# Heat, Light, and Sound

Subject:
Science
State Standards:
Utah State Science Core Curriculum Topic: ENERGY AFFECTS MATTER
Standard 6.2.3 Plan and carry out an investigation to determine the relationship between temperature, the amount of heat transferred, and the change of average particle motion in matter.

In these lessons, students investigate how energy moves through desert ecosystems in the form of heat, light, and sound. Students learn about insulators for heat and how sunscreen works to protect skin from UV light. They use sound to search for birds, and lenses to complete a scavenger hunt. The lesson concludes with a discussion about how too much heat, light, or sound can be harmful.

Essential Question: How do heat, light, and sound energy move through the natural environment?

Utah State Science Core Curriculum Topic: ENERGY AFFECTS MATTER
Matter and energy are fundamental components of the universe. Matter is anything that has mass and takes up space. Transfer of energy creates change in matter. Changes between general states of matter can occur through the transfer of energy. Insulators resist the transfer of heat energy, while conductors easily transfer heat energy. These differences in energy flow can be used to design products to meet the needs of society.

• Standard 6.2.3 Plan and carry out an investigation to determine the relationship between temperature, the amount of heat transferred, and the change of average particle motion in various types or amounts of matter. Emphasize recording and evaluating data, and communicating the results of the investigation. (PS3.A)

### Background

Energy is transported around the universe in the form of waves. Sound waves, light waves, ocean waves, heat waves, and radio waves are some examples. The shape of the wave determines its characteristics. Amplitude is the height of the wave. Crest is the top of the wave. Trough is the bottom of the wave. Frequency is the number of times the wave crests in a specific period. Wavelength is the distance between two crests. The speed of the wave is determined by multiplying the frequency times its wavelength.

Sound travels in waves. Sound is created by the vibrations or the back-and-forth movement of objects. When an object vibrates, it sends sound waves off in all directions. However, sound waves can only travel through mediums such as air, water, and objects. Sound cannot travel in a vacuum. Sound waves travel at different speeds through different mediums. The denser the material, the faster the wave travels. Pitch is the highness or lowness of a sound as we hear it. High-pitched sounds have a high frequency wave, and low-pitched sounds have a low frequency wave. Humans and animals communicate or express their thoughts by vibrating their vocal cords. Thicker cords vibrate more slowly and have a lower pitch. This causes the thicker strings on stringed instruments to produce deeper pitched tones. The intensity or the amplitude of the sound wave determines loudness.

The sun emits electromagnetic radiation in the form of waves. This radiation travels out from the sun in straight lines in all directions. A small portion of this radiation reaches the earth. We see small portions of this radiation as visible light. Upon encountering an object, light waves can be reflected, refracted, or absorbed. Light is bent when reflected. The angle at which the light is reflected depends on the shape of the surface it encounters and the angle at which the light strikes the surface. Many objects that appear to produce light are only reflecting the light of another object. Light traveling through a transparent object also bends or refracts the waves. The shape of the object determines how the light is bent. Prisms, and sometimes water drops, bend light so the different wavelengths are separated. Lenses bend light so objects appear larger or smaller depending on the shape of the lens. Humans have created many types of lenses to help us explore and understand the world. (Atwater et al, 1993)

UV light falls into the spectrum next to violet just out of our visual range. Since UV radiation has higher energy, it has a greater effect on living organisms than other wavelengths of light. Living things have adapted to a certain amount of UV, but excessive UV radiation causes sunburn, eye damage, immune system suppression, and greater risk of skin cancer in humans. Because of depletion of the stratospheric ozone layer, scientists have been monitoring UV radiation since the 1990s. People can avoid UV by staying inside during the midday hours (10am-4pm) since UV exposure is greatest when the sun is the most direct. They can wear clothing that absorbs UV radiation before it reaches the skin, such as wide-brimmed hats, long sleeves, pants, and sunglasses. They can also put on sunscreen to insulate their skin from some of the UV radiation.

Heat is the transfer of thermal energy between substances. Thermal energy is the energy which causes particles of matter to move. Temperature is the average measure of that energy. Thermal energy always moves from matter with greater thermal energy to matter with less thermal energy, so it moves from warmer to cooler substances.

Conduction is the transfer of thermal energy (heat) between particles of matter that are touching. This happens when two materials are in direct contact. Thermal conduction occurs when particles of warmer matter bump into particles of cooler matter and transfer some of their thermal energy to the cooler particles. This causes the molecules to move faster and bump into their neighbors, allowing more heat to move. Conduction happens faster and more efficiently in solids because the molecules in solids are tightly packed together compared to molecules in liquids and gases.

Radiation is the transfer of heat through open space in the form of waves. All warm objects emit heat waves (radiate).

