Bobo Explores Light in the Classroom

“This e-book helps to bring another platform of teaching to science education.”
-Valerie, elementary school teacher

We’ve been delighted to hear from teachers who have incorporated Bobo Explores Light into their science and reading classroom activities. In creating the app, our team was driven by a passion for teaching and a deep admiration for teachers who bring creativity and joy to their work. To that end, we’re collecting some of the more interesting and creative ideas for using Bobo Explores Light in the classroom. The first set is posted below, but please check back occasionally, as we aim to update this page as more ideas flow in.


A Note About Suggested Grade Levels

Most of the teacher feedback we’ve received has been from those teaching grades 3, 4 and 5 with some 6th grade instructors also weighing in. This is primarily because the app is geared to independent readers (for reasons we’ll explain shortly). However, some teachers of younger students have found success reading the app in small groups to emerging readers and then letting them play briefly with the app’s interactive pages independently or in groups, so the students can experience the scientific concepts more directly. There are also numerous reviews from teachers on the Bobo Explores Light discussion page on If you’d like to dig deeper or cast about for a wider range of ideas, we’d encourage you to visit those reviews.


Independent Reading Level: Grade 3 and up

Teachers who use the app in the classroom generally report that independent readers can be entrusted with the app starting in Grade 3. (Lexile does not permit us to use their scoring system in our marketing materials, but publicly-available teacher reviews estimated our Lexile score to be in the range of 700, which strikes us as generally accurate, with a guided reading level of between J and Q.) We have so far resisted including a “read to me” feature in the app because we believe that younger users who may not be able to read the app themselves will benefit greatly from adult interaction, to help them understand some of the concepts covered. Happily, adults also love our app, as it covers many common questions posed by children, and which adults often struggle to answer (e.g. “Why is the sky blue?” or “How does lightning happen?” or “How do rainbows work?”).


Suggested Classroom Activities


We suggest trying the following activities after students have reviewed the entire app. (Chapter-specific activities to follow.) Note: some teachers introduce the app on an overhead projector or, if the A/V technology allows, they connect directly to a flatscreen or smartboard.

A light-related scavenger hunt:

At home or in the classroom, have students read the app in groups. Then, as a team, write down one real-life connection (per student) between the app and their surroundings. Example: if there is a fish tank in the classroom, they can point to it as an example of refraction. Or if the teacher has a laser pointer, they can mark that down. Or they might cite a light bulb as an example of one of Thomas Edison’s innovations. When presenting their findings, students can explain in their own words how that particular light-related element works. If they would like to illustrate that example, even better.

Timeline of Light:

For smaller groups or the entire classroom. Through discussion, create a timeline showing when various types of light were created or discovered on Earth. Starting with the Sun, then lightning and/or bioluminescence, then fire, fireworks, glow-in-the-dark substances (like radium on clock dials), lightbulbs, lasers, etc.

Classroom coloring book:

Each page in Bobo Explores Light can be saved and emailed in a screenshot form. Have students email their favorite page to the teacher’s email address, then print out the page in black and white format for students to color, copy or trace as they wish. Compile the results in a class-wide book.

Chapter-specific presentation stations for the classroom:

Challenge students to help create a demonstration station for each of the app’s 15 chapters. (Demo suggestions are included in each chapter-specific guide below.)

Chapter-specific activities and assessments:

Chapter 1: The Sun.

Activity: Using a clear measuring cup, fill one-half of a cup with salt and ask students to imagine the cup is the Sun. Pass out paper cups and then pass around a small bowl filled with salt. Ask them to remove the amount of salt that they think would represent the size of the Earth and put it in their cup. When everyone has had the chance to estimate, compare answers. Then reveal the real answer: the Earth would be the size of one grain of salt. (source:

Round-up quiz:

A. How many times could you fit the Earth into the Sun? (Answer: Around a million.)
B. What kind of gas is the Sun made from? (Answer: Hydrogen.)
C. How long has the Sun been burning? (Answer: Around 4 billion years.)
D. How much longer will the Sun burn? (Answer: Around 4 billion years.)
E. What is the solstice? (Answer: When the sun, at its apex for the day, reaches the highest and lowest point of the year.)

Demo suggestion: Model of the solar system, with a piece of trivia (from the app or elsewhere) attached to each planet and the Sun.

Chapter 2: Lightning.

Activity: With the iPad’s sound fully muted, show the chapter’s video of a slow-motion lightning storm. Ask students how long they believe this lightning storm lasted, and discuss their reasons behind their answers. Then play the video again, with volume on.

