Does the Car Sun Shield Really Work? | DFRobot Science Lab Season 2 EP04
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AshG 2021-02-05 11:48:36

DFRobot Science Lab Season 2 

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EP04: Does the Car Sun Shield Really Work?

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Introduction
 

Standards

NGSS

4-PS3-2 Make observations to provide evidence that energy can be transferred from one place to another via sound, light, heat, and current.

4-PS3-4 Design, test, and optimize a device that can convert energy form from one to another based on scientific conception.

Science - Grade 3-5

Overview

In summer, our cars always get hot easily. How can we solve this problem? In this lesson, starting with this common phenomenon, we are going to test whether a sun shield is effective in shading and insulating the heat from the sun, and review the knowledge about heat transformation. Then, we are going to study which of the three materials, aluminum foil, corrugated paper and black EVA sponge paper, is more suitable for making sun shields for cars, so that we can learn the energy transformation process and the knowledge of thermal radiation.

Materials

Play and Learn with Boson Science Design Kit: https://www.dfrobot.com/product-2176.html

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Engage

Sunlight is everywhere, and we can’t live without it. But sometimes, it may also be annoying. For example, in open parking in summer, after continuous exposure to the sun, the car will be super-hot, like an oven. Every time you enter the car, you will feel like entering a sauna!

Many people have come up with many methods, such as turning on the AC to cool down in advance, or opening the door to have ventilation, while some people put a sun shield made of tin foil in front of the windshield to block out the sunshine and cool the car down.

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Do you think sun shields really work? Why are sun shields usually made of tin foil? If there is aluminum-foil paper, corrugated paper, black EVA sponge paper to be chosen, which one do you think is the best? Make a guess!

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Explore

We have already made a guess about the above two questions, now let's check it out!

The experiment will be divided into two parts. In the first part, the BOSON temperature sensor will be used to test whether the sun shield has a cooling effect through comparative experiments. In the second part, we will explore the cooling effect of aluminum aluminum-foil paper, corrugated paper and black EVA sponge paper respectively, and select materials more suitable for making sun shield.

Part1 Does Sun Shield Really Work?

In order to explore whether the sun shield really works, we can study it in real life. For example, find two vehicles, one with sun shield, while the other without. Carry out experiments under the same sunlight to compare the temperature changes inside the two vehicles.

With some simple materials, we can simulate this scenario. For example, take a lamp as a light resource, turn a plastic box upside down to simulate vehicle (plastic box can be used to simulate the enclosed interior of a vehicle), foil tape as a simple sun shield. We can carry out two groups of the controlled experiments, and draw conclusions through the comparison of temperature changes.

Record the value of temperature in the table below!

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It is suggested to guide the students to draw data into a line graph manually.

In the line graph, the horizontal line refers to time, while the vertical line refers to temperature. When drawing, mark the measured temperature values with points, and finally connect the points together in turn with a smooth curve. Distinguish the temperatures of different conditions with different colored lines, as shown in the figure below.

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Materials

Prepare the BOSON module and other materials below.

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Step

1. Build an experimental circuit to measure the environmental temperature

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2. Continue the following steps after finishing connecting the circuit. Set two groups of experiments, one with aluminum-foil paper and the other without. Illuminate them with strong light, and then record the temperature changes of the two groups.

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In the actual experiment, we can use two sets of equipment to carry out two groups of experiments at the same time, saving experimental time.

Conclusion

The referable experimental data are as follows (in the actual experiment, the room temperature is around 21℃):

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The referable line chart is as follows :

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It can be clearly informed from the line graph that when there is no aluminum-foil paper, the temperature rises all the time. After adding aluminum-foil paper, the temperature rises very slowly. Therefore, we can conclude that aluminum-foil paper does play a cooling effect, which means the sun shield really works.

Actually, a sun shield is just like a person with a sun umbrella. By blocking part of the light, the heat from the sun cannot be directly transferred to the covered object, so it plays a role in heat insulation. However, when the sun is very strong or the object is illuminated for a long time, do you think the sun shield is still useful?

