physical Sciences section in A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ides were used to subdivide the Physics course content into four sections:

Physics (PHYS)

Physical Sciences (PS)

Matter and Its Interactions

• Structure and properties of matter

• Chemical reactions

• Nuclear process

Motion and Stability: Forces and Interactions

• Forces and motion

• Types of interactions

• Stability and instability in physical

  systems

Energy

• Definitions of energy

• Conservation of energy and energy

  transfer

• Relationship between energy and

  forces

• Energy in chemical processes and

  everyday life

Waves and Their Applications in Technologies for Information Transfer

• Wave properties

• Electromagnetic radiation

• Information technologies and

  instrumentation

PS1: Matter and Its Interactions

Properties of matter give rise to fields and forces. Students should understand that there are only a few properties of matter at a fundamental level and that these properties (charge, mass, spin) give rise to the fields and forces that exist as we understand them.

PS2: Motion and Stability: Forces and Interactions

An understanding of the forces and interactions between objects is important for describing an object’s motion and determining the stability in a system. Students should understand that forces between objects arise from four types of interactions (gravitational, electromagnetism, and strong and weak nuclear interactions) and that some physical systems are more stable than others.

PS3: Energy

The concept of the transfer of energy in or out of a system can be explained and predicted. Students should understand the conservation of energy, how it is stored and transferred, the relationship between forces and how they are related to energy, and how we use energy in our everyday life.

PS4: Waves and Their Applications in Technologies for Information Transfer

Optics is the study of the interaction of optical photons (within the human visible range) with matter. These standards encompass the speed of light in a vacuum and other media, as well as diffraction, refraction, and the interference properties of light.

Throughout the Physics course, the seven crosscutting concepts should be reinforced in the appropriate context both in the classroom and hands-on experimentation. These standards also incorporate the core and component ideas in engineering, technology, and applications of science (cited throughout the standards) and should be implemented in this course.

Science and engineering practices are used as a means to learn science by doing science, thus combining content knowledge with skill.

By combining content knowledge with skill, students discover how scientific knowledge is acquired and applied to solve problems or advance scientific knowledge further. In addition, there are seven crosscutting concepts that are and crosscutting concepts, within each core idea to provide students with a well-rounded education in science.

These standards were written to allow students to engage in scientific reasoning, critique, creative thinking, and applied learning through hands-on investigations.

These academic standards should be used in order to develop classroom and course-level assessments. Although science is a body of content knowledge consisting of theories that explain data, science is also a set of practices that use analysis and argumentation to establish, extend, and refine knowledge. The These practices are not intended to be a sequence of steps nor are they intended to be taught as a separate, introductory unit for the course.

Fundamental to the nature of science and thus stretch across all science disciplines. The Physics standards have been constructed by explicitly integrating practices iteratively and in combination,

PHYSICS: ACADEMIC STANDARDS

PHYS.PS1: Matter and Its Interactions

1) Develop models to illustrate the changes in the composition of the nucleus of an atom and the energy released during the processes of fission, fusion, and radioactive decay.

2) Recognize and communicate examples from everyday life that use radioactive decay processes.

3) Investigate and evaluate the expression for calculating the percentage of a remaining atom (N(t)=N0e-λt) using simulated models, calculations, and/or graphical representations. Define the half- life (t1/2) and decay constant λ. Perform an investigation on probability and calculate half-life from acquired data (does not require use of actual radioactive samples).

PHYS.PS2: Motion and Stability: Forces and Interactions

1) Investigate and evaluate the graphical and mathematical relationship (using either manual graphing or computers) of one-dimensional kinematic parameters (distance, displacement, speed, velocity, acceleration) with respect to an object's position, direction of motion, and time.

2) Algebraically solve problems involving constant velocity and constant acceleration in one-dimension.

3) Algebraically solve problems involving arc length, angular velocity, and angular acceleration. Relate quantities to tangential magnitudes of translational motion.

4) Use free-body diagrams to illustrate the contact and non-contact forces acting on an object. Use the diagrams in combination with graphical or component-based vector analysis and with Newton's first and second laws to predict the position of the object on which the forces act in a constant net force scenario.

5) Gather evidence to defend the claim of Newton's first law of motion by explaining the effect that balanced forces have upon objects that are stationary or are moving at constant velocity.

6) Using experimental evidence and investigations, determine that Newton’s second law of motion defines force as a change in momentum, F = Δp/Δt.

