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BOMB: The Race to Build-and Steal- the World’s Most Dangerous Weapon Nonfiction Book Study: Lab: Heavy Water

This book study provides curated information and guided reading and assignments for the book BOMB by Steve Sheinkin

Essential Question

How did the contributions of physicists in the making of the atomic bomb affect the world as we know it?

Lab Directions

We will use marshmallows and toothpicks to build models of “ordinary” water and heavy water.
Large marshmallows represent the oxygen atoms.
Mini marshmallows represent the protons and neutrons needed to build hydrogen atoms.
Protons will be purple.

Neutrons will be pink.

1. On two large marshmallows (oxygen atom) color 8 purple dots to represent oxygens 8 protons. Then, color 8 pink dots to represent the 8 neutrons of the most common isotope of oxygen. (refer to picture of oxygen form the periodic table)

2. Color 4 mini marshmallows purple.

3. Color 2 mini marshmallow pink.

4. Start with ordinary water. “ordinary” hydrogen consists of one proton and no neutrons. (refer to picture of hydrogen form periodic table)

5. Take 2 toothpicks and attach a single proton to each one. Then attach each toothpick to one oxygen marshmallow. This represents “ordinary” water.

6. Next make heavy water. Deuterium is an isotope of hydrogen that has one neutron. Make two Deuterium atoms by taking two toothpicks and attaching one proton and one neutron marshmallow to each toothpick. Then attach both toothpicks to an oxygen marshmallow. This represents heavy water.

7. Make some observations about the differences. Be prepared to be called to discuss your observations.

8. Proceed to the handout (see adjacent box)

Heavy Water

Student Expectations

We will conduct a lab to demonstrate the difference between ordinary water and heavy water.

I will record my observations by comparing/contrasting ordinary water to heavy water. 

Activity: Lab- Heavy Water


“Ordinary” Water

Heavy Water

Color-coded model drawing



# of H




Mass of H




# of O




Mass of O




Molecular mass




Total number of neutrons



Total number of protons




1. What is the mass of a common hydrogen atom?
2. What is the mass of one molecule of heavy water?
3. What is the mass of a hydrogen in a heavy water molecule?
4.What is the mass of one molecule of “ordinary” water?
5. Why is it called “Heavy Water”?