حل درس Physical and chimerical change العلوم منهج انجليزي الصف الخامس

حل درس Physical and chimerical change العلوم منهج انجليزي الصف الخامس

INQUIRY ACTIVITY

Hands On

Conservation of Mass

Think about how matter changes. such as the browning bananas. Investigate if the mass of matter changes when it appears to change

Make a Prediction Is mass conserved when matter combines with other matter

Sample answer: I think that the total mass of the substances will stay the same after the matter is combined because we don’t see the matter go anywhere so it must be in the new material

Carry Out an Investigation

BE CAREFUL Wear safety goggles during the investigation

. Fill one cup less than halfway with water. Put an equal amount of liquid school glue into the second cup

. Measure the mass of both cups separately and together. Record the mass in the data table on the next page

. Pour the water into the glue and mix them with a spoon

. Your teacher will add a spoonful of borax solution (about 5 grams) to your cup. Stir well with a spoon and observe

. Place both the empty cup and the cup with the mixture on the pan balance together. Record your result in the last column Of the table

 

INQUIRY ACTIVITY

 Make a bar graph of the mass of the materials before and after the reaction based on the results of the investigation

Students can graph the mass of the materials before and after the reaction in the form of a histogram or bar graph Did the matter after the reaction in this activity result in a new substance? Plan and conduct an investigation about how you could find out, Sample answer: While mass was conserved during the reaction, I could investigate whether the reaction resulted in a new substance by testing the properties of the original materials and the properties of the new material

 

MAKE YOUR CLAIM

How can you identify physical and chemical changes? Make your claim. use your investigation

CLAIM

Chemical changes

while physical changes

Sample answer: produce matter in a different form; begin and end with the same matter Cite evidence from the activity

EVIDENCE

The investigation showed that Sample answer: When the mixtures were combined, it formed a soft solid. When the water and borax were mixed, it formed a solution Discuss your reasoning as a class. Tell about your discussion

REASONING

The evidence supports the claim because Sample answer: chemical changes result in new matter with different properties, while physical changes keep the same properties

 You will revisit your claim to add more evidence later in this lesson

EXPLORE Lesson 3 Physical and Chemical

 

Changes in Matter

Think about the ways the banana was changing. Matter can be changed in many ways. A physical change begins and ends with the same kind of matter

 GO ONLINE Watch the vide Identifying Chemical Changes to learn more about how to recognize a chemical change

chemical change—also called a chemical reaction—is a change that produces new matter with different properties from the original matter. The law of conservation of mass states that matter is neither created nor destroyed during a physical change or chemical reaction. For example. when you mix baking soda with vinegar, particles in the baking soda and vinegar link up in new ways. During the chemical change

bubbles form and a solid is left behind. The new substances formed have different properties than the starting materials The properties of a piece of paper do not change if it iS 

flat or folded into a different shape After baking soda and vinegar react. water and a type of salt remain, and carbon dioxide bubbles are released

Signs of Chemical Change

Chemical changes produce new substances. Often you can see. hear. or smell the formation of new substances as a chemical change occurs. Below are some possible signs of chemical change

Change in Color The change from shiny metal to rust and tarnish shows that certain metals have chemically changed

Change in Odor Have you ever toasted marshmallows over a campfire ? An uncooked marshmallow has little odor. While your marshmallow is toasting. it gives off a pleasant smell. This change in odor is evidence of a chemical change

 

Temperature Change Many reactions cause matter to become warm or cold. Sometimes they also give off light, like when you burn wood. However. temperature change can also be part of a physical change. like water freezing

Formation of a Gas Bubbles or fizzing can indicate the release of a gas. For example, dropping antacid tablets into water will release bubbles that are the result of chemical change. Bubbles in soda are not a result of a chemical change, however

Formation of a Solid Chemical reactions of some solutions can form a solid. One exam le is Scum soa scum soap part.cies O’ mtnet Describe the cause and effect of one of the examples of a chemical change that you read about

Sample answer: When you have a campfire, the fire causes a temperature change, which changes the wood. The effects are increased temperature, more light, and a change in odor

COLLECT EVIDENCE

Add evidence to your claim on page 39 about how you can identify physical and chemical changes

 

What is causing

THE PHENOMENON

the banana to change

Summarize It

use what you have learned to explain what you know about physical and chemical changes. use the space below to write a summary or draw a diagram Of what can happen when materials are mixed

Sample answer: If a chemical change occurs when materials are mixed, you might notice a change in color, odor, or temperature

New matter will be produced. If a physical change occurs, no new matter will be produced

Revisit the Page Keeley Science Probe on PAGE KEELEY page 33. Has your thinking changed? If so SCIENCE explain how it has changed

 

Becoming a chemist is a noble career goal! Chemists can work in a variety of fields. You can start to take courses in high school to get an introduction to chemistry and higher- level math. This can help you figure out if you want to pursue a career as a chemist

If you want to become a chemist, you will take college courses in science and math You will also have the opportunity to get hands-on experience working with chemists in the field or helping with research in the lab. This will help you learn how to work with a team to solve problems as a chemist

It’s Your Turn

Some chemists specialize in food science How could a chemist help design the perfect pancake

ELABORATE Module: Matter