Part 2 What Materials Should the Sun Shield Be Made of?

In the above experiment, we learned that sun shields do have a cooling effect, so what would be a better material to use to make them? Here we will explore the cooling effect of aluminum-foil paper, corrugated paper and black EVA sponge paper, and select the most suitable material.

On the basis of Part 1 experiment, only two groups of the controlled experiments with corrugated paper and black EVA sponge paper are needed. Record the data in the table below.

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Draw the data into a line chart for easy comparison.

Materials

On the basis of Part 1 experiment, add the following materials.

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Step

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In the actual experiment, we can use two sets of equipment to carry out two groups of experiments at the same time, saving experimental time

Conclusion

The referable experimental data are as follows (in the actual experiment, the room temperature is around 21℃):

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The referable line chart is as follows :

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Analyze the line chart, which material do you think is the best for making sun shields?

Think about why different materials are with different effects? Try to explain it from the perspective of light reflection.

Science Background

The sun brings warmth and light to the earth. It provides the earth with endless energy. That's why life on earth keeps growing. Do you know what energy is? Let's learn it together!

What Is Energy?

Energy is a basic physical concept, and it is also a very abstract concept. In the world, all things are in constant motion with various forms of motion. For every specific form of motion, there is corresponding form of energy, such as chemical energy of objects, heat energy of objects, radiation energy of sunlight, nuclear energy and so on.

Almost all the energy on the earth comes from the sun. The sun is like a big fireball with an extremely high temperature. Nuclear fusion is going on inside the sun, creating huge amounts of energy that radiates outward through the sun's rays and reaches the earth.

Energy is convertible, such as power plants that burn coal to convert chemical energy into electricity, or solar water-heaters that convert radiant energy from sunlight into heat energy from water.

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What Is Radiation?

Radiation is short for thermal radiation. It refers to the phenomenon that an object emits light and heat due to its temperature. Anything above absolute zero produces thermal radiation. The higher the temperature,the stronger the radiation.

Some light emitted by thermal radiation is visible to the naked eye, while the other invisible. Human body temperature is lower, radiates invisible infrared light, with very low energy. The sun is very hot, radiates a lot of light, and it's with high energy.

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Why use aluminum-foil paper to make sun shield of a car?

When light hits on an object, three things happen: part of the light can be absorbed by the object, part of the light can be reflected by the object, and part of the light can continue to spread through the object.

The light absorbed by the object is converted into heat energy, which heats up the object.

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Aluminum-foil paper, corrugated paper, and black EVA sponge paper reflect light differently. Aluminum-foil paper, which reflects light very well, with less light absorption and slow heating, is suitable for sun shield.

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Three ways of transferring heat

Heat radiation is one of the three ways in which heat is transferred, as well as by thermal conduction (conduction for short) and thermal convection (convention for short). As long as there is a temperature difference within or between objects, heat energy is bound to transfer from high temperature to low temperature in one or several of three ways. Here is an example.

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Thermal conduction refers to the transfer of heat from a hotter object to a cooler one, such as touching the handle of a pot.

Thermal convection refers to the transfer of heat by the flow of the liquid or gas, such as the circulation of water in boil.

Thermal radiation refers to the electromagnetic waves radiated by objects because of their temperature. For example, when you are near a fire, you feel warm.

Both thermal convection and conduction require contact. Since there is a vacuum between the earth and the sun, the sun transmits heat to the earth through thermal radiation.

Conclusion

In this project, we started our exploration from a common phenomenon in life:Do car sun shields really work? We used the BOSON temperature sensor for scientific experiments, and drew the conclusion. We also further explored the cooling effect of three kinds of material: aluminum-foil paper, corrugated paper, and black EVA sponge paper, to help us choose the most suitable one for making car sun shields. Besides, we studied relevant knowledge of the thermal radiation as well.

The project is going to an end, please remove cables, and put all the BOSON modules back into the original position of the kit.

Extent

1. Do you think the sun shield should be put inside or outside the car?

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2. Why can we warm ourselves with a heater in winter? Can you tell the scientific principles behind it?

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