TRANSPORTATION

# Bicycles

Science

## What You'll Need

• A set of gears – available at hobby, education, and discount retailers
• A small bicycle – coaster brake style
• Manual pencil sharpener – one you can take apart to show the gears
• Clock – one you can take apart to show the gears
• Rotary egg beaters – 1 for every 3 children

## What To Do

1. Display the set of gears. Ask children to describe the gears.
2. Demonstrate how to connect two gears on a table and how to move them. Show how to add more gears. Challenge the children to get all of the gears moving at once.
3. Show a picture of one of the gears that is connected to the other gears on the table. Ask the children how they can get one gear to move by touching the other gears. Give children the opportunity to use the other gears to try out their explanations.
4. Ask the children for some things that they think might have gears. Show the children the clock with the cover removed, the egg beater, and the pencil sharpener, and explore gears with them (see Guiding Student Inquiry).
5. Display the bicycle. Ask if it has any gears, where the gear is, and what has to happen to make the gear move. Challenge the children to tell you how to do that.
6. Once the children have had enough time to figure out that moving the pedals on the bicycle will make the gear move, ask them what other part of the bicycle is moving with the gear.
7. Explain that moving the pedals causes the gear to move the chain on the bicycle. When you pedal the bicycle, the pedals cause the gear to move the chain, which then moves the gear on the rear wheel, making the wheel move.
8. This bicycle is a form of transportation—like a car or a truck. The difference is that a bicycle does not need a motor to give it power; the rider pedaling is the power.

### Guiding Student Inquiry

• Explain how the gears move.
• Can you talk about what makes the gears move?
• Can the gears move by themselves? If not, why not?
• Let’s talk about how the bicycle moves.
• How is a bicycle the same as a car or truck? How is it different?

### Explore, Extend & Integrate

• Use the rotary egg beater to make pudding for a snack. Let the children help. Encourage them to examine how the gear in the rotary beater reacts when they turn the handle.
• If you have a water table, keep the rotary beaters by the water table for the children to use to experiment with the water.

### Check for Children’s Understanding

• Were the children able to explain how the gears moved the bicycle?
• Were the children able to explain that a bicycle is a form of transportation?

## Resources

### Did You Know?

Gears are simple machines; that means that a gear is a nonmotorized device that changes the direction or magnitude of a force. A gear is a wheel with teeth. For gears to work, at least two are needed. Two or more gears connected together make up a gear train. When the teeth of two gears are fit together, both gears move, but they move in opposite directions. Gears come in many sizes and help make moving objects easier. A large gear connected to a small gear will make the smaller gear turn more quickly, even though the larger gear is turning slowly. Gears are found in machines and in many things we use every day such as clocks, amusement park rides, and bicycles.

Early gears were made from wood and were powered by wind, water, or horses. These wooden gears could break easily and were soon replaced by metal gears. The first bicycle was wooden. It had no pedals and no gears. In the mid-1800s, the bicycle was changed by attaching the pedals to rotary gears. Bicycles of today contain several different sized gears that are connected by a chain. The gears help the bicycle move at different speeds when you pedal.

### Vocabulary: Child-Friendly Definitions

• gear – a part of a machine that causes another part to move because of teeth that connect the two moving parts
• crank – a device, sometimes with a handle, that moves things in a circle.
• rotary – turning or able to turn on an axis.
• bicycle – a light vehicle with two wheels, one behind the other. You make the wheels turn by pushing on pedals.
• simple machine – a device that functions in a manner basic to any machine such as a lever, pulley, wedge, screw, or inclined plane.
• transportation – the act of moving things or people from one place to another.

### Lesson Tips

• Search online to find a video of how gears work.
• It would be helpful to turn the bicycle over and prop it on its handlebars during your explanation. This will make it easier for the children to see the demonstration of the pedals turning the gear.
• Children are naturally very curious; be wary of small fingers getting too close to the gears of the rotary mixer and the chain of the bicycle.

### Books

• Gears Go, Wheels Roll by Mark Weakland
• Bicycle Book by Gail Gibbons
• Around the World: Bicycles by Kate Petty
• Bicycles (Transportation Library) by Lola M. Schaefer

### Home School Resources

Home educators: use these printable lesson PDFs to teach this lesson to your home schoolers. They're available in English and Spanish.

Home/School Connections

Las Conexiones a la Casa

While we believe that the books and resources recommended may be of value to you, keep in mind that these are suggestions only and you must do your own due diligence to determine whether the materials are appropriate and suitable for your use. PNC has no sponsorship or endorsement agreement with the authors or publishers of the materials listed.

## Content Provided By

Common Core State Standards Initiative – These lessons are aligned with the Common Core State Standards ("CCSS"). The CCSS provide a consistent, clear understanding of the concepts and skills children are expected to learn and guide teachers to provide their students with opportunities to gain these important skills and foundational knowledge [1]. Visit the CCSS