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Activity: Hot Bulbs Activity: Hot Bulbs

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Activity: Hot Bulbs Activity: Hot Bulbs

When you turn on a light bulb, what kinds of energy are being produced?

How can we compare the amount of each kind of energy produced?

Watts and calories are units used to measure energy: 860 cal per hr = 1 watt

Get

Started

Activity: Hot Bulbs Activity: Hot Bulbs

Yazmin noticed that after turning off a light, the bulb was hot to the touch. While some of the bulb's energy was converted to light energy, some was converted to heat. How much of the energy is 'lost' as heat?

Or, what is the efficiency of the bulb?

Read the introduction.

Introduction

Activity: Hot Bulbs

Challenge

What is the efficiency of a light bulb?

Challenge

Activity: Hot Bulbs

Procedure

• After setting up the procedure, keep track of your data using that data tables for part A.

Activity: Hot Bulbs

Procedure

Energy released (cal.) = temperature change (ºC) x mass of water (mL)

Energy absorbed (cal.) = time lit (minutes) x 27 calories per minute

Thermal energy output (%) = TEr/ TEax 100%

Light efficiency (%) = 100% - thermal energy output

For part B, you’ll need a second data table

Activity: Hot Bulbs

Follow Up

• Are light bulbs better at producing light or heat?

• Do you think inefficiency is a bigger concern in warm climates or cold ones?

An incandescent,

compact fluorescent,

and halogen bulb

Activity: Hot Bulbs

Follow Up

• Looking at the table below, which type of light bulb do you think is best?

• Most people buy incandescent bulbs. Why do you think this is?

Activity: Hot Bulbs Activity: Hot Bulbs

• Control

• Efficiency

• Incandescent

• Fluorescent

• Watt

Key

Vocabulary

Activity: Hot Bulbs

Key

Vocabulary

• Efficiency is the ratio of useful energy that is released by a process to the total energy absorbed by the process.

• Energy is the ability to cause objects to change, move, or work.

• Circuit is a path along which electrical energy can transfer

Activity: Hot Bulbs Activity: Hot Bulbs

Texas Essential Knowledge & Skills (TEKS)

§112.18. Science, Grade 6, Beginning with School Year 2010-2011.

(a)(4)(C) ... Thermal energy can be transferred by conduction, convection, or radiation. It can also

be changed from one form to another. Students will investigate the relationship between force and

motion using a variety of means, including calculations and measurements.

(c)(9) Force, motion, and energy. The student knows that the Law of Conservation of Energy

states that energy can neither be created nor destroyed, it just changes form. The student is

expected to:

◦ A) investigate methods of thermal energy transfer, including conduction, convection, and

radiation;

◦ (B) verify through investigations that thermal energy moves in a predictable pattern from

warmer to cooler until all the substances attain the same temperature such as an ice cube

melting; and

◦ (C) demonstrate energy transformations such as energy in a flashlight battery changes from

chemical energy to electrical energy to light energy.

TEKS ADDRESSED

Activity: Hot Bulbs Activity: Hot Bulbs

MS-PS3-4. ◦ Plan an investigation to determine the relationships among the energy

transferred, the type of matter, the mass, and the change in the average

kinetic energy of the particles as measured by the temperature of the

sample.

NGSS ADDRESSED