Round-up quiz:

A. How hot can a spark of lightning get? (Answer: 50,000 degrees Fahrenheit – which is hotter than the Sun.)
B. True or False: it is possible to have lightning in a snowstorm? (Answer: True.)
C. Is a bolt of lightning thicker or skinner than your fist? (Answer: Skinnier.)
D. When a storm cloud is ready to produce lightning, what does it have too much of? (Answer: Electrons.)
E. If you see a flash of lightning and it takes five seconds to hear the thunder, how far away is the lightning bolt? (Answer: Roughly one mile.)

Demo suggestion: A physical model of a lightning bolt, in real size (e.g. the thickness of a student’s fist).

Chapter 3: Fire.

Activity: School activity with fire? We think not. But a classroom discussion about how humans survived without fire’s heat, light and its potential for cooking? That sounds wiser.

Round-up quiz:

A. How many years ago did humans learn how to make fire? (Answer: 9,000 years. We’ve been on Earth around 500,000 years.)
B. What is a “flashpoint?” (Answer: The temperature at which various substances catch fire. For wood, it’s around 570 degrees Fahrenheit.)
C. Name one good use for ash? (Answer: Fertilizer for crops.)
D. How did fire help sailors survive? (Answer: Lighthouses helped them avoid rocky shores.)
E. What is a light made from? (Answer: Photons, which are particles that travel in waves.)

Demo suggestion: fake fire (fan pointed upwards with red strips of paper taped to fan’s face), with a list of flashpoints of various substances.

Chapter 4: Thomas Edison.

Activity: In groups, have students scan Edison’s various inventions and make a case for the most important of them.

Round-up quiz:

A. How heavy is the world’s biggest lightbulb and where is it? (Answer: 8 tons, located in Edison, N.J.)
B. When was the first lightbulb invented? (Answer: Around 1800 – long before Edison was born. Edison invented the first bulb that could be mass produced.)
C. How long has the world’s longest-lasting bulb been working? (Answer: More than 100 years.)
D. What type of lightbulb did Edison make – the incandescent, the fluorescent or the L.E.D.? (Answer: The incandescent.)
E. How does a patent help inventors? (Answer: It helps keep other people from copying your invention.)

Demo suggestion: Set up a light bulb with a household battery and have students complete the connection to light the bulb. (OR: set up a “potato battery” to complete the circuit.)

Chapter 5: Lasers.

Activity: Since lasers can, if mishandled, cause permanent eye damage, this is another case where hands-on activities would seem unwise. However, students can be sent on a laser scavenger hunt to find the things in the classroom or in their homes that already have lasers in them. (For example: a DVD player, the fiber optics of an audio speaker cable, and, of course, a laser pointer.)

Round-up quiz:

A. True or false: A light wave that is blue will change to a different color if that light wave is stretched or twisted to a different shape? (Answer: True. A light wave’s color is a function of its size and shape.)
B. True or false: If you wear glasses, doctors can fix your eyes by using lasers in surgery. (Answer: True.)
C. Name one interesting fact about the world’s most powerful laser. (Possible answers: It is located in California; it is a collection of 192 lasers and it can heat a speck of fuel to 5 million degrees Fahrenheit.)
D. What does the word “laser” come from? (Answer: Light Amplification by Stimulated Emission of Radiation.)
E. In red lasers, where does the color come from? (Answer: Rubies.)

Demo suggestion: Have students create a model, using Bobo’s diagram, showing the different parts of a laser.

Chapter 6: Reflection.

Activity: Using Bobo’s mirrors, challenge children to make a stream of light that connects through each of the mirrors (perhaps multiple times). For more options: One of the best resources we’ve found for mirror-related learning activities for kids is here. (It comes courtesy of the renowned toy inventor and children’s science guru Arvind Gupta.)

Round-up quiz:

A. When were modern-day mirrors invented? (Answer: The 1500s.)
B. What toxic element was first used to make mirrors? (Answer: Mercury.)
C. What are most mirrors made of today? (Answer: Silver or aluminum.)
D. True or false: ancient armies used mirrors to set fire to enemy ships? (Answer: True.)
E. What are photons, and why do they bounce off some surfaces and disappear into others? (Answer: Photons are particles of light that travel in waves. They bounce off of the smoothest surfaces but disappear into coarse surfaces.)

Demo suggestion: Mirror ball, convex (fisheye) mirror or, if possible, funhouse mirror, with quick explanation of how mirrored surfaces reflect photons.

Chapter 7: Refraction.

Activity: A great hands-on, teacher-led demonstration of refraction is the “disappearing glass” trick, which takes a little bit of planning but has magical results. (The best explanation we’ve found for it is here.) For four great refraction-related activities that students can engage in directly, check this page.

