Limiting Factors

Limiting Factors

Middle School

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Learning Objectives

• Identify at least five different career paths in the field of chemistry.

• Describe the important contributions of scientists Gertrude Elion, Donna Nelson, and James A. Harris.

• Explain how technologies like the cyclotron and scanning tunneling microscope help in scientific discoveries.

• Understand the process of creating new elements and adding them to the periodic table.

Key Vocabulary

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Biochemist

An expert who explores the molecules that support life, such as DNA and other important proteins.

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Chemical Engineer

A professional who solves problems with producing and using substances, like purifying water or processing food.

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Organic Chemist

A scientist who focuses on the carbon-based substances found in living things and their reactions.

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Nanoscience

The study and manipulation of matter and chemical changes on an extremely small, or nano, scale.

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Cyclotron

A device that uses electricity to accelerate atomic particles to create new elements.

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6-mercaptopurine (6-MP)

A molecule created by Gertrude Elion that helps the human immune system fight cancers like leukemia.

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Diverse Careers in Chemistry

Applied Chemistry

• ​Pharmacologists study how different chemicals and drugs affect the body to develop new medicines.

• ​​Forensic scientists use their knowledge of chemistry to analyze evidence and help solve crimes.

• ​Biochemists analyze samples of body tissue to help develop antibiotics and other treatments.

Fundamental Science

• ​Environmental chemists study the effect of chemicals on the natural world, like in rivers.

• ​​Materials scientists work to develop new materials that are lighter and much stronger.

• ​Organic chemists focus on carbon-based molecules, which are the building blocks of all life.

Multiple Choice

What common principle connects the work of a pharmacologist, a materials scientist, and an environmental chemist?

• They all apply the principles of chemistry to their work.

• They all focus on creating new medicines for diseases.

• They all work to solve crimes using evidence.

• They all study carbon-based molecules found in living things.

Multiple Choice

How does the work of a pharmacologist in 'Applied Chemistry' differ from the work of an organic chemist in 'Fundamental Science'?

• A pharmacologist works to develop new medicines, while an organic chemist studies the basic building blocks of life.

• A pharmacologist analyzes crime scene evidence, while an organic chemist studies river pollution.

• A pharmacologist develops new strong materials, while an organic chemist analyzes body tissues.

• A pharmacologist studies carbon-based molecules, while an organic chemist studies how drugs affect the body.

Multiple Choice

A scientist is analyzing a sample of river water to measure pollution and also analyzing a tissue sample to help develop an antibiotic. Which two fields is this scientist working in?

• An environmental chemist and a biochemist.

• A forensic scientist and a materials scientist.

• An organic chemist and a pharmacologist.

• A materials scientist and a forensic scientist.

Multiple Choice

Investigators at a crime scene find a fragment of a unique, lightweight, and super-strong synthetic fabric. Which two specialists would most likely be needed to analyze this evidence and help solve the crime?

• A forensic scientist and a materials scientist.

• A pharmacologist and an environmental chemist.

• A biochemist and an organic chemist.

• An environmental chemist and a forensic scientist.

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Pioneers in Chemistry: Nelson & Elion

Donna Nelson

• An organic chemist who studies how modifying a molecule affects the speed of a chemical reaction.

• Her nanoscience research provides information to engineers developing products like soap and medicine.

• She is a strong advocate for science education and diversity in STEM fields.

Gertrude B. Elion

• A biochemist who pioneered a new way to discover drugs by designing specific molecules.

• Her work aimed to block the growth of unwanted cells, like those causing cancer.

• She discovered 6-mercaptopurine, a molecule that helps fight leukemia in children.

Multiple Choice

What is the primary area of scientific contribution for both Donna Nelson and Gertrude B. Elion?

• Chemistry

• Engineering

• Science education

• Nanoscience

Multiple Choice

What is a key difference in the research focus of Donna Nelson and Gertrude B. Elion?

• Nelson studies how to change reaction speeds, while Elion focused on designing molecules to stop cell growth.

• Nelson develops new medicines, while Elion works on creating better soaps.

• Nelson is a biochemist, while Elion is an organic chemist.

• Nelson advocates for diversity in STEM, while Elion discovered a cure for leukemia.

Multiple Choice

A team of engineers is trying to develop a new, more effective laundry detergent that works faster in cold water. Which scientist's research would be most directly applicable to this problem?

• Donna Nelson's work on how modifying molecules affects reaction speeds.

