(Wikimedia Commons – author Fastfission)
Thomson’s plum pudding model

Structure of the Atom (using some sheltered instruction techniques)
Topic: Structure of the
Atom
Class: Physical Science Date:
Content Objective: sheltered technique.)
Students will be able to compare the properties of the proton, neutron, and electron. (Post this on the board as a
Language Objective:
Acquire and use accurately grade-appropriate general academic and domain-specific words and phrases; gather vocabulary knowledge when considering a word or phrase important to comprehension or expression.
.
Key Vocabulary : proton, neutron, electron, atom, element, nucleus (Limiting key vocabulary to five per day is a sheltered technique…yes, I see that there are six words.)
Essential Question:
How are protons, neutrons, and electrons different from each other? Are there any ways in which they are similar to each other?
Language Objectives: (Stated in Student Friendly
Language): When talking with lab/activity partners, use the key vocabulary words appropriately.
Materials (including Supplementary and
Adapted ) : three pieces of light colored copy paper per student (three different colors), tape or glue, scissors, stapler, directions, map of Europe, diagram of plum pudding model, textbook (if possible), container of snack pack vanilla pudding, box of raisins
Higher-Order Questions:
If you wanted to find out more information about protons, neutrons, and electrons, where would you look?
How did scientists discover the existence of protons, neutrons, and electrons?
What else was happening in the world when these discoveries were being made?
We are using a foldable to compare the properties of the proton, neutron, and electron. Can you think of a different way to compare them?
How do you think I am going to use the snack pack to teach you about atoms?
(Using higher order questions is a sheltered technique.)
JJ Thomson called his model of the atom “The plum pudding model.” These days in the United States, this does not help people understand what he meant.
Create a modern name for this model that would help others understand.
Lesson Sequence
Warm up: How will you get students interested in the topic?
“I wonder if any of you have heard of atoms. I would like you to form groups of three or four and write down three things that you already know about atoms.” Give students a few minutes to

talk together and have them report back. (Building on background knowledge is a sheltered technique.)
Anticipatory Set (Building Background) : How will you build/activate background knowledge?
Tell the story of Democ ritus (460-360 BC )and how he coined the term “atom”.
He was the first person to come up with the idea that at some point, matter cannot be divided into smaller quantities. Although scientists have modified his ideas over time, the atom is the smallest unit of an element that still maintains the properties of that element. Show a map of
Europe and ask if any of the students can show where Greece is on the map. Explain that
Democritus grew up in Greece. You might also ask if the students know any of the other countries on the map. (Activating background knowledge is a sheltered technique.)
Lesson Focus (Teacher Modeling) :
What will you do (step-by-step) to teach to content objective?
1.
As an advance organizer, have students prepare the foldable and add the tabs. This will give them an idea about what to listen for/look for when you lecture or have them read the text. (Read independent practice below and decide how you want to structure it for your class.) (This is a sheltered technique.)
2.
Tell students that Democritus was forgotten for hundreds of years. In the early 1800s,
John Dalton (1766-1844) came up with his own atomic model that was quite similar to the model of Democritus. His idea was that all atoms of the same element are exactly the same. Atoms of different elements are different. Atoms cannot be destroyed. When two of more atoms combine, they form compounds. (John Dalton was from England, have a student find England on the map.) Interesting note…John
Dalton was color blind and wrote so extensively about it that colorblindness was often called “Daltonism.”
3.
Tell about Thomson’s “plum pudding” model.
In 1897, J. J. Thomson (1856-1940
England) did an experiment with a gas. Although the gas did not have a charge, rays made of negative charges were given off. He decided that an atom must be made of negative charges (electrons) that were embedded in a positively charged material. In
England, plum pudding (Christmas pudding) is (or was) a popular dessert and there are raisins, not plums, in it. The raisins represented the negatively charged particles while the pudding represented the positive charge. Think of the nursery rhyme “Little
Jack Horner sat in a corner eating his pudding (or Christmas) pie. He stuck in his thumb and pulled out a plum and said what a good boy am I.” Perhaps not enough kids know the nursery rhyme to bother with it but use it if it would be helpful. This is a good time to pull out a container of Snack Pack Pudding, add some raisins to it, and stir it up (no, the mixture really isn’t anything like Christmas pudding. Also, using realia is a sheltered technique). Point out that the pudding represents the positive charge and the raisins are the negative charge. Since plum pudding is an English dessert, ask students what they would have called it if they had come up with the model. Would it be the chocolate chip atomic model? Have them talk in pairs for a minute to try to come up with a good name or model. (Giving students a chance to talk and process information is a sheltered technique.)
4.
Tell about Rutherford’s experiment
in 1908 (1871-1937 born in New Zealand, worked in Canada and England. Studied with JJ Thomson) Rutherford shot alpha particles at a very thin sheet of gold foil. He expected that the particles would pass