Round-up quiz:

A. How is spear-fishing made more difficult by refraction? (Answer: Because the fish aren’t really where they appear to be.)
B. Do your eyes refract light? (Answer: Yes – sometimes so much that things can go out of focus and you need glasses to see clearly.)
C. Does refraction slow down or speed up light waves? (Answer: It slows them down.)
D. What is a “refractometer?” (Answer: A device that measures how much light is refracted by a stone. It’s used to identify fake diamonds.)
E. Can air refract light? (Answer: Yes. That’s what happens in a mirage.)

Demo suggestion: Create a rainbow with a mirror and a flashlight (great explanation/diagram here) or a prism.

Chapter 8: Telescopes.

Activity: Bring in a pair of binoculars, and have students discuss, write about or draw diagrams of them to show how the binoculars are similar in design to telescopes. Discuss and record the objects they can see in the distance, and have students discuss or speculate about what they could change within the binoculars (or in the atmosphere) that would help them see even further away.

Round-up quiz:

A. What is the Hubbell telescope? (Answer: It’s a telescope that is flying through space and transmitting images back to Earth. It can see more than 100 trillion miles away.)
B. Where are the best telescopes on Earth based? (Answer: Hawaii.)
C. True or false: if you can make a curved piece of glass you can make a telescope? (Answer: True. A curved piece of glass – a.k.a., a lens – is the most important element.)
D. How does a lens work? (Answer: By squeezing light waves together and pointing them to a single spot where you can see them clearly.)
E. Which of the following things are lenses: a filled fishbowl, a window screen, a dark raincloud, and a TV screen? (Answer: fishbowl.)

Demo suggestion: Have students create a cardboard demo or diagram of a telescope, using diagram from Bobo’s holo-projector.

Chapter 9: Color.

Activity: Using the red, green and blue lights on the chapter’s home page, assign groups of students to create a specific color – for instance, the color of one student’s shirt – and talk about the percentage of red, green and blue needed to create that color.

Round-up quiz:

A. What is a wavelength? (Answer: The distance between the highest point of a light wave and the lowest point. Your eyes measure the distance and tell your brain which color the light wave is.)
B. True or false: some women have eyes with more color receptors than men, and are therefore better at identifying colors? (Answer: True.)
C. True or false: when light passes through a thin raincloud, it can bend – or refract — three times, and therefore create a rainbow? (Answer: False. The light waves are refracted twice, and on the second time the waves separate by color.)
D. What three colors are responsible for making up all the colors we see? (Answer: Red, green and blue.)
E. When you look at the color purple, what percentage of that color is made up of the color green? (Answer: Zero. It is a combination of red and blue.)

Demo suggestion: Color wheel, with RGB (red, green and blue) percentages. Good visual here.

Chapter 10: The Human Eye.

Activity: After reviewing this chapter in the app, have the students work in pairs and observe how often they blink in a 30-second span. Then observe and record how the partners’ pupils react in low light and bright light and discuss what is happening inside the eyes when that happens. (The rods inside their eyes are working harder in low-light situations, while the cones inside their eyes are working harder in brighter conditions.)

Round-up quiz:

A. True or false: The human eye sees things upside down, and your brain turns the images right-side up. (Answer: True.)
B. Most people blink how often during the day: 500, 1,000, 10,000, 100,000 (Answer: 10,000.)
C. True or false: humans can see ultraviolet light. (Answer: False; birds, however, can see ultraviolet light.)
D. What is rhodopsin? (Answer: A chemical that’s inside the rods of your eyes, and which helps your eyes determine the shape of a light wave in darker conditions.)
E. What is opsin? (Answer: A chemical that’s inside the cones of your eyes, and which helps your eyes determine the shape of a light wave in brighter conditions.)

Demo suggestion: Model of the human eye and its various parts. Or: pictures that show the difference between how human see the world, versus how various animals and insects see the world.

Chapter 11: Glow in the Dark.

Activity: Use glow in the dark paints to make a poster about light, using one of the other chapters in the app. Option 2: Using the home page in the app, have teams of students assemble the glow-in-the-dark pieces in various ways and then present their creations to the broader group.

Round-up quiz:

A. True or false: glow-in-the-dark materials work by reflecting light waves that we normally cannot see? (Answer: False: such materials work by absorbing and storing light and then releasing it slowly over time.)
B. What popular activities are enhanced by glow-in-the-dark materials: skydiving, cooking, scuba diving or lion taming? (Answer: Scuba divers. Their watches are often enhanced with glow-in-the-dark dials.)
C. True or false: airplanes often use glow-in-the-dark paint on the floor? (Answer: True. It’s a way of directing passengers to the exits in case the lights go out.)
D. True or false: dollar bills and other paper currency often contain glow-in-the-dark materials? (Answer: True: they help banks and storekeepers identify counterfeit money.)
E. Which chemical is commonly found in glow-in-the-dark materials: strontium aluminate; hydrogen peroxide; sodium chloride; dihydrogen monoxide. (Answer: strontium aluminate.)