Convection is the movement of heated molecules of a gas or a liquid from a heat source to another area, due to density differences within the gas or liquid. When gases are heated, they expand and become less dense, causing them to rise. Convection often happens when a hot fluid or gas moves upward, but it can also happen when a fan creates the movement. In contrast to conduction in which heat is transferred from molecule to molecule, heat is transferred by bulk flow of molecules in convection. (From Teach Engineering https://www.teachengineering.org/lessons/view/duk_heattransfer_smary_less#vocab)

Materials that reduce the movement of thermal energy are called thermal insulators. Thermal insulators keep hot things hot and cold things cold. Thick, fluffy materials, especially ones full of air, prevent heat loss by convection because they slow the movement of air. Insulators can also prevent heat movement by conduction, such as a pot gripper used to hold a hot pan.

### Procedure

Whose Got the Heat?

Essential Questions: What patterns can we investigate about which objects will retain or lose heat?

Materials: surface thermometers “temperature guns” (one per student); water thermometers (one per student); clipboards (2-3); pencils; New Heat Data Sheets; white board; dry erase marker; cup.

Procedure:
1) Ask students if the rocks they are sitting on feel hot or cold. Why are the rocks cold on such a hot day? Tell students that heat from the sun travels through space in waves. Objects absorb heat, then slowly transfer that heat through either conduction, convection, or radiation. Review their discussion about heat transfer at the pre-trip. Ask students if the temperature of the rocks has changed since they have been sitting on them. (2-3 min)

2) Ask students what they think is the hottest (and also the coldest) object in Lower Courthouse Wash. Demonstrate how to use the temperature gauges and distribute them. Encourage everyone to take the temperature of the rock along the bank of the stream and discuss variation in the measurements. Explore the temperature of various objects while walking back and forth to the solar oven as a group. At the solar oven, explain that the temperature guns do not work through glass and are not always accurate on shiny metal. Instead, look at the oven thermometer, and compare the temperature to other temps students have taken. Discuss how the greenhouse effect is trapping heat inside the oven. Finally, walk back to the ledge while examining the temperature of various surfaces (like metal, various rocks, plants, flowers, etc.) and generating questions about things to investigate. Record their observations. (10 min)

3) Tell students they will conduct an investigation to discover what objects radiate the most and the least heat. Tell them the first step in a scientific investigation is asking questions, which requires lots of creativity. Using the question formulation approach (or similar approach to generating a good list of questions), brainstorm a list of questions about heat. Write these on a whiteboard for the group. Then discuss our limitations, such as limited time, our location, and the tools available. Narrow down the list to questions students can investigate given the constraints. (5 min)

4) Divide students into pairs. Give each pair a clipboard, pencil, and New Heat Data Sheets. Have students write their chosen question and a list of objects they will measure. Check in with each pair about their question and procedures, briefly discuss proper replication of observations, and discuss boundaries. (10 min)

5) Gather the students and invite them to share their questions and results with the group. Discuss how their findings make Courthouse Wash a special place for plants and animals. (5 min)

6) Ask students what they like to do on a hot day. Review what they learned on the pre-trip about heat always moving to cooler objects. Pick a hot object and take its temperature, and then pour water on it. Take the temperature again and compare the results. Explain that the cold water rapidly absorbs heat energy, causing the temperature to fall, and then moves off, taking the heat energy with it. Ask students why the riparian corridor they are in is cooler than other areas in the summer. To further illustrate this point, take the skin temperature of one of students (on an arm or leg). Allow that student to hold their body part in the water for a moment and take the temperature again. Discuss the results. When you swim, you are giving your heat to the water through conduction, cooling you off.

The Sounds of Spring

Essential Questions: How can sound waves help us identify birds in courthouse wash?

Materials: International Migratory Bird Day poster (National Audubon Society and the U.S. Fish and Wildlife Service Division of Wildlife Refuges 1998); bird information and photo cards; binoculars in a separate bag; bird field guides; birdsong identiflyer with accompanying sound cards; birdsong (soundwave) picture: bird abundance data sheet.

Procedure:
1) Tell students they will act as ornithologists (scientists who study birds) at this station. Ask students what evidence we might discover that birds or other living things are present in Courthouse Wash. Ask students how birders might know a bird is nearby. Explain sometimes we cannot see birds, but we can hear them. Encourage them to use sound to locate birds. Preface the bird walk with the need for no talking and quiet walking. Pass out binoculars and show students how to use them. Tell students they are to keep track of how many different birdcalls they hear or birds they see. Keep track of how many birds students observe, sorting the data into songbirds, water birds, and raptors. Encourage students to share their discoveries by pointing to birds, frogs, nests, or other things they hear or see. Stop at the beaver dam and discuss how the beavers affected the bird habitat. Show students beaver pictures. Afterwards, collect binoculars, compare the groups data to data from other groups, and discuss patterns students notice. (10 min)

2) Mention that some birds students observe are only visiting Courthouse Wash. Discuss riparian areas as a resting area for migratory birds using the International Migratory Bird Day poster as a prop. Ask students to name some reasons birds migrate. Discuss the value of the Colorado River and its tributaries as a resting area on the Rocky Mountain Flyway. Spend a few minutes letting students look for birds they observed in bird books. Discuss which type of birds students most observed, and allow students to speculate why these were more common.