7) Plan, conduct, and analyze the results of a controlled investigation to explore the validity of Newton's second law of motion in a system subject to a net unbalanced force, Fnet = ma or Fnet = Δp/Δt.

8) Use examples of forces between pairs of objects involving gravitation, electrostatic, friction, and normal forces to explain Newton's third law.

9) Use Newton’s law of universal gravitation, 𝑭𝑭 = 𝐺𝐺 𝑚𝑚1𝑚𝑚2, to calculate the gravitational forces, mass, 𝒓𝒓2  or distance separating two objects with mass, given the information about the other quantities.

10) Describe and mathematically determine the electrostatic interaction between electrically charged particles using Coulomb’s law, 𝑭𝑭 = 𝑘𝑘 𝑞𝑞𝒓𝒓𝑞𝑞 . Compare and contrast Coulomb’s law and gravitational 𝒆𝒆 𝑒𝑒122 force, notably with respect to distance.

11) Develop and apply the impulse-momentum theorem along with scientific and engineering ideas to design, evaluate, and refine a device that minimizes the force on an object during a collision (e.g., helmet, seatbelt, parachute).

12) Use experimental evidence to demonstrate that air resistance is a velocity dependent drag force that leads to terminal velocity.

13) Develop a model to predict the range of a two-dimensional projectile based upon its starting height, initial velocity, and angle at which it was launched.

14) Plan and conduct an investigation to provide evidence that a constant force perpendicular to an object's motion is required for uniform circular motion (F = m v2 / r).

PHYS.PS3: Energy

1) Identify and calculate different types of energy and their transformations (thermal, kinetic, potential, including magnetic and electrical potential energies) from one form to another in a system.

2) Investigate conduction, convection, and radiation as a mechanism for the transfer of thermal energy.

3) Use the principle of energy conservation and mathematical representations to quantify the change in energy of one component of a system when the energy that flows in and out of the system and the change in energy of the other components is known.

4) Assess the validity of the law of conservation of linear momentum (p=mv) by planning and constructing a controlled scientific investigation involving two objects moving in one-dimension.

5) Construct an argument based on qualitative and quantitative evidence that relates the change in temperature of a substance to its mass and heat energy added or removed from a system.

6) Define power and solve problems involving the rate of energy production or consumption (P = ΔE/Δt). Explain and predict changes in power consumption based on changes in energy demand or elapsed time. Investigate power consumption and power production systems in common use.

7) Investigate and evaluate the laws of thermodynamics and use them to describe internal energy, heat, and work.

8) Communicate scientific ideas to describe how forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space. Explain how energy is contained within the field and how the energy changes when the objects generating and interacting with the field change their relative positions.

9) Describe, compare, and diagrammatically represent both electric and magnetic fields. Qualitatively predict the motion of a charged particle in each type of field, but avoid situations where the two types of fields are combined in the same region of space. Restrict magnetic fields to those that are parallel or perpendicular to the path of a charged particle.

10) Develop a model (sketch, CAD drawing, etc.) of a resistor circuit or capacitor circuit and use it to illustrate the behavior of electrons, electrical charge, and energy transfer.

11) Investigate Ohm’s law (I=V/R) by conducting an experiment to determine the relationships between current and voltage, current and resistance, and voltage and resistance.

12) Apply the law of conservation of energy and charge to assess the validity of Kirchhoff’s loop and junction rules when algebraically solving problems involving multi-loop circuits.

13) Predict the energy stored by a capacitor and how charge flows among capacitors connected in series or parallel.

14) Recognize and communicate information about energy efficiency and/or inefficiency of machines used in everyday life.

15) Compare and contrast the process, design, and performance of numerous next-generation energy sources (hydropower, wind power, solar power, geothermal power, biomass power, etc.).

PHYS.PS4: Waves and Their Applications in Technologies for Information Transfer

1) Know wave parameters (i.e., velocity, period, amplitude, frequency, angular frequency) as well as how these quantities are defined in the cases of longitudinal and transverse waves.

2) Describe parameters of a medium that affect the propagation of a sound wave through it.

3) Understand that the reflection, refraction, and transmission of waves at an interface between two media can be modeled on the basis of characteristics of specific wave parameters and parameters of the medium.

4) Communicate scientific and technical information about how the principle of superposition explains the resonance and harmonic phenomena in air columns and on strings and common sound devices.

