Seeing is Believing A lesson about Microscopes By Sarah O’Rourke, Fairfield Middle School & M. Kathleen Stansbury, Tuckahoe Middle School

What in the world is that?

What in the world is that???

See how many pictures you can guess correctly on your Tic-Tac-Toe!

Tools in Science

Microscope Invented Hans & Zacharias Janssen o Invented the first simple microscope o Later, he made the 1 st compound microscope (2 lenses) o Allowed people to see things never before seen!

Robert Hooke 1655 Used microscope to look at oak cork He observed “tiny little boxes” Called structures “cells ”

Review Who named cells because they looked like “tiny boxes”? a.Francesco Redi b.Louis Pasteur c.Robert Hooke d.Albert Einstein

Anton Van Leeuwenhoek 1675 Used a simple microscope (1 lens): o Observed blood, rainwater, sperm etc. Called them “ animalcules ” because they looked like little animals

Matthias Schleiden 1838 German botanist Discovered that plants are also made of cells!

Theodor Schwann 1850 German zoologist Viewed animal parts under microscope Discovered animals were made of cells

Rudolph Virchow 1858 German Doctor Concluded that all living cells come only from other living cells

Review Who was the first person to observe living cells? (He called them animalcules) a.Robert Hooke b.Francesco Redi c.Anton van Leeuwenhoek d.Rudolph Virchow

Cool Jobs In Science Molecular Biology

Why is it Important? The microscope allowed scientist to observe things that could not be seen with the naked eye o Cells for example! Makes things appear larger than they really are!

Your Design Task Research/Background Click picture… Problem You are a field biologist. In order to find the most extraordinary specimens, you need to go into extreme environments. On your latest adventure, you forgot your field microscope. Create a microscope that is portable and can be used in these environments.

Your Design Task Materials: Building materials from recycle bin o cardboard tubes o plastic bottles Card stock/ index cards Construction paper Magnifying lenses Small flashlight such as a finger light Tools Markers Scissors Tape Ruler

Your Design Task Constraints/ Restrictions/ Rules: Must be in a team of 2 You have 30 minutes to design/build Complete your design sketch before you get materials Your microscope must fit in a shoe box and survive a durability “Shake Test” Goal Design a portable and durable microscope that magnifies a specimen.

How does it Work? Microscopes use glass lenses to bend light This makes things appear larger or smaller depending on the shape of the lens Compound microscopes : have more than one lens! o This means they can magnify things even more!

Parts of a Microscope

Function of Parts Body Tube: separates eyepiece from objective lens Eyepiece: contains lens that magnifies 10X Nosepiece: holds objectives lenses and allows rotation

Function of Parts Objective lens (High Power): Magnifies 40X Objective lens (Low Power): Magnifies 10X Coarse Adjustment Knob: moves body tube to focus with low-power objective lens Fine Adjustment Knob: moves body tube to focus with high-power objective lens

Function of Parts Arm: supports the body tube Base: supports the microscope Stage: supports the slide being used Stage clip: holds the slide in place

Function of Parts Diaphragm: controls the amount of light that comes through the stage Mirror/Light Source: reflects light upward through diaphragm

Comparing Powers of Magnification We can see better details with higher the powers of magnification, but we cannot see as much of the image. Which of these images would be viewed at a higher power of magnification?

What’s my power? To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective. What are the powers of magnification for each of the objectives we have on our microscopes?

Calculating Magnification To find the total magnification of a compound microscope you must multiply the magnifying power of both lenses! Example: Ocular Lens (Eye Piece)= 10X magnification Objective Lens = 50X magnification Total magnification = 10 X 50 = 500X

Practice Ocular Lens is 10x & Objective lens is 7x Total Magnification? 10 X 7 = 70x Ocular Lens is 4x & Objective lens is 10x Total Magnification? 4 X 10 = 40x

Try out a real microscope! Getting Into Focus Focusing your microscope Make sure the light switch is turned on. Place a slide onto the stage & secure it using the stage clips Turn the nose piece until the smallest objective lens clicks into place Start by turning the coarse adjustment knob slowly until you begin to see the squares of the fabric through the eye piece. Do NOT touch this know again once it is in focus! Next turn the fine adjustment knob slowly until the objects appear very clear. Repeat these steps for the remaining two objective lenses (medium and high). Cells under the Microscope Label what you are observing Calculate the total magnification by multiplying the eyepiece & the objective lens Follow the directions above to get your specimen into focus

Microscopes Today

Electron Microscopes Today scientists can use electron microscopes to look inside cells! These microscopes use electrons instead of light to magnify object even more! o Same particles that light up your television!

Scanning Electron Microscope Transmission Electron Microscope The scanning electron microscope (SEM) uses a focused beam of high-energy electrons to generate images of the surface of a solid specimen. A technique where a beam of electrons is transmitted through an ultra-thin specimen. An image is formed from the interaction of the electrons transmitted through the specimen. the image is magnified and focused onto an imaging device or on a layer of photographic film.

Recent Discovery in Microscopy The foot is covered by tiny hairs that spilt off into smaller and smaller hairs. Because these hairs are so small, it creates a molecular forces that allows the Gecko to be able to stick to surfaces with out glue !