3) Ask students to name some reasons a bird might sing: call for mate, alert others to danger, tell others the location of food, for pleasure, check in with the flock, etc. Tell students that in all animals the pitch of the song or voice is determined by the size of the animal’s vocal chords. For example, boys’ voices change when their vocal cords get thicker. Explain birds have a syrinx instead of a larynx and its size determines the pitch of the bird’s song. (5 min)

4) Hand out a bird card to each student and ask them to find an interesting fact about the bird to share. Go around the circle and ask each student to share their bird’s name, picture, and an interesting fact about them. Play the call on the identiflyer, and ask students to predict which ones will be highest or lowest in pitch. (10 min)

5) Review how sound travels in waves. Birders try to figure out which direction the sound wave is coming from to help find the bird. Tell students many things can absorb sound waves before they reach the ears of another bird, human, or animal. Discuss what in the riparian area might absorb the sounds a bird makes. (5 min)

UV or Not UV?

Essential Questions: Can insulators protect our skin from damaging light waves? Which is the most effective?

Materials: UV sensitive beads in plastic bug boxes inside a covered box(10); beads inside tape cases for easier viewing(4); new sunscreen of various SPF numbers (100,50,30,&15 or less if available); old sunscreen; science investigation sheets; UV flip book; permanent marker; stopwatch; clipboards; pencils; water; rags; UV index comparison chart.

2) Ask students if they ever wondered which sunscreen they should purchase. Tell students they are going to conduct an experiment to find out how well different sunscreens work using UV beads, plastic cases, and sunscreens of different SPFs. Divide students into pairs, giving each pair an experiment form. Tell students they can test two sunscreens. Suggest questions students could investigate using the sunscreens available. They should only test one variable. Test how long a box without sunscreen takes to change colors as a control and then demonstrate how to cover the boxes of beads with sunscreen. Once students cover their first box, expose boxes to the light and record how long it takes for the beads to change color. Discuss preliminary observations comparing sunscreens various groups tested. Test the second sunscreen. Have students record data and write conclusions about which sunscreen insulated the beads from UV light the longest. (10-15 min)

3) Use the UV index chart to discuss what SPF means. Sun Protection Factor numbers help determine how long skin will be protected from burning. For example, an SPF of 30 may give you 30 times longer in the sun without skin damage than without sunscreen, depending on how much sunscreen is applied. Remind students our bodies metabolize sunscreen every 3-4 hours and most people don’t use enough sunscreen. Understanding how sunscreen works will help them know which one to purchase. As they get older, they will be responsible for taking care of their own skin and protecting themselves from UV light. We hope they choose to wear sunscreen. (5 min)

Uses of Lenses

Essential Questions: How can lenses help us to better understand the environment in Lower Courthouse Wash?

Materials: Bending Light flip book; prism, clipboards; paper; pencils; spoon; double convex lens; microscopes (4); hand lenses (6); binoculars (6); bug boxes (12).

Procedure:
1) Point to an object in the distance and ask students to describe it. Ask them if we could describe it in more detail without moving. Discuss why humans invented binoculars and telescopes and how these devices aid the exploration of our world and universe. Discuss why humans invented magnifying glasses and microscopes and how these devices aid in our understanding of our world. Describe scientific research being done by NPS scientists (for example, about raptors, bighorn sheep, and streams) and the tools these scientists use for this research. The key to all these tools is understanding a focal point.

2) Using the Bending Light poster and the spoon, explain all these devices are possible because light bends when it passes through glass, water, or plastic. The curvature of the lens determines how it bends, making an object appear bigger or smaller. Use a double convex lens to demonstrate how the light bends into a focal point. Ask how many students have ever used a focal point to burn a leaf? The lenses on our eyes also make a focal point. People with bad eyesight have lenses either too flat or too curved so the focal point does not fall on the back of their eyeball. Invite students to name other objects humans have created to bend light: glasses, camera lenses, etc. Crisp images from all these tools depend on the location of the focal point. (5 min)

3) Give students hand lenses, binoculars, and microscopes and allow them to explore how to use the tools. If needed, demonstrate proper use. Allow students to look in each side of the lens or see what happens if lenses are stacked. Practice focusing the microscopes using leaves and rocks. Discuss tradeoffs with each type of lens (3-5 min).