Demo suggestion: Set up a box with glow-in-the-dark objects, visible through a peep hole. (Don’t forget to regularly expose the objects to light!)

Chapter 12: Bioluminescence.

Activity: After reviewing the bioluminescence chapter in the app in small groups, have students identify the coolest example of bioluminescence in nature and discuss. Or: in small groups and using a flashlight to signify bioluminescence, have students act out a specific scene that would involve an animal using bioluminescence to survive of thrive, and have the other students guess which animal it is.

Round-up quiz:

A. Why is the Lightfish one of the most populous animal species on Earth? (Answer: it uses bioluminescence to thwart predators.)
B. What is phosphorescence? (Answer: tiny organisms like plankton or algae that make bodies of water glow in the dark.)
C. How do some jellyfish use bioluminescence to survive? (Answer: When being pursued by predators, they leave a trail of glow-in-the-dark behind them to confuse their enemies into chasing that instead.)
D. What was Ben Franklin’s big idea involving bioluminescence? (Answer: Fill a submarine with glow-in-the-dark mushrooms so the sailors could see when they’re under water.)
E. What are luciferins and luciferase? (Answer: Chemicals that exist inside some animals. When their bodies mix them together, they glow in the dark.)

Demo suggestion: Build a small lightning bug out of cardboard or construction paper, with a small, push-button flashlight in its bottom. Include one-sentence trivia about how bioluminescence works in lightning bugs.

Chapter 13: Photosynthesis.

Activity: Have students plant two types of vegetables – one in direct sunlight and the other in poor light. Water them identically and record their growth and vegetable production. Other good suggestions can be found here.

Round-up quiz:

A. What three things must be present in order for photosynthesis to happen? (Answer: Sunlight, air and water.)
B. Where is photosynthesis more prevalent: Hawaii or the Sahara Desert? (Answer: Hawaii.)
C. True or false: photosynthesis can happen when the temperature is 50-degrees below zero? (Answer: False; water will freeze inside a plant’s cells, thereby preventing photosynthesis.)
D. What color do plants typically do the worst job absorbing? (Answer: Green. Plants reflect green light waves instead, which is why they appear to us as green.)
E. What are chlorophylls? (Answer: Green molecules that live in a plant’s cells. They absorb light and use the light’s energy to pull carbon dioxide from the air and the plant, to produce sugar and oxygen for growth.)

Demo suggestion: Grow plants and vegetables.

Chapter 14: Sunrise and Sunset.

Activity: After reviewing the chapter, have students observe the color of the sky and, in small groups, come up with explanations as to why the sky is blue. Gather and share answers. Next, discuss why the sky would look different around sunset. Option 2: ask students to write down the exact time of day when they believe the temperature would be lowest and share answers. (It is typically coldest just before dawn.)

Round-up quiz:

A. At what time of day is the temperature at its lowest? (Answer: The moments before sunrise, since, at that point, the Sun’s heat has been absent for the longest time.)
B. True or false: our atmosphere refracts light waves as they pass through? (Answer: True. It’s one reason the sky is blue.)
C. Why does the sky’s color look different at sunset and sunrise than it does in the middle of the day? (Answer: When the Sun is closer to the horizon, the light is refracted by air that has a different composition — more surface pollutants, for instance – than when it is at its apex.)

Demo suggestion: As a group or in small groups, have students paint a sunset mural with one-sentence of trivia about how the colors we see are affected by the atmosphere.

Chapter 15: Auroras.

Activity: Mute the iPad’s sound, and then, on an overhead projector or a smartboard, show students one of the two aurora videos and ask them to speculate about what is happening in the sky and why. After discussing their answers, discuss the scientific dynamics behind auroras.

Round-up quiz:

A. True or false: Auroras are caused by winds from solar storms. (Answer: True.)
B. Solar storms carry which of the following: protons, neutrons or electrons? (Answer: Electrons.)
C. Why are auroras more common toward the north and south poles? (Answer: Because the Earth’s magnetic force is greatest at these points, so the electrons carried by the solar winds are more forcefully drawn to these points.)
D. True or false: auroras and solar storms happen every year with the same intensity. (Answer: False; They happen every year, but the intensity builds and weakens, typically in ten-year cycles.)

Demo suggestion: As a group or in small groups, have students paint an aurora mural, with an explanation of how the colors we see depend on the height of the aurora in the sky.