5) Evaluate the characteristics of the electromagnetic spectrum by communicating the similarities and differences among the different bands. Research and determine methods and devices used to measure these characteristics.

6) Plan and conduct controlled scientific investigations to construct explanations of light's behavior (reflection, refraction, transmission, interference) including the use of ray diagrams.

7) Evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described either by a wave model or a particle model.

8) Obtain information to construct explanations on how waves are used to produce, transmit, and capture signals and store and interpret information.

9) Investigate how information is carried in optical systems and use Snell’s law to describe the properties of optical fibers. 

Additionally…

Crosscutting Concepts

These are concepts that permeate all science and show an interdependent connection among the sciences differentiated from grades K-12. Tennessee state science standards have explicitly designed the standard progression to include these crosscutting concepts:

• Pattern observation and explanation

• Cause and effect relationships that can be explained through a mechanism

• Scale, proportion, and quantity that integrate measurement and precision of language

• Systems and system models with defined boundaries that can be investigated and characterized by the next three concepts

• Energy and matter conservation through transformations that flow or cycle into, out of, or within a system

• Structure and function of systems and their parts

• Stability and change of systems

Science and Engineering Practices

The science and engineering practices are used as a means to learn science by doing science, thus combining knowledge with skill. The goal is to allow students to discover how scientific knowledge is produced and how engineering solutions are developed. The following practices should not be taught in isolation or as a separate unit, but rather differentiated at each grade level from K-12 and integrated into all core ideas employed throughout the school year. These are not to be taught in isolation but are embedded throughout the language of the standards.

• Asking questions (for science) and defining problems (for engineering) to determine what is known, what has yet to be satisfactorily explained, and what problems need to be solved.

• Developing and using models to develop explanations for phenomena, to go beyond the observable and make predictions or to test designs.

• Planning and carrying out controlled investigations to collect data that is used to test existing theories and explanations, revise and develop new theories and explanations, or assess the effectiveness, efficiency, and durability of designs under various conditions.

• Analyzing and interpreting data with appropriate data presentation (graph, table, statistics, etc.), identifying sources of error and the degree of certainty. Data analysis is used to derive  meaning or evaluate solutions.

• Using mathematics and computational thinking as tools to represent variables and their relationships in models, simulations, and data analysis in order to make and test predictions.

• Constructing explanations and designing solutions to explain phenomena or solve problems.

• Engaging in argument from evidence to identify strengths and weaknesses in a line of reasoning, to identify best explanations, to resolve problems, and to identify best solutions.

• Obtaining, evaluating, and communicating information from scientific texts in order to derive meaning, evaluate validity, and integrate information. 

What is Science?

Intro to Chemistry and Physics Index

Biology Index
General Chemistry Index

Physics Index

Where are we going with this? The information on this page is foundational to science and scientific inquiry. 

What is Science?

(Well, that seems like a pretty good place to start!)

Let's be honest… Back in elementary school everyone loved science! The hamsters! Fire! Terrariums! Yeah! that was cool!

Source: Click Here

Somewhere along the way, something happened. Good ol' science got infected with numbers. And measuring stuff. And… well… just like students, with the passing of time, science become more complicated. As we got older and able to do more with our brains, the study of science became more specific and focused.

What happened?

As we grew up, our utilization of science grew to include more and more of what science is, and what it is intended to do.

The goal of science is to investigate and understand the natural world using previous results to make useful predictions.

The more mature we are, the more complicated those investigations are!

(That sort of spoils that whole hamster thing. Also, why is there no "p" in hamster?)

Unpacking the above goal of science, there are a few things to consider. The first part of the definition calls attention to the investigation process, the goal of which is understanding… understanding with the intention of—with the goal of—using what is learned in the previous results to make useful predictions about how things might behave in future, similar situations.

 So, what is science? Let's go with this:

Science is… 

• a system of knowledge about the natural world and the methods used to find that knowledge. 

• the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment. 

When something is discovered, it lays the groundwork for future discoveries. Science is a progressive way of using evidence to learn about the natural world, and it builds on previous findings. And on previous failures to find things, for that matter!

Since science builds and grows on previous efforts, it seems reasonable that some sort of systematic approach to scientific inquiry would exist. Yeah… it does… 

And it has a name! Check it out!  Scientific Method 

___________________

Contributions from Troy Smigielski