4) Introduce students to making observations about the life and geology of Lower Courthouse Wash. Demonstrate how to use the bug boxes to catch insects safely. Give boundaries about how far into the water they can go to collect aquatic insects and algae. If students are likely to find a bird’s nest, demonstrate how close you should go to the nest to observe the birds. Show students where they can collect rocks to examine. If necessary, only allow students to enter the water after they have studied two objects on land. (3-5 min)

5) Invite students to go on a scavenger hunt using the lenses. Students should find five amazing things using the lenses, one of which they will need to share. Hand out clipboards, paper, and pencils. Instruct students to write or draw and label their objects and include the tool they used. If necessary, have students compete to be the first to complete their scavenger hunt. (10-15 min)

6) After students turn in their pencils and lenses, ask each student to describe their favorite thing they observed. (2-3 min)

Can We Get Too Much?

Essential Question
: Where is the line between the right amount and too much? Does this line change depending on the situation? What are some alternative perspectives that might influence an answer?

Materials: Too Much? Questions

Procedure:
1) Review the field trip with students. Discuss the properties of heat, light, and sound. Tell students that throughout history, humans have produced their own heat, light, and sound. Often, the results are good. Ask students to point out some instances of artificial heat, light, or sound used in the classroom to help them learn. Explain that sometimes, however, too much of a good thing can cause harm. Describe an example. But, how much is too much can depend on the person or the situation.

2) Tell students they will form an opinion spectrum. Designate one end of the classroom as agreeing this scenario is OK all the time and the other end as never OK. The middle of the line represents when a situation might be influenced by circumstances. Set up some ground rules for your discussion. Ask a sample question (i.e. your mom brings home a tub of chocolate ice cream, would eating all the ice cream be okay or harmful) and tell students to decide how they feel about the situation and move to the appropriate part of the room. Invite students to discuss with students near to them why they choose their spot. Call on a few students to describe why they are standing where they are. Allow students to adjust where they are standing if their classmates’ arguments changed their thinking. Add another dimension to the situation, such as the ice cream is for their little brother’s birthday. Then tell students you will describe a situation where humans are producing heat, light, or sound and invite them to move around the room accordingly. Remind students that in real life, these questions are complicated. Absolute right or wrong answers seldom exist. When forming an opinion, they should consider themselves, other people, and the environment. After each situation, invite one or two representatives from each part of the room to explain their opinion to the class, and discuss situations that might impact their opinions.

3) As a class, discuss how some situations are good for humans but harmful to animals. Sometimes humans do not even realize our actions have unintended consequences. Discuss some instances where the value to humans might outweigh the harm caused to animals. Remind students that as they grow up, they will have to make decisions on their own. We encourage them to weigh the consequences for themselves, other people, and the natural world around them.

Too Much? Cards

1. Your neighbor leaves his car stereo on full blast. The sound is so great it shakes your windows.
2. The army uses sound to map the ocean floor.
3. You use sonar to find fish in the lake.
4. A city is lit up by streetlights at night.
5. There is always a radio or a television on in your home, but the volume is turned on low.
6. You use a chainsaw to cut firewood.
7. Spotlights light up an object throughout the night.
8. You hear fifteen different airplanes while you hike in a local national park.
9. Semi-trucks speed near your neighborhood going 55 miles an hour.
10. Two students are talking in class during a silent reading period.
11. A mother sings softly to her baby.
12.  A large parking lot is covered with blacktop; there are no trees.
13. Campers build a large campfire under a tree.
14. A home is heated throughout the winter using a woodstove.
15. You and your friends spend an entire night shinning your flashlight on sleeping creatures.
16. You help a friend produce a fireworks display on the Forth of July.

Atwater, M., Baptiste, P., Daniel, L., Hackett., et al. (1993). Wave energy: Teacher’s planning guide. New York: Macmillan/McGraw-Hill Science.

History of the microscope and optical lenses https://www.smithsonianmag.com/science-nature/what-we-owe-to-the-invention-microscope-180962725/https://en.wikipedia.org/wiki/History_of_optics

How hot is it (from Teach Engineering) https://www.teachengineering.org/lessons/view/cub_energy2_lesson06

Optics: Light, Color, and Their Uses Educator Guide | NASA
https://www.nasa.gov/stem-ed-resources/optics-guide.html

Sherwood, E., Williams, R., & Rockwell, R. (1990). More mudpies to magnets. Mt. Rainier, MD: Gryphon House.

Thermometer References- how temperature guns workhttps://blog.thermoworks.com/thermometer/how-to-use-an-infrared-thermometer/https://thermometer.co.uk/content/101-limitations-of-infrared-thermometers

Twiest, M. & Twiest, M. (2004) The scoop on sunscreen. Science and Children. V 41. N 9. Summer. pp 40-41.

Utah State Office of Education. (2002). Teacher resource book: Grade six. Salt Lake City: Author.

http://www.srrb.noaa.gov/UV/what.html.