straight through the gold foil and most of them did. A few, however, were deflected and some bounced back. He realized that the mass of the atom was not spread out evenly throughout the atom but instead was concentrated in a very small, positively charged, part of the atom that we now call the nucleus. The results were quite a surprise to Rutherford and to the scientific community. Because of this and other experiments, Rutherford is usually given credit for discovering the proton.
5.
Introduce James Chadwick Although Rutherford suspected the existence of neutrons, James Chadwick(1891-1974 ) conducted experiments in 1932 that illuminated the true nature of neutrons. Neutrons are located in the nucleus with the protons but they do not have an electrical charge. They are almost the same size as protons.
6.
Updates – The nucleus is made of positively charged particles called protons and neutral particles called neutrons. The protons and neutrons are almost the same size but are still tiny and make up a miniscule part of the atom. The electrons are tinier still, about 1/2000 th
the size of a proton or neutron and they travel around the nucleus.
The electrons don’t actually go around in orbits the way most pictures show them but instead they fill up a cloud around the nucleus. The electrons have a negative charge.
Atoms do not usually have a charge and the negative charge of the electron is balanced by the positive charge of the proton.
Guided Practice (Constantly checking for understanding):
How will you practice (step-by-step) the content objective with your students to ensure that everyone understands?
1.
If you have a text available, have students read the text that covers this topic.
2.
In groups of 2-4 have students write one paragraph each about the way each particle was discovered a) electrons b) protons c) neutrons
Independent Practice -
Students will create foldables /flip charts to compare the attributes of protons, neutrons, and electrons. Although each student should create his/her own chart, you may choose to have students work in pairs or small groups. You may also scale up or scale down the difficulty by having students find the information on their own or presenting them with the printed out information and having them put it in the correct place. I prefer to have students write the information by hand on the flip chart even when I provide the information.
1.
Each student gets three pieces of light colored copy paper. Each paper should be a different color. Students stagger the paper and fold it as shown. Staple the papers together to form a flip book with tabs.
2.
Cut the top five pages to form three columns but leave about an inch at the top that is uncut.
3.
Label the top tabs Proton, Neutron, and Electron. Do not write anything else on this flap.
4.
The second tab in each column should be labeled “charge.” Lift the cover page and tell the charge of the particle.
5.
The third tab in each column should be labeled “size.” On this flap, explain the size of this particle.
6.
The fourth tab in each column should be labeled “location.” On this flap, explain the location of this particle. Use the word nucleus as part of your explanation.

7.
The fifth tab in each column should be labeled “diagram.” Draw a picture of an atom and use an arrow to show where this particle is located.
8.
The sixth tab in each column should be labeled “history.” This is the biggest flap and this will be the longest answer. Explain the history of each particle. Who discovered the particle? When? How (if possible)?
Review/Assessment:
Collect and grade the flip books.

In 1897, J. J. Thomson did an experiment with a gas. Although the gas did not have a charge, rays made of negative charges were given off. He decided that an atom must be made of negative charges
(electrons) that were embedded
in a positively charged material.
He discovered electrons.
Rutherford shot alpha particles at a very thin sheet of gold foil. He expected that the particles would pass straight through the gold foil and most of them did. A few, however, were deflected and some
bounced back. He realized that the mass of the atom was not spread out evenly
throughout the atom but instead was concentrated in a very small, positively charged, part of the atom that we now call the nucleus. Because of this and other experiments, Rutherford is usually given credit for discovering the proton.
.
Although Rutherford suspected the existence of neutrons, James Chadwick
(1891-1974 ) conducted experiments in
1932 that illuminated the true nature of neutrons. Neutrons are located in the nucleus with the protons but they do not have an electrical charge

Directions
1.
Each student gets three pieces of light colored copy paper. Each paper should be a different color. Stagger the paper and fold it as shown. Staple the papers together to form a flip book with tabs.
2.
Cut the top five pages to form three columns but leave about an inch at the top that is uncut.
3.
Label the top tabs Proton, Neutron, and Electron. Do not write anything else on this flap.
4.
The second tab in each column should be labeled “charge.” Lift the cover page and tell the charge of the particle. Use a complete sentence.
5.
The third tab in each column should be labeled “size.” On this flap, explain the size of this particle.
6.
The fourth tab in each column should be labeled “location.” On this flap, explain the location of this particle. Use the word nucleus as part of your explanation.
7.
The fifth tab in each column should be labeled “diagram.” Draw a picture of an atom and use an arrow to show where this particle is located.
8.
The sixth tab in each column should be labeled “history.” This is the biggest flap and this will be the longest answer. Explain the history of each particle. Who discovered the particle? When? How (if possible)?