Science Focus Lesson SC.5.P.9.1 Physical /Chemical Changes Polk County Public Schools

SC.5.P.9.1 Benchmark: Investigate and describe that many physical and chemical changes are affected by temperature. Essential Question: How are physical and chemical changes affected by temperature? Vocabulary: physical change chemical change temperature

A physical change is a change that does NOT result in a new substance. Here are some examples of physical changes: Tearing paper Chopping Wood Breaking glass Popping a Balloon Cutting a Carrot Mixing Candy Sharpening a Pencil If you tear, chop, cut, break, pop, mix or sharpen in the examples above, it is a physical change. These changes will not result in a new substance.

When water changes states, these changes are also physical changes. Ice, water, and water vapor are all different forms of the same thing, WATER! No new substance is made. wwW Water in LIQUID form Water in SOLID form Water in GAS form (water vapor)

Temperature is very important as water changes states. Temperature is the measure of heat or energy in an object. A thermometer can be used to measure the heat. Water + Heat When water is heated, it changes state becoming a gas. Remember this is a physical change! =

Temperature is very important as water changes states. Temperature is the measure of heat or energy in an object. A thermometer can be used to measure the heat. Water + Cold When water is cooled, it changes state becoming a solid. Remember this is a physical change! =

With your shoulder partner, discuss what you think needs to happen for water to change states. Partner A – Tell B three examples of physical changes and how you think water changes to a solid Partner B – Tell A three different examples of physical changes and how you think water changes to a gas

How many of you can come up with the correct answers to the changes in matter challenge? You may work in pairs, teams or individually. Decide with your teacher. Fill in the blanks below. Question 1: If a solid is heated enough, it will eventually turn into a liquid. This is called _________________. Question 2: If a liquid is cooled enough, it will turn into a solid. This is called ________________. Question 3: If a solid is heated enough and boils, it will change into a liquid and will eventually ________________. Question 4: If a gas is cooled enough, it will change into a liquid. This is called _____________________.

A chemical change is a change that results in one or more new substances. Another term for chemical change is chemical reaction. Here are some examples of chemical changes: These familiar changes in materials result in other materials with different characteristics. Burning match Rusty nails Baked bread FireworksSour milk Digesting food Making putty

ClueExampleDescription Color ChangeBread dough baking Changes from white to brown SmellDecaying plants and animals Gives off a terrible smell New Physical Property Iron rustingChanges from hard and silvery to brittle and reddish brown Substance given off Wood burningSmoke is released into the air Heat given offSulfur burningFire is hot Bubbles FormedBaking soda and vinegar Bubbles are formed when mixed

Chemical changes are also affected by temperature. Remember that temperature is the measure of heat or energy in an object. If a chemical change has more heat or energy(a higher temperature), it is more likely that the reaction will happen. More heat or energy will also allow for a faster reaction in most chemical changes. Heat will make the particles in matter move more quickly which helps make a better reaction and reaction time.

With your shoulder partner, complete the following summary: 5 – Name and discuss 5 physical changes of matter 4 – Name and discuss 4 chemical changes 3 – Discuss 3 ways temperature can affect matter

Guided Practice Work with your shoulder partner to answer each question 1. One morning, Ryan noticed there were tiny drops of water on the grass as he walked to school. That afternoon, he did not see any drops of water on the grass when he returned home. Which of the following best explains what happened to the drops of water? A. The heat from the air caused the water drops to boil. B. The air cooled the water and caused the drops to freeze. C. The Sun heated the water and caused the drops to evaporate. D. The energy from the Sun caused the water drops to condense.

The Sun heated the water and caused the drops to evaporate.

2. Miguel and Angie built a metal fence around their garden. After several weeks of rain, Miguel noticed that the fence was rusting. Rusting is an example of which of the following? A. a chemical change B. a physical change C. a mixture forming D. a new kind of solution Guided Practice

A Chemical Change

3. Steven’s mom put a pot of water on the stove to cook spaghetti for dinner. Once the water started boiling, she put the spaghetti in the water. What caused the water to boil? A. the temperature of the water decreased B. the temperature of the water increased C. the temperature of the water decreased then increased D. the temperature of the water increased then decreased Guided Practice

The temperature of the water increased.

With your shoulder partner, discuss the changes water undergoes as it is heated and cooled.

Check Your Understanding Record your answers. Check them at the end. 1. Bonnie experimented with yeast. She put yeast and sugar into a bowl. She noticed that when she added warm water to the mixture, it bubbled. What could Bonnie infer about why the yeast mixture bubbled? A. The yeast and water boiled. B. A new element was created. C. A solution was made. D. A chemical change occurred.

2. Martha was excited about doing an experiment that would hopefully cause a chemical change. If she wanted to increase the chances of the chemical change occurring, which of the following should she do? A. Put the experiment in the refrigerator to decrease the temperature B. Let the experiment sit for several hours without touching it C. Heat the experiment to increase the temperature D. Cover the experiment with aluminum foil Check Your Understanding

3. Joey and his family went camping. Joey’s father gathered wood. He placed it in a fire ring. He lit a match. Soon the wood was burning. What did burning the wood cause? A. It caused a formation of a mixture. B. It caused physical change and new substances formed. C. It caused a chemical change and new substances to form. D. It caused a formation of a solution. Check Your Understanding

4. Which of the following is NOT a chemical change? A. Salt dissolves in water B. Logs burn in a fireplace C. Vinegar and baking soda combine to make a gas. D. A cake is baked Check Your Understanding

Check Your Answers 1. D 2. C 3. C 4. A

Write a summary paragraph explaining how physical and chemical changes are affected by temperature.