Heat Energy You need a student booklet, answer key, boy scout situation, Bill Nye video set up, know food calorie vs. heat calorie Part 1

Bill Nye: Heat 1. Heat energy moves by… a. by conduction b. by convection c. by radiation d. all of the above 2. Molecules in cold things are… a. moving more slowly b. not moving c. moving more quickly d. without energy 3. Which has more energy? a. a burning match b. a large ice sculpture c. a small ice sculpture d. none of the above 4. The following can be use to fly: a. radiation b. convection c. conduction d. all of the above 5. Brownies bake faster in… a. glass pan b. metal pan c. mountain states d. at low atmospheric pressure

What is heat? What is heat? You tell me… Heat is thermal energy flowing from warmer to cooler objects. Thermal energy is the total energy of the particles of matter. Heat energy is produced by the internal motion of particles in matter. Matter is made of particles called molecules. The faster they move = the object is getting hotter. The slower they move = the object is getting colder.

Conduction Let’s look at page 1 in our books… Conduction is the heat transfer through a substance or from a substance to another by direct contact. Everything is made up of small particles. When the particles are moving faster, there is more energy and the temperature is higher. As fast-moving particles touch slow-moving particles, the energy is transferred. This causes slower particles to speed up and the faster particles to slow down. Turn to page 3 and let’s do the activity…

Activity Touch your hands to your cheeks. What do you feel? Rub your hands SLOWLY back and forth for 10 seconds. Rub your hands QUICKLY back and forth for 10 seconds. Why do you think the temperature changed?

So what is friction? Friction is the resistance between two objects rubbed together. More motion = More friction = More heat The energy of motion is called kinetic energy.

Temperature What do you already know about temperature? Temperature is the measure of the average kinetic energy of the molecules or particles of matter. The higher the temperature, the faster the molecules are moving. The lower the temperature, the slower the molecules are moving. Temperature can be changed. To increase the temperature, heat is added. To decrease the temperature, heat is removed.

Measuring Heat A calorie is a unit of energy We can measure the amount of heat in an object using the unit calorie. Calorie (food) vs. calorie (heat) https://www.youtube.com/watch?v=G0O87gWv-Xk 1 calorie raises the temperature of 1 gram of water 1 degree Celsius.

Boy Scout Scenario A group of by scouts arrived at camp and learned that their first task would be to build a fire. However, the scout masters wanted it to be a contest. The task was this: the first troop to build a fire and boil a pot of water would earn dinner cooked by the camp’s staff rather than having to cook their own meal for the evening. The scouts were given time to gather fire making supplies such as wood, and all the troops were given a pot the same size and made from the same material to make sure the contest was fair. Troop #13 was the very last group to get their fire started. They tried and tried, but it took them f-o-r-e-v-e-r. However, they were the very first group to get their pot of water to boil. Why?

Well… Troop #13 understood science! All the other troops filled their pots to the very top with cold water from the creek. Troop #13 just placed a small amount of water in their pot. Even though they started their fire last, their pot of water boiled first. Having less water required fewer calories, and they won a great dinner!

So which would boil faster? A small or a large pan of water? Why? A small pan would boil faster. Since it has less water, it requires fewer calories to boil.

What do we use to measure heat? Draw a picture of a thermometer How does a thermometer work? A thermometer contains a special liquid such as mercury or alcohol that has been dyed red. The liquid expands (gets bigger) when it gets hot. The liquid contracts (gets smaller) when it gets cold.

Thermometers continued The liquid has been trapped inside a glass tube, so it can only expand and contract up and down. Scientists know exactly how big or small the liquid will be at a given temperature, so they label or calibrate the thermometer. We can watch the level of the liquid inside the tube to know the temperature of a location or substance we are testing. The thermometer was invented by Gabriel Fahrenheit in 1724. Fahrenheit’s scale is 32ºF = freezing and 212ºF = boiling. A new scale was developed by Anders Celsius in 1742. Celsius’s scale is 0ºC = freezing and 100ºC = boiling.

Thermostat A thermostat is a device used to control the temperature of a room. The thermostat is set at the desired temperature. For example, 70ºF In the summer, if the room temperature rises above 70ºF, the air conditioner turns on to cool down the room. In the winter, if the room temperatures falls below 70ºF, the heater turns on to warm up the room.

Your Body’s Thermostat Your body also has a thermostat. A healthy body stays very close to 98.6ºF. If you become too hot, you sweat. This cools down your body. If you become too cold, you shiver. This heats up your body. This balancing act of keeping your body at the right temperature is known as homeostasis. It helps keep you healthy.