• Gertrude B. Elion's work on designing molecules to block cell growth.

• Donna Nelson's advocacy for diversity in science education.

• Gertrude B. Elion's discovery of a drug to fight leukemia.

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Visualizing the Atomic World

• Ernest Rutherford discovered the atom's structure: a positive nucleus and orbiting electrons.

• Scientists then predicted that atoms in solids form well-ordered, repeating patterns.

• For decades, this remained a theory as atoms were too small to see.

• In 1981, the STM microscope finally allowed scientists to see these arrays.

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Multiple Choice

According to Ernest Rutherford's model, what is the basic structure of an atom?

• A positive nucleus with orbiting electrons.

• A solid sphere with no internal parts.

• A negative nucleus with orbiting protons.

• A random collection of charged particles.

Multiple Choice

For many decades, why was the idea that atoms in solids form repeating patterns considered only a theory?

• The patterns were thought to be too complex to be real.

• Scientists believed atoms were constantly in random motion.

• The theory was proposed by an unpopular scientist.

• Scientists did not have tools powerful enough to see atoms.

Multiple Choice

What conclusion can be drawn about the impact of the STM microscope?

• It allowed scientists to discover the existence of the atom for the first time.

• It proved that atoms were much larger than previously thought.

• It provided the first direct evidence to confirm that atoms in solids are arranged in orderly patterns.

• It helped Ernest Rutherford develop his initial model of the atom.

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How Are New Elements Made?

• By 1940, scientists knew adding a proton to uranium creates a new element.

• Ernest O. Lawrence invented the cyclotron, a machine that speeds up tiny particles.

• The cyclotron crashes these fast particles into the nucleus of a heavy element.

• This method was used to create radioactive elements 93 through 106.

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Multiple Choice

What is the fundamental way to create a new element?

• By changing the number of protons in an atom's nucleus.

• By making an element radioactive.

• By speeding up the particles within an element.

• By crashing two heavy elements into each other.

Multiple Choice

What role does a cyclotron play in creating new elements?

• It makes heavy elements radioactive.

• It holds the new element after it is created.

• It accelerates tiny particles to high speeds.

• It discovers which elements are heaviest.

Multiple Choice

Which statement best explains why a machine like the cyclotron is necessary to create new, heavy elements?

• The cyclotron is the only machine that can handle radioactive materials.

• The cyclotron provides the force needed for a particle to combine with a heavy nucleus.

• Speeding up particles is the only way to create elements heavier than uranium.

• Ernest O. Lawrence discovered elements 93 through 106 with the machine.

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A Leader in Nuclear Chemistry: James A. Harris

• James A. Harris was the first African American to help discover new elements.

• In 1969, his team discovered elements 104 (Rutherfordium) and 105 (Dubnium).

• He led the production of special targets used for creating the new elements.

• Harris inspired young minority students to pursue careers in science and engineering.

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Multiple Choice

What was a major scientific contribution of James A. Harris?

• He was the first African American to co-discover new chemical elements.

• He invented a new type of microscope for studying atoms.

• He was the lead scientist who named elements 104 and 105.

• He wrote the first textbook on nuclear chemistry.

Multiple Choice

What was the relationship between James A. Harris's work and the discovery of new elements?

• He was in charge of creating the specific materials needed for the discovery experiments.

• He was responsible for analyzing the data after the experiments were done.

• He designed the laboratory where the discoveries took place.

• He funded the research that led to the discoveries.

Multiple Choice

Which statement best explains the overall importance of James A. Harris's career?

• He was a trailblazer who made significant scientific discoveries and inspired future generations of minority scientists.

• His work was only important because it led to the discovery of two specific elements.

• He was mainly known for his ability to manage a team of scientists.

• His most important contribution was encouraging students to study engineering.

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Common Misconceptions

Misconception	Correction
A scientist must have a specific background, gender, or race.	Scientists come from all backgrounds, genders, and races.
All elements on the periodic table are found in nature.	Only 90 elements are natural; the rest are created in labs.
You need a doctorate to make major scientific discoveries.	Hard work and innovation, not just degrees, lead to major discoveries.

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Summary

• Chemistry offers diverse careers in medicine, materials science, and environmental protection.

• Pioneering scientists like Nelson, Elion, and Harris made world-changing discoveries.

• New technologies are crucial for scientific advancements like discovering new elements.

• The periodic table includes natural and synthetic elements, which can be unstable.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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